Cosmic Journeys : Supermassive Black Hole at the Center of the Galaxy
Published on Nov 5, 2013
Enjoy this updated, expanded version of our Cosmic Journeys episode. Feel the pull of the largest object in our galaxy, a supermassive black hole. Astronomers are discovering its properties by probing the objects that are buzzing around it at mind-boggling speeds.
From a distance, our galaxy would look like a flat spiral, some 100,000 light years across, with pockets of gas, clouds of dust, and about 400 billion stars rotating around the galaxys center. Thick dust and blinding starlight have long obscured our vision into the mysterious inner regions of the galactic center. And yet, the clues have been piling up, that something important, something strange is going on in there. Astronomers tracking stars in the center of the galaxy have found the best proof to date that black holes exist. Now, they are shooting for the first direct image of a black hole.
Titan’s Chemical Cocktail
Published on Oct 17, 2013
Dive into Titan’s thick atmosphere and find out what a strange place it is, adapted from NASA’s Scientific Visualization Studio. With its clouds, rain cycle, and giant lakes, Saturn’s large moon Titan is a surprisingly Earthlike place. But unlike on Earth, Titan’s surface is far too cold for liquid water – instead, Titan’s clouds, rain, and lakes consist of liquid hydrocarbons like methane and ethane (which exist as gases here on Earth). When these hydrocarbons evaporate and encounter ultraviolet radiation in Titan’s upper atmosphere, some of the molecules are broken apart and reassembled into longer hydrocarbons like ethylene and propane.
NASA’s Voyager 1 spacecraft first revealed the presence of several species of atmospheric hydrocarbons when it flew by Titan in 1980, but one molecule was curiously missing – propylene, the main ingredient in plastic number 5. Now, thanks to NASA’s Cassini spacecraft, scientists have detected propylene on Titan for the first time, solving a long-standing mystery about the solar system’s most Earthlike moon.
Voyager Leaves the Solar System
Published on Sep 20, 2013
Thirty-six years ago this month, on Sept. 5, 1977, the Voyager 1 spacecraft was launched from Cape Canaveral, Fla.
On September 12, 2013, NASA officially confirmed that Voyager 1 had reached the interstellar medium in August 2012. This makes Voyager 1 the first spacecraft to exit our solar system, a mark in history to be remembered forever.
Hear what today’s leading Astro-celebs have to say about Voyager’s incredible landmark accomplishment!
Published on Sep 9, 2013
A new type of exoplanet finder comes on line in the next year. Working with the giant telescopes of the Chilean outback, the Very Large Telescope on Mt Paranal, it will distinguish the polarized light of planet atmospheres from the light of their parent stars. This new planet detection system offers an ingenious new way to tease out the light of a planet with the overwhelming brightness of a star. Adapted from EsoCast, with Dr. J.
Hubble’s Time Tunnel
Published on Sep 6, 2013
One of the greatest scientific endeavors ever launched. Hubble sees back to the early days of the universe. Revel in this big picture look at what Hubble does, adapted from Hubblecast, with the incomparable Dr. J.
Published on Aug 16, 2013
From NASA’s Scientific Visualization Studio. Analysis of the meteor that flew in over Russia tells a surprising tale. Shortly after dawn on Feb. 15, 2013, a bolide measuring 18 meters across and weighing 11,000 metric tons, screamed into Earth’s atmosphere at 18.6 kilometers per second. Burning from the friction with Earth’s thin air, the space rock exploded 23.3 kilometers above Chelyabinsk, Russia.
The event led to the formation of a new dust belt in Earth’s stratosphere. Scientists used data from the NASA-NOAA Suomi NPP satellite along with the GEOS-5 computational atmospheric model to achieve the first space-based observation the long-term evolution of a bolide plume.
Titan: The Mystery of the Missing Waves
Published on Jul 25, 2013
Titan (or Saturn VI) is the largest moon of Saturn. It is the only natural satellite known to have a dense atmosphere and the only object, other than Earth, for which clear evidence of stable bodies of surface liquid has been found. However, these bodies of liquid are incredibly still, with no sign of wave activity. What is causing this incredible phenomenon?
Cosmic Journeys: Hyper Earth – the New World
Published on Jul 24, 2013
Incredible 4k supercomputer images of Planet Earth. Youtube plays them now at HD resolution. Youtube allows us to upload full UltraHD images now, and we hope the platform will begin streaming them in the next year.
Our world, Earth, is changing before our eyes. Go back millions of years. Forests reached into polar regions, sea levels rose, and temperatures soared with high levels of the greenhouse gas, carbon dioxide in the atmosphere. A long cooling period followed. But now CO2 is on the rise again. What will happen? How will we live in the New World that’s now emerging?
Scientists are intensively tracking the workings of planet Earth with satellites that chart its winds, ocean currents, temperatures, plant growth, and more. And with a new virtual Earth, shrunk down and converted into physical equations, satellite data, and computer codes they are able to show the workings of our planet in whole new ways..
This other Earth, a mirror of the one in which we live, is designed to follow the flow of heat through the complex, dynamic engine known as the climate… and to predict its future evolution. You can see the pattern of heat input in this sequence showing surface temperatures. As the seasons shift, heat builds and dissipates, most notably across tropical and subtropical regions. How does Earth dissipate this build up of heat? Look below. The oceans cover 71% of the planet’s surface, at an average depth of more than four kilometers.
They act like an immense battery that can store and release energy over long periods of time, while transporting heat from warm to cool regions. The oceans are set in motion by the unevenness of solar heating… due to the amount of sunlight striking the tropics versus the poles, along with the cycles of day and night and the seasons.
That causes warm, tropical winds to blow toward the poles, and cold polar air to push toward the equator. Wind currents, in turn, drive surface ocean currents. This computer simulation shows the Gulfstream winding its way north along the coast of North America. This great ocean river carries enough heat energy to power the industrial world a hundred times over.
It breaks down in massive whirlpools that spread warm tropical waters over northern seas. Below the surface, this current mixes with cold deep currents that swirl around undersea ledges and mountains. When heat builds within tropical oceans in late summer, it can be released in a fury.
Super-Earths: New Planets Found!
Published on Jun 26, 2013
Astronomers working at the European Southern Observatory (ESO) in Chile have discovered seven planets orbiting the star Gliese 667C.
Two exoplanets have been discovered in the star’s habitable zone, which has just the right range of distance where liquid water can exist on a planet’s surface.
A super-Earth is an extrasolar planet with a mass higher than Earth’s, but substantially below the mass of the Solar System’s smaller gas giants Uranus and Neptune, which are both more or less 15 Earth masses.
The term super-Earth refers only to the mass of the planet, and does not imply anything about the surface conditions or habitability.
Astronomers at the European Southern Observatory in Chile found out that 40 per cent of red dwarves are orbited by super-Earths. Red Dwarfs are by far the most common type of star in the Milky Way galaxy, so there might be tens of billions of such planets in our galaxy alone.
No Gentle Galaxy Collision
Published on Jun 23, 2013
From Hubblecast, a vivid new image of colliding galaxies known as Arp 142. When two galaxies stray too close to each other they begin to interact, causing spectacular changes in both objects. In some cases the two can merge — but in others, they are ripped apart.
Just below the center of this image is the blue, twisted form of galaxy NGC 2936, one of the two interacting galaxies that form Arp 142 in the constellation of Hydra. Nicknamed “the Penguin” or “the Porpoise” by amateur astronomers, NGC 2936 used to be a standard spiral galaxy before being torn apart by the gravity of its cosmic companion.
The remnants of its spiral structure can still be seen — the former galactic bulge now forms the “eye” of the penguin, around which it is still possible to see where the galaxy’s pinwheeling arms once were. These disrupted arms now shape the cosmic bird’s “body” as bright streaks of blue and red across the image. These streaks arch down towards NGC 2936’s nearby companion, the elliptical galaxy NGC 2937, visible here as a bright white oval. The pair show an uncanny resemblance to a penguin safeguarding its egg.
The effects of gravitational interaction between galaxies can be devastating. The Arp 142 pair are close enough together to interact violently, exchanging matter and causing havoc.
Hubble Realms of Light (in 4k UHD)
Published on May 28, 2013
Getting ready for the advent of 4k TV. Revel in some of the highest resolution images from the Hubble Space Telescope. Even now you can see the detail now in these inspiring images, but be sure to check back when you have lined up your 4k monitor or TV in the coming years.
The Mighty Ring
Published on May 23, 2013
The NASA/ESA Hubble Space Telescope and Hubblecast bring you a new and detailed look at the famous Ring Nebula. The Ring’s distinctive shape makes it a popular illustration for astronomy books. But new observations of the glowing gas shroud around an old, dying, Sun-like star reveal a new twist.
Hubble and several ground-based telescopes have combined to obtain the best view yet of the iconic nebula. The images show a more complex structure than astronomers once thought and have allowed them to construct the most precise 3-D model of the nebula.
The Ring Nebula is about 2,000 light-years from Earth and measures roughly 1 light-year across. Located in the constellation Lyra, the nebula is a popular target for amateur astronomers. Previous observations by several telescopes had detected the gaseous material in the ring’s central region. But the new view by Hubble’s sharp-eyed Wide Field Camera 3 shows the nebula’s structure in more detail. The ring appears to wrap around a blue, football-shaped structure. Each end of the structure protrudes out of opposite sides of the ring.
The nebula is tilted toward Earth so that astronomers see the ring face-on. In the Hubble image, the blue structure is the glow of helium. Radiation from the white dwarf star, the white dot in the center of the ring, is exciting the helium to glow. The white dwarf is the stellar remnant of a Sun-like star that has exhausted its hydrogen fuel and has shed its outer layers of gas to gravitationally collapse to a compact object.
The dark, irregular knots of dense gas embedded along the inner rim of the ring look like spokes in a bicycle wheel. These gaseous tentacles formed when expanding hot gas pushed into cool gas ejected previously by the doomed star. The knots are more resistant to erosion by the wave of ultraviolet light unleashed by the star. The Hubble images have allowed astronomers to match up the knots with the spikes of light around the bright, main ring, which are a shadow effect. Astronomers have found similar knots in other planetary nebulae.
All of this gas was expelled by the central star about 4,000 years ago. The original star was several times more massive than our Sun. After billions of years converting hydrogen to helium in its core, the star began to run out of fuel. It then ballooned in size, becoming a red giant. During this phase, the star shed its outer gaseous layers into space and began to collapse as fusion reactions began to die out. A gusher of ultraviolet light from the dying star energized the gas, making it glow.
The outer rings were formed when faster-moving gas slammed into slower-moving material. The nebula is expanding at more than 43,000 miles an hour, but the center is moving faster than the expansion of the main ring. The Ring Nebula will continue to expand for another 10,000 years, a short phase in the lifetime of the star. The nebula will become fainter and fainter until it merges with the interstellar medium.
Studying the Ring Nebula’s fate will provide insight into the Sun’s demise in another 6 billion years. The Sun is less massive than the Ring Nebula’s progenitor star, so it will not have such an opulent ending.
Hypnotic Solar Explosions in 4k
Published on May 8, 2013
To the naked eye, our sun is an unremarkable ball of heat and light. Under the eye of the Solar Dynamics Observatory, or S.D.O, the Sun’s activity is revealed under various spectrums of light. See incredibly detailed coronal mass ejections, bursts, and solar flares. Let the immense power of the sun immerse and mesmerize you in stunning Ultra High Definition.
Solar Rain of Fire, in 4k (UHD)
Published on May 2, 2013
This 4k UHD video captures what may be the most spectacular solar event ever witnessed. On July 19, 2012, an eruption occurred on the sun that produced a moderately powerful solar flare and coronal mass ejection. It produced a dazzling magnetic display known as coronal rain. Hot plasma in the corona cooled and condensed along strong magnetic fields that extended out from the solar surface. Charged plasma is forced to move along the lines, showing up brightly in the extreme ultraviolet wavelength of 304 Angstroms, and outlining the fields as it slowly rains back down onto the solar surface.
The video was uploaded at 3840×2160 UHD resolution. The Youtube player cuts that in half, but you can always download it at full res on your spiffy new 4k screen. Or wait till Apple releases its 4k iTV.
Music by Kevin Macleod (“Decisions”) and DigitalR3public (“Restart”).
The Curvature, Earth from Space in 4k (UHD)
Published on Apr 29, 2013
Watch this on the largest screen available. This 4k video features some of the most astonishingly beautiful images from the Gateway to Astronaut Photography based at NASA’s Johnson Space Center. How can anyone ever tire of gazing on the gentle curvature of mother Earth as seen from the International Space Station.
Solving Cosmic Cold Cases
Published on Apr 10, 2013
From ESO, spectacular star-filled nights frame the telescope array of the new ALMA project, where scientists are taking on the mysteries of the cold hidden reaches of the universe. ALMA is the world’s largest astronomical project. But it is not a conventional telescope. Instead of collecting and analyzing visible light it looks in a different and largely unmapped part of the spectrum. By opening a new window on the cosmos, ALMA explores one of the last frontiers of astronomy — the cold and distant Universe. All in search of answers to some of the deepest questions about our cosmic origins. How do stars and planets form? How did the first galaxies form?
Sixty-six state-of-the-art antennas observe the Universe at millimeter and submillimeter wavelengths — one thousand times longer than visible wavelengths. This light reaches us from some of the coldest and most distant objects in the Universe. Water vapor in the atmosphere blocks these faint whispers from the hidden Universe, so to collect them we have to go to an extremely high and dry site — like Chajnantor.
The 66 antennas on the high plateau are a critical part of ALMA. Their big dishes collect the faint millimeter waves from space. These antennas are truly the state-of-the-art. Their surfaces are accurate to much less than the thickness of a sheet of paper. They can move precisely enough to pick out a golf ball at a distance of 15 kilometers.
In a truly global endeavor, the antenna components were constructed in several locations around the world, sent to Chile to be assembled. Detectors in each antenna register the finest nuances of the faint signals collected by the dishes. These detectors are the most sensitive of their kind and are cooled using helium gas to just four degrees above absolute zero.
Millimeter and submillimeter wavelengths give astronomers a unique window on the Universe. But to see them with the sharpness astronomers need, a single-dish telescope would have to be kilometers across (and impossible to build)! Instead, ALMA uses 66 separate antennas which can be spread out over the plain with separations of up to 16 kilometers. The antennas are linked and their signals combined. The result: one giant telescope as wide as the whole array, observing with unprecedented sensitivity and resolution.
Cosmic Journeys : Voyager Journey to the Stars
Published on Apr 6, 2013
Cosmic Journeys examines the great promise of the Voyager mission and where it will lead us in our grand ambition to move out beyond our home planet. The two Voyager spacecraft are part of an ancient quest to push beyond our boundaries… to see what lies beyond the horizon. Now tens of billions of kilometers from Earth, two spacecraft are streaking out into the void. What will we learn about the Galaxy, the Universe, and ourselves from Voyager’s epic Journey to the stars?
December 19, 1972… the splashdown of the Apollo 17 crew capsule marked the end of the golden age of manned spaceflight. The Mercury…. Gemini… and Apollo programs had proven that we could send people into space… To orbit the Earth…. Fly out beyond our planet… Then land on the moon and walk among its ancient crater.
The collective will to send people beyond our planet faded in times of economic uncertainty, war, and shifting priorities. And yet, just five years after Apollo ended, scientists launched a new vision that was just as profound and even more far-reaching.
It didn’t all go smoothly. Early computer problems threatened to doom Voyager 2. Then its radio receiver failed, forcing engineers to use a back up. Now, after more than three and a half decades of successful operations, the twin spacecraft are sending back information on their flight into interstellar space. Along the way, they have revealed a solar system rich beyond our imagining.
The journey was made possible by a rare alignment of the planets, a configuration that occurs only once every 176 years. That enabled the craft to go from planet to planet, accelerating as they entered the gravitational field of one, then flying out to the next. The Voyagers carried a battery of scientific equipment to collect data on the unknown worlds in their path. That included a pair of vidicom cameras, and a data transfer rate slower than a dialup modem.
Published on Apr 3, 2013
Stunning imagery illustrates Hubble Space Telescope part in a global scientific effort to understand how stars explode, what effect they have on the universe, and what they can tell us about its origins and future. From Hubblecast.
Most stars in the Universe are small and insignificant, like our Sun They eventually fizzle and die without much drama. But a few light up the sky when they die, and in the process, they don’t just tell us about the lives of stars: they create the building blocks of life, and help us to unravel the whole history of the Universe. These are the stars that end their lives as supernovae, explosions that are among the most violent events in the Universe.
Curiosity’s First Major Discovery
Published on Mar 15, 2013
Here are the details of Curiosity’s discovery of ancient conditions in Yellowknife Bay in Mars’ Gale Crater, from NASA’s Jet Propulsion Lab. Ancient Mars could have supported living microbes. That’s what the Mars Curiosity turned up in its first major discovery. Scientists identified sulfur, nitrogen, hydrogen, oxygen, phosphorus and carbon — some of the key chemical ingredients for life — in the powder Curiosity drilled out of a sedimentary rock near an ancient stream bed in Gale Crater on the Red Planet last month.
The data indicate the Yellowknife Bay area the rover is exploring was the end of an ancient river system or an intermittently wet lake bed that could have provided chemical energy and other favorable conditions for microbes. The rock is made up of a fine-grained mudstone containing clay minerals, sulfate minerals and other chemicals. This ancient wet environment, unlike some others on Mars, was not harshly oxidizing, acidic or extremely salty.
The patch of bedrock where Curiosity drilled for its first sample lies in an ancient network of stream channels descending from the rim of Gale Crater. The bedrock also is fine-grained mudstone and shows evidence of multiple periods of wet conditions, including nodules and veins.
Curiosity’s drill collected the sample at a site just a few hundred yards away from where the rover earlier found an ancient streambed in September 2012. The clay minerals it found are a product of the reaction of relatively fresh water with igneous minerals, such as olivine, also present in the sediment. The reaction could have taken place within the sedimentary deposit, during transport of the sediment, or in the source region of the sediment. The presence of calcium sulfate along with the clay suggests the soil is neutral or mildly alkaline.
Scientists were surprised to find a mixture of oxidized, less-oxidized, and even non-oxidized chemicals, providing an energy gradient of the sort many microbes on Earth exploit to live. This partial oxidation was first hinted at when the drill cuttings were revealed to be gray rather than red.
NASA Telescope Discovers the Origin of Cosmic Rays
Published on Feb 21, 2013
From NASA’s Scientific Visualization Studio. A new study using observations from NASA’s Fermi Gamma-ray Space Telescope reveals the first clear-cut evidence that the expanding debris of exploded stars produces some of the fastest-moving matter in the universe. This discovery is a major step toward meeting one of Fermi’s primary mission goals.
Cosmic rays are subatomic particles that move through space at nearly the speed of light. About 90 percent of them are protons, with the remainder consisting of electrons and atomic nuclei. In their journey across the galaxy, the electrically charged particles become deflected by magnetic fields. This scrambles their paths and makes it impossible to trace their origins directly.
Through a variety of mechanisms, these speedy particles can lead to the emission of gamma rays, the most powerful form of light and a signal that travels to us directly from its sources. Two supernova remnants, known as IC 443 and W44, are expanding into cold, dense clouds of interstellar gas. This material emits gamma rays when struck by high-speed particles escaping the remnants.
Scientists have been unable to ascertain which particle is responsible for this emission because cosmic-ray protons and electrons give rise to gamma rays with similar energies. Now, after analyzing four years of data, Fermi scientists see a gamma-ray feature from both remnants that, like a fingerprint, proves the culprits are protons.
When cosmic-ray protons smash into normal protons, they produce a short-lived particle called a neutral pion. The pion quickly decays into a pair of gamma rays. This emission falls within a specific band of energies associated with the rest mass of the neutral pion, and it declines steeply toward lower energies. Detecting this low-end cutoff is clear proof that the gamma rays arise from decaying pions formed by protons accelerated within the supernova remnants.
Cosmic Journeys : Plasma Rockets & Solar Storms
Published on Feb 15, 2013
Join a small team of rocket designers as they open a window into the future of space travel. Stirring music from Digital Republic.
Modern science has linked polar light shows, called auroras, to vast waves of electrified gas hurled in our direction by the sun. Today, researchers from a whole new generation see this dynamic substance, plasma, as an energy source that may one day fuel humanity’s expansion into space. What can we learn, and how far can we go, by tapping into the strange and elusive fourth state of matter?
Since the dawn of rocketry, we’ve relied on the same basic technology to get us off the ground. Fill a cylinder with volatile chemicals, then ignite them in a controlled explosion. The force of the blast is what pushes the rocket up. Nowadays, chemical rockets are the only ones with enough thrust to overcome Earth’s gravity and carry a payload into orbit. But they are not very efficient.
The heavier the payload, the more fuel a rocket needs to lift it into space. But the more fuel a rocket carries, the more fuel it needs. For long-range missions, most spacecraft rely on their initial launch speed to essentially coast to their destination. Flight planners often design routes that give the craft a gravity assist by sending it around the moon or another planet. One small cadre of scientists believes it has a quicker and more efficient way to get around in space.
Dr. Ben Longmier and his team from the University of Michigan have traveled to Fairbanks, Alaska to play a small part in a much larger push to revolutionize space travel and exploration.
The team plans to use helium balloons to send components of a new type of rocket engine to an altitude of over 30 kilometers, above 99% of Earth’s atmosphere. The purpose is to test these components within the harsh environment of space. While astronauts train to live and work in zero gravity, or to move around in bulky space suits, these would-be space explorers are preparing to negotiate some of Earth’s harshest environments.
Once they launch their payload, they have to retrieve it wherever it comes down in Alaska’s vast snowy wilderness. The idea they are pursuing is nothing short of revolutionary. It’s a type of rocket that promises far greater gas mileage than other rockets, and enough power to reach distant targets. It runs on the same fuel that nature uses, literally, to power the universe: plasma.
Black Hole Galaxy Sculptor
Published on Feb 5, 2013
The NASA/ESA Hubble Space Telescope — with a little help from an amateur astronomer — has produced one of the best views yet of nearby galaxy Messier 106, a striking spiral galaxy with a number of secrets.
Located a little over 20 million light-years away, practically a neighbor by galactic standards, Messier 106 is one of the brightest and nearest spiral galaxies to our Milky Way. Although it may not look particularly unique, some of its features have baffled astronomers for years.
Messier 106 has a supermassive black hole at its centre. Although this is true for most galaxies, this black hole is particularly active and hungry, gobbling up nearby material at a startling rate.
This huge black hole’s bottomless appetite is behind much of the galaxy’s unusual behavior. Messier 106 appears to be emitting powerful radiation from its centre — something we do not see with our Milky Way or other similar spirals. This is caused by the very active black hole at the galaxy’s centre, which violently drags gas and dust inwards. This material heats up, emitting bright microwave and X-ray radiation as it does so.
However, this emission is not the most intriguing feature of this spiral galaxy. This image shows the galaxy’s other not-so-hidden secret — alongside its two regular star-packed spiral arms, it appears to have two more, made of hot, glowing gas. While these extra arms have been known about for decades, astronomers were unsure of how they formed — until recently.
The Quantum Guide – Search for the Higgs Particle
Published on Jan 31, 2013
Deep underground, the training of the Earth’s new generation of space colonists continues. Jarl Quarkson has mastered his study of some of the workings of space; of pulsars, gamma rays, and the Earth’s capabilities to capture data using FERMI. But while he is comfortable with that knowledge, his instructor, Cerin Higami, has approached him with a new assignment—one that will reshape Jarl’s view of the very fabric of the cosmos.
To understand where we want to go, Jarl must first understand where we came from, starting with the quest to understand the beginnings of the universe.
Cosmic Journeys: Venus – Death of a Planet
Published on Jan 16, 2013
Watch this updated full res 1080p version of our classic show. Why did Earth thrive and our sister planet, Venus, died? From the fires of a sun’s birth… twin planets emerged. Then their paths diverged. Nature draped one world in the greens and blues of life. While enveloping the other in acid clouds… high heat… and volcanic flows. Why did Venus take such a disastrous turn?
For as long as we have gazed upon the stars, they have offered few signs… that somewhere out there… are worlds as rich and diverse as our own. Recently, though, astronomers have found ways to see into the bright lights of nearby stars.
They’ve been discovering planets at a rapid clip… using observatories like NASA’s Kepler space telescope… A French observatory known as Corot … .And an array of ground-based instruments. The count is approaching 500… and rising. These alien worlds run the gamut… from great gas giants many times the size of our Jupiter… to rocky, charred remnants that burned when their parent star exploded.
Some have wild elliptical orbits… swinging far out into space… then diving into scorching stellar winds. Still others orbit so close to their parent stars that their surfaces are likely bathed in molten rock. Amid these hostile realms, a few bear tantalizing hints of water or ice… ingredients needed to nurture life as we know it. The race to find other Earths has raised anew the ancient question… whether, out in the folds of our galaxy, planets like our own are abundant… and life commonplace? Or whether Earth is a rare Garden of Eden in a barren universe?
With so little direct evidence of these other worlds to go on, we have only the stories of planets within our own solar system to gauge the chances of finding another Earth. Consider, for example, a world that has long had the look and feel of a life-bearing planet. Except for the moon, there’s no brighter light in our night skies than the planet Venus… known as both the morning and the evening star.
The ancient Romans named it for their goddess of beauty and love. In time, the master painters transformed this classical symbol into an erotic figure. It was a scientist, Galileo Galilei, who demystified planet Venus… charting its phases as it moved around the sun, drawing it into the ranks of the other planets.
With a similar size and weight, Venus became known as Earth’s sister planet. But how Earth-like is it? The Russian scientist Mikkhail Lomonosov caught a tantalizing hint in 1761. As Venus passed in front of the Sun, he witnessed a hair thin luminescence on its edge.
Venus, he found, has an atmosphere. Later observations revealed a thick layer of clouds. Astronomers imagined they were made of water vapor, like those on Earth. Did they obscure stormy, wet conditions below? And did anyone, or anything, live there?
NASA sent Mariner 2 to Venus in 1962… in the first-ever close planetary encounter. Its instruments showed that Venus is nothing at all like Earth. Rather, it’s extremely hot, with an atmosphere made up mostly of carbon dioxide.
The data showed that Venus rotates very slowly… only once every 243 Earth days… and it goes in the opposite direction. American and Soviet scientists found out just how strange Venus is when they sent a series of landers down to take direct readings.
Surface temperatures are almost 900 degrees Fahrenheit, hot enough to melt lead, with the air pressure 90 times higher than at sea level on Earth. The air is so thick that it’s not a gas, but a “supercritical fluid.” Liquid CO2. On our planet, the only naturally occurring source is in the high-temperature, high-pressure environments of undersea volcanoes. It comes in handy for extracting caffeine from coffee beans… or drycleaning our clothes.
You just wouldn’t want to have to breathe it. The Soviet Venera landers sent back pictures showing that Venus is a vast garden of rock, with no water in sight. In fact, if you were to smooth out the surface of Venus, all the water in the atmosphere would be just 3 centimeters deep. Compare that to Earth… where the oceans would form a layer 3 kilometers deep.
If you could land on Venus, you’d be treated to tranquil vistas and sunset skies, painted in orange hues. The winds are light, only a few miles per hour… but the air is so thick that a breeze would knock you over. Look up and you’d see fast-moving clouds… streaking around the planet at 300 kilometers per hour. These clouds form a dense high-altitude layer, from 45 to 66 kilometers above the surface.
The clouds are so dense and reflective that Venus absorbs much less solar energy than Earth, even though it’s 30% closer to the Sun.
The Quantum Guide – Pulsars
Published on Jan 15, 2013
Unknown to the general populace, young men and women from around the globe are being raised in a secret, underground facility. Using a library of alien knowledge that was uncovered early in the 21st century—code name: The Quantum Guide—these future astronauts prepare for the day when they will set out to colonize the galaxy. They must learn to decode the myriad of enigmas that exist in the great beyond if there is to be any hope of the human race becoming an interstellar power.
Curiosity’s Revolutionary Experiments
Published on Dec 14, 2012
When the Rover Curiosity landed on Mars, space and science fans all over the world rejoiced. But it is not there just to take pictures. This incredible piece of machinery is a one-ton, all-inclusive laboratory, capable of analyzing all aspects of the Martian surface and atmosphere.
It’s primary goals include investigation of the climate and geology, assessment of whether or not Gale Crater has ever offered life-sustaining environmental conditions, investigating the role of water on mars, and planetary habitability studies in preparation for future human exploration.
This video incorporates photography and video from the Mars Rover as well as CGI animations of the many components at work. Watch as Curiosity stretches its legs in preparation for the truly revolutionary experiments on its calendar for the weeks and years ahead.
Cosmic Journeys : Birth of a Black Hole
Published on Nov 29, 2012
It was one of the greatest mysteries in modern science: a series of brief but extremely bright flashes of ultra-high energy light coming from somewhere out in space. These gamma ray bursts were first spotted by spy satellites in the 1960s. It took three decades and a revolution in high-energy astronomy for scientists to figure out what they were.
Far out in space, in the center of a seething cosmic maelstrom. Extreme heat. High velocities. Atoms tear, and space literally buckles. Photons fly out across the universe, energized to the limits found in nature. Billions of years later, they enter the detectors of spacecraft stationed above our atmosphere. Our ability to record them is part of a new age of high-energy astronomy, and a new age of insights into nature at its most extreme. What can we learn by witnessing the violent birth of a black hole?
The outer limits of a black hole, call the event horizon, is subject to what Albert Einstein called frame dragging, in which space and time are pulled along on a path that leads into the black hole. As gas, dust, stars or planets fall into the hole, they form into a disk that spirals in with the flow of space time, reaching the speed of light just as it hits the event horizon. The spinning motion of this so-called “accretion disk” can channel some of the inflowing matter out into a pair of high-energy beams, or jets.
How a jet can form was shown in a supercomputer simulation of a short gamma ray burst. It was based on a 40-millisecond long burst recorded by Swift on May 9, 2005. It took five minutes for the afterglow to fade, but that was enough for astronomers to capture crucial details. It had come from a giant galaxy 2.6 billion light years away, filled with old stars.
Scientists suspected that this was a case of two dead stars falling into a catastrophic embrace. Orbiting each other, they moved ever closer, gradually gaining speed. At the end of the line, they began tearing each other apart, until they finally merged. NASA scientists simulated the final 35 thousandths of a second, when a black hole forms.
Chaos reigns. But the new structure becomes steadily more organized, and a magnetic field takes on the character of a jet. Within less than a second after the black hole is born, it launches a jet of particles to a speed approaching light.
A similar chain of events, in the death of a large star, is responsible for longer gamma ray bursts. Stars resist gravity by generating photons that push outward on their enormous mass. But the weight of a large star’s core increases from the accumulation of heavy elements produced in nuclear fusion. In time, its outer layers cannot resist the inward pull… and the star collapses. The crash produces a shock wave that races through the star and obliterates it.
In the largest of these dying stars, known as collapsars or hypernovae, a black hole forms in the collapse. Matter flowing in forms a disk. Charged particles create magnetic fields that twist off this disk, sending a portion out in high-speed jets.
Simulations show that the jet is powerful enough to plow its way through the star. In so doing, it may help trigger the explosion. The birth of a black hole does not simply light up the universe. It is a crucial event in the spread of heavy elements that seed the birth of new solar systems and planets.
But the black hole birth cries that we can now register with a fleet of high-energy telescopes are part of wider response to gravity’s convulsive power.
Earth-sized Planet Found Orbiting the Sun’s Nearest Neighbor
Published on Oct 18, 2012
European astronomers have discovered a planet with about the mass of the Earth orbiting a star in the Alpha Centauri system — the nearest to Earth. It is also the lightest exoplanet ever discovered around a star like the Sun.
Alpha Centauri is one of the brightest stars in the southern skies and is the nearest stellar system to our Solar System — only 4.3 light-years away. It is actually a triple star — a system consisting of two stars similar to the Sun orbiting close to each other, designated Alpha Centauri A and B, and a more distant and faint red component known as Proxima Centauri. Since the nineteenth century astronomers have speculated about planets orbiting these bodies, the closest possible abodes for life beyond the Solar System, but searches of increasing precision had revealed nothing. Until now.
The European team detected the planet by picking up the tiny wobbles in the motion of the star Alpha Centauri B created by the gravitational pull of the orbiting planet . The effect is minute — it causes the star to move back and forth by no more than 51 centimetres per second (1.8 km/hour), about the speed of a baby crawling. This is the highest precision ever achieved using this method.
Alpha Centauri B is very similar to the Sun but slightly smaller and less bright. The newly discovered planet, with a mass of a little more than that of the Earth , is orbiting about six million kilometres away from the star, much closer than Mercury is to the Sun in the Solar System. The orbit of the other bright component of the double star, Alpha Centauri A, keeps it hundreds of times further away, but it would still be a very brilliant object in the planet’s skies.
The first exoplanet around a Sun-like star was found by the same team back in 1995 and since then there have been more than 800 confirmed discoveries, but most are much bigger than the Earth, and many are as big as Jupiter. The challenge astronomers now face is to detect and characterise a planet of mass comparable to the Earth that is orbiting in the habitable zone around another star. The first step has now been taken.
Dark Matter Structure Revealed
Published on Oct 16, 2012
From HubbleCast and host Dr. J. Astronomers using the NASA/ESA Hubble Space Telescope have studied a giant filament of dark matter in 3D for the first time. Extending 60 million light-years from one of the most massive galaxy clusters known, the filament is part of the cosmic web that constitutes the large-scale structure of the Universe, and is a leftover of the very first moments after the Big Bang.
The theory of the Big Bang predicts that variations in the density of matter in the very first moments of the Universe led the bulk of the matter in the cosmos to condense into a web of tangled filaments. This view is supported by computer simulations of cosmic evolution, which suggest that the Universe is structured like a web, with long filaments that connect to each other at the locations of massive galaxy clusters. However, these filaments, although vast, are made mainly of dark matter, which is incredibly difficult to observe.
The first convincing identification of a section of one of these filaments was made earlier this year. Now a team of astronomers has gone further by probing a filament’s structure in three dimensions. Seeing a filament in 3D eliminates many of the pitfalls that come from studying the flat image of such a structure.
The team combined high resolution images of the region around the massive galaxy cluster MACS J0717.5+3745 (or MACS J0717 for short), taken using Hubble, NAOJ’s Subaru Telescope and the Canada-France-Hawaii Telescope, with spectroscopic data on the galaxies within it from the WM Keck Observatory and the Gemini Observatory. Analysing these observations together gives a complete view of the shape of the filament as it extends out from the galaxy cluster almost along our line of sight.
Theories of cosmic evolution suggest that galaxy clusters form where filaments of the cosmic web meet, with the filaments slowly funnelling matter into the clusters. Albert Einstein’s famous theory of general relativity says that the path of light is bent when it passes through or near objects with a large mass. Filaments of the cosmic web are largely made up of dark matter  which cannot be seen directly, but their mass is enough to bend the light and distort the images of galaxies in the background, in a process called gravitational lensing. The team has developed new tools to convert the image distortions into a mass map.
Gravitational lensing is a subtle phenomenon, and studying it needs detailed images. Hubble observations let the team study the precise deformation in the shapes of numerous lensed galaxies. This in turn reveals where the hidden dark matter filament is located.
Hubble’s observations of the cluster give the best two-dimensional map yet of a filament, but to see its shape in 3D required additional observations. Colour images , as well as galaxy velocities measured with spectrometers, using data from the Subaru, CFHT, WM Keck, and Gemini North telescopes (all on Mauna Kea, Hawaii), allowed the team to locate thousands of galaxies within the filament and to detect the motions of many of them.
A model that combined positional and velocity information for all these galaxies was constructed and this then revealed the 3D shape and orientation of the filamentary structure. As a result, the team was able to measure the true properties of this elusive filamentary structure without the uncertainties and biases that come from projecting the structure onto two dimensions, as is common in such analyses.
The results obtained push the limits of predictions made by theoretical work and numerical simulations of the cosmic web. With a length of at least 60 million light-years, the MACS J0717 filament is extreme even on astronomical scales. And if its mass content as measured by the team can be taken to be representative of filaments near giant clusters, then these diffuse links between the nodes of the cosmic web may contain even more mass (in the form of dark matter) than theorists predicted. So much that more than half of all the mass in the Universe may be hidden in these structures.
Why Mars Died, and Earth Lived
Published on Oct 13, 2012
This video explores the most basic question of all: why we explore space? Be sure to experience the visual spectacle in full HD, 1080P.
The Mars rover, Curiosity, is the latest in a long line of missions to Mars: landers sent to scoop its soil and study its rocks, orbiters sent to map its valleys and ridges.
They are all asking the same question. Did liquid water once flow on this dry and dusty world? Did it support life in any form? And are there remnants left to find? The science that comes out of these missions may help answer a much larger, more philosophical question.
Is our planet Earth the norm, in a galaxy run through with life-bearing planets? Or is Earth a rare gem, with a unique make-up and history that allowed it to give rise to living things? On Mars, Curiosity has spotted pebbles and other rocks commonly associated with flowing water.
It found them down stream on what appears to be an ancient river fan, where water flowed down into Gale Crater. This shows that at some point in the past, Mars had an atmosphere, cloudy skies, and liquid water flowing. So what could have turned it into the desolate world we know today?
One process that very likely played a role goes by the unscientific name, “sputtering.” Like the other planets in our solar system, Mars is lashed by high-energy photons from the Sun. When one of these photons enters the atmosphere of a planet, it can crash into a molecule, knocking loose an electron and turning it into an ion. The solar wind brings something else: a giant magnetic field. When part of the field grazes the planet, it can attract ions and launch them out into space.
Another part might fling ions right into the atmosphere at up to a thousand kilometers per second. The ions crash into other molecules, sending them in all directions like balls in a game of pool. Over billions of years, this process could have literally stripped Mars of its atmosphere, especially in the early life of the solar system when the solar wind was more intense than it is today.
Sputtering has actually been spotted directly on another dead planet, Venus. The Venus Express mission found that solar winds are steadily stripping off lighter molecules of hydrogen and oxygen. They escape the planet on the night side… then ride solar breezes on out into space.
This process has left Venus with an atmosphere dominated by carbon dioxide gas… a heat trapping compound that has helped send surface temperatures up to around 400 degrees Celsius. The loss of Venus’ atmosphere likely took place over millions of years, especially during solar outbursts known as coronal mass ejections.
If these massive blast waves stripped Venus and Mars of an atmosphere capable of supporting life how did Earth avoid the same grim fate? We can see the answer as the solar storm approaches earth. Our planet has what Mars and Venus lack – a powerful magnetic field generated deep within its core.
This protective shield deflects many of the high-energy particles launched by the Sun. In fact, that’s just our first line of defense. Much of the solar energy that gets through is reflected back to space by clouds, ice, and snow.
The energy that earth absorbs is just enough to power a remarkable planetary engine: the climate. It’s set in motion by the uneveness of solar heating, due in part to the cycles of day and night, and the seasons. That causes warm, tropical winds to blow toward the poles, and cold polar air toward the equator.
Wind currents drive surface ocean currents. This computer simulation shows the Gulf Stream winding its way along the coast of North America. This great ocean river carries enough heat energy to power the industrial world a hundred times over.
It breaks down in massive whirlpools that spread warm tropical waters over northern seas. Below the surface, they mix with cold deep currents that swirl around undersea ledges and mountains. Earth’s climate engine has countless moving parts: tides and terrain, cross winds and currents — all working to equalize temperatures around the globe.
Over time, earth developed a carbon cycle and an effective means of regulating green house gases. In our galaxy, are still-born worlds like Mars the norm? Or in Earth, has Nature crafted a prototype for its greatest experiment… Life?
Astronomers Spot Sudden Black Hole Flare Up
Published on Oct 5, 2012
Astronomers using NASA’s Swift satellite recently detected a rise in high-energy X-rays from a source toward the center of our Milky Way galaxy. The outburst, produced by a rare X-ray nova, came from a previously unknown stellar-mass black hole.
An X-ray nova is a short-lived X-ray source that appears suddenly, reaches its emission peak in a few days and then fades out over a period of months. The outburst arises when a torrent of stored gas suddenly rushes toward one of the most compact objects known, either a neutron star or a black hole.
The rapidly brightening source triggered Swift’s Burst Alert Telescope twice on the morning of Sept. 16, and once again the next day. Named Swift J1745-26 after the coordinates of its sky position, the nova is located a few degrees from the center of our galaxy toward the constellation Sagittarius. While astronomers do not know its
precise distance, they think the object resides about 20,000 to 30,000 light-years away in the galaxy’s inner region.
Ground-based observatories detected infrared and radio emissions, but thick clouds of obscuring dust have prevented astronomers from catching Swift J1745-26 in visible light.
Giant Telescopes of the Future
Published on Oct 5, 2012
Astronomy is big science. It’s a vast Universe out there, and the exploration of the cosmos requires huge instruments.
This is the 5-meter Hale reflector on Palomar Mountain. When the European Southern Observatory came into being, fifty years ago, it was the largest telescope in the world.
ESO’s Very Large Telescope at Cerro Paranal is the state of the art now. As the most powerful observatory in history, it has revealed the full splendor of the Universe in which we live.
But astronomers have set their sights on even bigger instruments.
And ESO is realizing their dreams.
San Pedro de Atacama. Tucked amidst breathtaking scenery and natural wonders, this picturesque town is home to indigenous Atacameños and adventurous backpackers alike. Not far from San Pedro, ESO’s first dream machine is taking shape.
It’s called ALMA — the Atacama Large Millimeter/submillimeter Array.
Close together, the 66 antennas provide a wide-angle view. But spread apart, they reveal much finer detail over a smaller area of sky.
At submillimeter wavelengths, ALMA sees the Universe in a different light. But what will it reveal?
The birth of the very first galaxies in the Universe, in the wake of the Big Bang.
Cold and dusty clouds of molecular gas — the stellar nurseries where new suns and planets are born.
And: the chemistry of the cosmos. ALMA will track down organic molecules — the building blocks of life.
At 5000 meters above sea level, the array provides an unprecedented view of the microwave Universe.
While ALMA is nearly completed, ESO’s next dream machine is still a few years away. See that mountain over there? That’s Cerro Armazones.
Not far from Paranal, it will be home to the largest telescope in the history of mankind. Meet the European Extremely Large Telescope. The world’s biggest eye on the sky.
Sporting a mirror almost forty meters across, the E- ELT simply dwarfs every telescope that preceded it. Almost eight hundred computer-controlled mirror segments. Complex optics to provide the sharpest possible images. A dome as tall as a church steeple.
The E-ELT is an exercise in superlatives. But the real wonder, or course, is in the Universe out there. The E-ELT will reveal planets orbiting other stars. Its spectrographs will sniff the atmospheres of these alien worlds, looking for bio-signatures.
Further away, the E-ELT will study individual stars in other galaxies.
It’s like meeting the inhabitants of neighboring cities for the first time.
Working as a cosmic time machine, the giant telescope lets us look back billions of years, to learn how everything began. And it may solve the riddle of the accelerating Universe — the mysterious fact that galaxies are pushed away from each other faster and faster.
What an Astronaut’s Camera Sees at Night (from ISS)
Published on Oct 1, 2012
Featuring the haunting, ethereal music of Axial Ensemble, title track “Premonition.” Aboard the ISS, we fly along over Earth’s luminous nocturnal landscapes, with Dr. Justin Wilkinson as our guide. This intimate tour takes us over cities and coastlines in the Americas, the Middle East and Europe.
Cosmic Journeys : The Largest Black Holes in the Universe
Published on Sep 26, 2012
Our Milky Way may harbor millions of black holes… the ultra dense remnants of dead stars. But now, in the universe far beyond our galaxy, there’s evidence of something far more ominous. A breed of black holes that has reached incomprehensible size and destructive power. Just how large, and violent, and strange can they get?
A new era in astronomy has revealed a universe long hidden to us. High-tech instruments sent into space have been tuned to sense high-energy forms of light — x-rays and gamma rays — that are invisible to our eyes and do not penetrate our atmosphere. On the ground, precision telescopes are equipped with technologies that allow them to cancel out the blurring effects of the atmosphere. They are peering into the far reaches of the universe, and into distant caldrons of light and energy. In some distant galaxies, astronomers are now finding evidence that space and time are being shattered by eruptions so vast they boggle the mind.
We are just beginning to understand the impact these outbursts have had on the universe: On the shapes of galaxies, the spread of elements that make up stars and planets, and ultimately the very existence of Earth. The discovery of what causes these eruptions has led to a new understanding of cosmic history. Back in 1995, the Hubble space telescope was enlisted to begin filling in the details of that history. Astronomers selected tiny regions in the sky, between the stars. For days at a time, they focused Hubble’s gaze on remote regions of the universe.
These hubble Deep Field images offered incredibly clear views of the cosmos in its infancy. What drew astronomers’ attention were the tiniest galaxies, covering only a few pixels on Hubble’s detector. Most of them do not have the grand spiral or elliptical shapes of large galaxies we see close to us today.
Instead, they are irregular, scrappy collections of stars. The Hubble Deep Field confirmed a long-standing idea that the universe must have evolved in a series of building blocks, with small galaxies gradually merging and assembling into larger ones.
Cosmic Journeys : The Most Powerful Objects in the Universe
Published on Sep 23, 2012
All across the immense reaches of time and space, energy is being exchanged, transferred, released, in a great cosmic pinball game we call our universe.
How does energy stitch the cosmos together, and how do we fit within it? We now climb the power scales of the universe, from atoms, nearly frozen to stillness, to Earth’s largest explosions. From stars, colliding, exploding, to distant realms so strange and violent they challenge our imaginations. Where will we find the most powerful objects in the universe?
Today, energy is very much on our minds as we search for ways to power our civilization and serve the needs of our citizens. But what is energy? Where does it come from? And where do we stand within the great power streams that shape time and space?
Energy comes from a Greek word for activity or working. In physics, it’s simply the property or the state of anything in our universe that allows it to do work. Whether it’s thermal, kinetic, electro-magnetic, chemical, or gravitational.
The 19th century German scientist Hermann von Helmholtz found that all forms of energy are equivalent, that one form can be transformed into any other. The laws of physics say that in a closed system – such as our universe – energy is conserved. It may be converted, concentrated, or dissipated, but it’s never lost.
James Prescott Joule built an apparatus that demonstrated this principle. It had a weight that descended into water and caused a paddle to rotate. He showed that the gravitational energy lost by the weight is equivalent to heat gained by the water from friction with the paddle. That led to one of several basic energy yardsticks, called a joule. It’s the amount needed to lift an apple weighing 100 grams one meter against the pull of Earth’s gravity.
In case you were wondering, it takes about one hundred joules to send a tweet, so tweeted a tech from Twitter. The metabolism of an average sized person, going about their day, generates about 100 joules a second, or 100 watts, the equivalent of a 100-watt light bulb.
In vigorous exercise, the power output of the body goes up by a factor of ten, one order of magnitude, to around a thousand joules per second, or a thousand watts. In a series of leaps, by additional factors of ten, we can explore the full energy spectrum of the universe.
Cosmic Journeys : When Will Time End?
Published on Sep 20, 2012
The answer to this question may depend on whether Stephen Hawking was right in his theory that describes how black holes shed mass and eventually decay. Time is flying by on this busy, crowded planet as life changes and evolves from second to second. At the same time, the arc of the human lifespan is getting longer: 67 years is the global average, up from just 20 years in the Stone Age.
Modern science provides a humbling perspective. Our lives, indeed even that of the human species, are just a blip compared to the Earth, at 4.5 billion years and counting, and the universe, at 13.7 billion years.
It now appears the entire cosmos is living on borrowed time. It may be a blip within a much grander sweep of time. When, we now ask, will time end?
Our lives are governed by cycles of waking and sleeping, the seasons, birth and death. Understanding time in cyclical terms connects us to the natural world, but it does not answer the questions of science.
What explains Earth’s past, its geological eras and its ancient creatures? And where did our world come from? How and when will it end? In the revolutions spawned by Copernicus and Darwin, we began to see time as an arrow, in a universe that’s always changing.
The 19th century physicist, Ludwig Boltzmann, found a law he believed governed the flight of Time’s arrow. Entropy, based on the 2nd law of thermodynamics, holds that states of disorder tend to increase.
From neat, orderly starting points, the elements, living things, the earth, the sun, the galaxy. are all headed eventually to states of high entropy or disorder. Nature fights this inevitable disintegration by constantly reassembling matter and energy into lower states of entropy in cycles of death and rebirth.
Will entropy someday win the battle and put the breaks on time’s arrow? Or will time, stubbornly, keep moving forward?
We are observers, and pawns, in this cosmic conflict. We seek mastery of time’s workings, even as the clock ticks down to our own certain end. Our windows into the nature of time are the mechanisms we use to chart and measure a changing universe, from the mechanical clocks of old, to the decay of radioactive elements, or telescopes that measure the speed of distant objects.
Our lives move in sync with the 24-hour day, the time it takes the Earth to rotate once. Well, it’s actually 23 hours, 56 minutes and 4.1 seconds if you’re judging by the stars, not the sun. Earth got its spin at the time of its birth, from the bombardment of rocks and dust that formed it. But it’s gradually losing it to drag from the moon’s gravity.
Cosmic Journeys : How Large is the Universe?
Published on Sep 18, 2012
The universe has long captivated us with its immense scales of distance and time. How far does it stretch? Where does it end, and what lies beyond its star fields and streams of galaxies extending as far as telescopes can see?
These questions are beginning to yield to a series of extraordinary new lines of investigation and technologies that are letting us to peer into the most distant realms of the cosmos. But also at the behavior of matter and energy on the smallest of scales. Remarkably, our growing understanding of this kingdom of the ultra-tiny, inside the nuclei of atoms, permits us to glimpse the largest vistas of space and time. In ancient times, most observers saw the stars as a sphere surrounding the earth, often the home of deities. The Greeks were the first to see celestial events as phenomena, subject to human investigation rather than the fickle whims of the Gods.
One sky-watcher, for example, suggested that meteors are made of materials found on Earth… and might have even come from the Earth. Those early astronomers built the foundations of modern science. But they would be shocked to see the discoveries made by their counterparts today. The stars and planets that once harbored the gods are now seen as infinitesimal parts of a vast scaffolding of matter and energy extending far out into space.
Just how far began to emerge in the 1920s. Working at the huge new 100-inch Hooker Telescope on California’s Mt. Wilson, astronomer Edwin Hubble, along with his assistant named Milt Humason, analyzed the light of fuzzy patches of sky… known then as nebulae.
They showed that these were actually distant galaxies far beyond our own. Hubble and Humason discovered that most of them are moving away from us. The farther out they looked, the faster they were receding. This fact, now known as Hubble’s law, suggests that there must have been a time when the matter in all these galaxies was together in one place.
That time, when our universe sprung forth, has come to be called the Big Bang. How large the cosmos has gotten since then depends on how long its been growing and its expansion rate. Recent precision measurements gathered by the Hubble space telescope and other instruments have brought a consensus…
That the universe dates back 13.7 billion years. Its radius, then, is the distance a beam of light would have traveled in that time … 13.7 billion light years. That works out to about 1.3 quadrillion kilometers. In fact, it’s even bigger…. Much bigger. How it got so large, so fast, was until recently a deep mystery.
That the universe could expand had been predicted back in 1917 by Albert Einstein, except that Einstein himself didn’t believe it until he saw Hubble and Humason’s evidence. Einstein’s general theory of relativity suggested that galaxies could be moving apart because space itself is expanding.
So when a photon gets blasted out from a distant star, it moves through a cosmic landscape that is getting larger and larger, increasing the distance it must travel to reach us. In 1995, the orbiting telescope named for Edwin Hubble began to take the measure of the universe… by looking for the most distant galaxies it could see.
Taking the expansion of the universe into account, the space telescope found galaxies that are now almost 46 billion light years away from us in each direction… and almost 92 billion light years from each other. And that would be the whole universe… according to a straightforward model of the big bang. But remarkably, that might be a mere speck within the universe as a whole, according to a dramatic new theory that describes the origins of the cosmos.
Finding Another Earth Within Reach
Published on Sep 17, 2012
From EsoCast. Planet hunters unveil the tricks of the trade for finding planets around nearby stars and scanning them for signs of life.
Are we alone? It’s the biggest question ever. And the answer is almost within reach. With so many galaxies, and each with so many stars, how could the Earth be unique?
In 1995, Swiss astronomers Michel Mayor and Didier Queloz were the first to discover an exoplanet orbiting a normal star. Since then, planet hunters have found many hundreds of alien worlds. Large and small, hot and cold, and in a wide variety of orbits. Now, we’re on the brink of discovering Earth’s twin sisters. And in the future: a planet with life — the Holy Grail of astrobiologists.
Michel Mayor’s team found hundreds of them from Cerro La Silla, ESO’s first Chilean foothold. Here’s the CORALIE spectrograph, mounted on the Swiss Leonhard Euler Telescope. It measures the tiny wobbles of stars, caused by the gravity of orbiting planets.
ESO’s venerable 3.6-metre telescope is also hunting for exoplanets. The HARPS spectrograph is the most accurate in the world. So far, it has discovered more than 150 planets. Its biggest trophy: a rich system containing at least five and maybe as many as seven alien worlds. But there are other ways to find exoplanets. In 2006, the 1.5-metre Danish telescope helped to discover a distant planet that is just five times more massive than the Earth.
The trick? Gravitational microlensing.?The planet and its parent star passed in front of a brighter star in the background, magnifying its image. And in some cases, you can even capture exoplanets on camera.
In 2004 NACO, the adaptive optics camera on the Very Large Telescope took the first image ever of an exoplanet. The red dot in this image is a giant planet orbiting a brown dwarf star. In 2010, NACO went one step further. This star is 130 light-years away from Earth.? It is younger and brighter than the Sun, and four planets circle around it in wide orbits.
NACO’s eagle-eyed vision made it possible to measure the light of planet c — a gas giant ten times more massive than Jupiter. Despite the glare of the parent star, the feeble light of the planet could be stretched out into a spectrum, revealing details about the atmosphere.
Today, many exoplanets are discovered when they transit across their parent stars. If we happen to see the planet’s orbit edge-on, it will pass in front of its star every cycle. Thus, tiny, regular brightness dips in the light of a star betray the existence of an orbiting planet. The TRAPPIST telescope at La Silla will help search for these elusive transits.
Meanwhile, the Very Large Telescope has studied a transiting planet in exquisite detail. Meet GJ1214b, a super-Earth 2.6 times larger than our home planet.
During transits, the planet’s atmosphere partly absorbs the light of the parent star. ESO’s sensitive FORS spectrograph revealed that GJ1214b might well be a hot and steamy sauna world.
Gas giants and sauna worlds are inhospitable to life. But the hunt is not over yet. Soon, the new SPHERE instrument will be installed at the VLT. SPHERE will be able to spot faint planets in the glare of their host stars. In 2016, the ESPRESSO spectrograph will arrive at the VLT and greatly surpass the current HARPS instrument.
And ESO’s Extremely Large Telescope, once completed, may well find evidence for alien biospheres. On Earth, life is abundant. Northern Chile offers its share of condors, vicuñas, vizcachas and giant cacti. Even the arid soil of the Atacama desert teems with hardy microbes.
We’ve found the building blocks of life in interstellar space. We’ve learnt that planets are abundant. Billions of years ago, comets brought water and organic molecules to Earth. Wouldn’t we expect the same thing to happen elsewhere?
Blue-Flame Plasma on the Face of the Sun
Published on Jun 11, 2012
From NASA’s Scientific Visualization Studio. This video takes images from the Solar Dynamics Observatory and applies additional processing to enhance the structures that are visible. The result is a beautiful, new way of looking at the sun. The original frames are in the 171 Angstrom wavelength of extreme ultraviolet. This wavelength shows plasma in the solar atmosphere, called the corona, that is around 600,000 Kelvin. The loops represent plasma held in place by magnetic fields. They are concentrated in “active regions” where the magnetic fields are the strongest. These active regions usually appear in visible light as sunspots. The events in this video represent 24 hours of activity on September 25, 2011.
Milky Way Versus Andromeda As Seen from Earth
Published on Jun 4, 2012
From HubbleCast. Scientists have been using Hubble observations to predict the future of the Andromeda Galaxy and the Milky Way, and how the collision will look from Earth. Projecting the motion of Andromeda’s stars over the next 8 billion years, the astronomers now know the path that galaxy is taking through space. And it’s heading straight for us! Computer simulations based on Hubble observations show how the two galaxies will crash together in around 4 billion years’ time.
The Andromeda Galaxy, some 2.2 million light-years away, is the closest spiral galaxy to our home, the Milky Way. For around a century, astronomers have known it is moving towards us, but whether or not the two galaxies would actually collide, or simply fly past each other, remained unclear. Now, a team of astronomers has used the Hubble Space Telescope to shed light on this question, by looking at the motion stars in the Andromeda Galaxy.
We wanted to figure out how Andromeda was moving through space. So in order to do that we measured the location of the Andromeda stars relative to the background galaxies. In 2002 they were in one place, and in 2010 they were in a slightly different place. And that allowed us to measure the motion over a period of eight years.
The motion is actually incredibly subtle, and not obvious to the human eye, even when looking at Hubble’s sharp images. However, sophisticated image analysis revealed tiny movements that the scientists were able to project into the future.
Based on these findings, it is finally possible to show what will happen to the Milky Way over the next eight billion years, as the galaxies drift closer, then collide and gradually merge into a single, larger, elliptical galaxy with reddish stars. And yet the Solar System should in fact survive this huge crash.
The reason we think that our Solar System will not be much affected by this collision between the Milky Way and Andromeda is that galaxies are mostly empty space.
Even though our galaxy, as well as the Andromeda Galaxy, has a hundred billion stars in it, they are very far apart. So if two galaxies actually collide with each other, the stars basically pass right between each other and the chance of two stars directly hitting each other is really, really small. So the likelihood that our Solar System will be directly impacted by another star, for example, in Andromeda as we collide with it is really, really small.
Well, if life is still present on Earth when this happens, the changes in the sky will be quite spectacular. Now they will be very very slow because the timescales on the scales of galaxies in the Universe are very very long. So you have to think, millions of years but even then over these timescales over millions of years, we will see big changes. If we wait a few billion years, Andromeda will be huge on the sky. It will be as big as our Milky Way because we’ll be very close to it.
And then later, when the galaxies merge, the merged remnant of the Milky Way Galaxy and Andromeda will look more like an elliptical galaxy and we’ll be sitting right in it.
So the view of the Milky Way on the night sky will be completely gone and this band of light will be replaced by a more spheroidal distribution of light.
And so, the Sun, born in the Milky Way almost 5 billion years ago will end its life in a new orbit, as part of a new galaxy.
Cosmic Journeys : The Incredible Journey of Apollo 12
Published on May 28, 2012
It’s the ultimate buddy movie, with two astronauts hitting the road and landing on the moon.
Earth. November 14, 1969. Three astronauts, with spacesuits, food, water, and a battery of scientific and communications equipment, prepared to fly to the moon. Thousands gathered at the Kennedy Space Center in Florida, including President and Mrs. Richard Nixon, to witness the historic launch. It was raining that day, but that was no cause for delay. The ship that would carry them into space was designed to launch in any weather.
But how would it respond to a powerful electrical storm now gathering above the launch pad? That was just the beginning of the incredible journey of Apollo 12.
With three astronauts fastened into their seats, the countdown proceeded. Astronaut and Mission Commander Pete Conrad would say later: “The flight was extremely normal, for the first 36 seconds.” The five engines of the Saturn 5’s huge first stage were designed to burn through 5 million pounds of liquid oxygen in just two and a half minutes, and to send the spacecraft up 67 kilometers above the Atlantic Ocean.
When it reached an altitude of 2000 meters, something unexpected happened. Racing through the stormy environment, the rocket generated a lightning bolt that traveled down its highly conductive exhaust trail.
Another bolt hit 16 seconds later. All of the spacecraft’s circuit breakers shut off. The tracking system was lost. A young flight controller in Houston, Texas instructed astronaut Alan Bean on how to turn on an auxiliary power system. The mission was back on track. Once in Earth orbit, all systems appeared to check out, and flight control officials gave the crew the green light to leave Earth.
The astronauts were not told of concern that the lighting strikes had damaged the pyrotechnic system used to deploy the parachutes that would ease them back through the Earth’s atmosphere. If that system failed, the astronauts would not return alive.
This mission would have its share of perils, not unlike those faced by a long line of past explorers, whose courage and restless spirit propelled them into the unknown. This one, however, was backed by years of technology development, test flights, astronaut training, and the largest support team back home that any mission ever had.
But hundreds of thousands of kilometers out in space the three astronauts were pretty much on their own. What made Apollo 12 unique was the friendship and chemistry of its crew. Conrad, Bean, and Richard Gordon were all Navy men. Working and training together on the Gemini program, they had gained each other’s respect and trust.
Now, hurtling across more than 400,000 kilometers to the moon, they prepared to fullfill the mission’s goals. One was to set up a scientific station designed to record seismic, atmospheric, and solar data.
Another was to visit an unmanned lunar probe called Surveyor III that had landed there two and a half years before. The idea was to bring back a part to study the effect of the lunar environment.
A third goal was to improve on the landing of Apollo 11 just 5 months before. Dropping down over a region called the Sea of Tranquility, pilot Neil Armstrong found himself heading straight for a crater full of boulders. He had to fly over the planned landing site and find a new one. Now kilometers beyond the target, the lander, called Eagle, was literally running out of gas.
With less than 30 seconds of fuel left, Neil Armstrong and Buzz Aldrin finally touched down on a landscape obscured by dust stirred up by the vehicle’s thrusters. Future astronauts would have to be able to make precision landings at locations dictated by science. That meant they would have to touch down on landscapes filled with all kinds of rocks and craters.
For Apollo 12, the science pointed to a region known as the Ocean of Storms, some 2000 kilometers from where the Eagle had landed. Here, the landscape is dark from lava that cooled to form its flat expanse billions of years ago.
How a Giant Telescope Works
Published on May 16, 2012
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From ESOcast, explore the state-of-the-art technology behind the Very Large telescope, which has provided astronomers with an unequalled view of the Universe. To obtain the sharpest images of the sky, the VLT has to cope with two major effects that distort the images of celestial objects. The first one is mirror deformations due to their large sizes. This problem is corrected using a computer-controlled support system — active optics — that ensures that the mirrors keep their desired shapes under all circumstances. The second effect is produced by Earth’s atmosphere, which makes stars appear blurry, even with the largest telescopes. Adaptive optics is a real-time correction of the distortions produced by the atmosphere using computer-controlled mirrors that deform hundreds of times per second to counteract the atmospheric effects.
As one demonstration of its power the VLT’s sensitive infrared cameras, helped by adaptive optics, have been able to peer through the massive dust clouds that block our view to Milky Way’s core. The images, taken over many years, have allowed astronomers to actually watch stars orbiting around the monstrous black hole that lies in the center of our galaxy. It was even possible to detect energetic flares from gas clouds falling into the black hole.
Tale of the Shepherd Planets
Published on Apr 24, 2012
Until recently, the search for planets beyond our solar system was a matter of calculating the odds and laying out theories of solar system formation. Circumstantial evidence began to trickle in, a color shift in a stars light as a planet tugged on it, or a dipping in its light as a planet passed in front.
When would our technology allow us to see through the bright light of stars to see these alien worlds directly? Scientists using the Hubble Space Telescope began examining a star visible in the southern hemisphere, just 25 light years away.
Called Fomalhaut, it’s much hotter than our sun and 15 times as bright. In fact, it’s one of the brightest stars in our night sky. What makes it so curious is the large ring of gas that surrounds it. The ring is slightly off center from the location of the sun. That suggests there’s a gravitational presence, a planet, that’s distorting its shape. With a coronagraph in place to block the star’s light, Hubble zeroed in on the ring. Right there in the data, it turns out, was a bump, perhaps a planet.
Hubble photographed this planet a second time, two years later when it had progressed in its orbit. Based on the change in position, astronomers calculated that it takes about 872 Earth-years to complete an orbit.
Astronomers thought it to be a huge planet, many times larger than Jupiter. The reason they could see is that it may have a very large and reflective ring system. From the ring’s narrow width, the planet seems to be sculpting it, by pushing on and sharpening its inner edge.
Hubble had delivered a rare direct image of an extrasolar planet, the first one ever in visible light. Astronomers could not confirm its presence by looking in the infrared portion of the light spectrum. That seemed to be the end of it.
Enter ALMA, the not quite completed Atacama Large Millimeter-Submillimeter Array in the high desert of Chile. It produced this picture of the disk, which showed that its inner and outer edges are both relatively sharp.
Computer simulations refined the parameters of planets. There is not one, but two, on both edges of the ring. They had to be relatively small to avoid destroying the ring: larger than Mars, but only a few times larger than Earth. There’s little chance that these frigid worlds harbor life. What they do is extend our vision, and our ideas on what it takes to form a solar system.
Narrowing the Search for Dark Matter
Published on Apr 5, 2012
Scientists have further narrowed the search for a hypothetical particle that could be dark matter, the mysterious stuff that makes up 80 percent of all the mass in the universe. This video from NASA Astrophysics presents the new results, compiled from two years’ worth of data from NASA’s Fermi Gamma-ray Space Telescope.
Gamma rays are very energetic light, and the telescope looks for faint gamma-ray signals that are generated by a variety of sources, such as gas and dust spiraling into supermassive black holes or exploding stars. But another potential source of gamma rays is dark matter. Although no one is sure what dark matter is, one of the leading candidates is a yet-to-be-discovered particle called a weakly interacting massive particle (WIMP). When two of these WIMPs meet, the theory goes, they can annihilate one another and generate gamma rays.
There are many possible versions of WIMPs, and they’re expected to span a wide range of masses, producing a range of gamma rays with different energies. Using Fermi, the scientists focused on 10 small galaxies that orbit the Milky Way, searching for gamma-ray signals within a specific range of energies. They found no signs of annihilating WIMPs, which rules out certain kinds of WIMPs as dark-matter candidates.
Wandering Stars: a tour of the planets
Published on Mar 1, 2012
A beauteous rip through the solar sytem, based on NASA’s Science on a Sphere program “The Wanderers.” In ancient times, humans watched the skies looking for clues to their future and to aid in their very survival. They soon observed that some stars were not fixed, but moved in the sky from night to night. They called these stars the wanderers.
At the center of our solar system is the sun, binding the planets with its gravitational pull. From our viewpoint on earth, the sun appears small in the sky, but in reality it dwarfs even Jupiter, the largest planet in the solar system.
The distance from the sun to the small worlds traveling it are vast. Light takes eight minutes to reach earth, and nearly a day to reach the farthest known bodies. Join us now as we tour our solar system, starting with sun-baked mercury and traveling to the remotest outskirts, where small, icy bodies move with only the faintest connection to our sun.
Mercury, the closest planet to Sun is also the smallest terrestrial planet. It orbits so swiftly that its year lasts only 88 Earth days. The airless cratered surface could almost be mistaken for our moon, relentlessly bombarded by meteoroids for four and a half billion years. One of these encounters left a giant scar called the golarus basin, one of the largest impact sights in the solar system. Temperatures on the surface of mercury can reach a blistering 800 degrees Fahrenheit, and can dip to 300 degrees below zero on the night side.
Venus, as seen from Earth, is the brightest object in sky after the Sun and Moon. Russian probes were the first to land on Venus in the 1970’s and 1980’s. Venus’s surface is volcanic. Its atmosphere is composed of thick, dense carbon dioxide with sulfuric acid clouds. Both are potent greenhouse gases that trap incoming sunlight. Venus rotates slowly—one Venusian day lasts almost four Earth months.
Earth is the only planet with life as we know it. The atmosphere and temperatures are “just right” for life. It is the only known body in our solar system where water can exist as a gas, liquid,
and solid. Vast oceans dominate surface of the planet. Seasonal changes occur on the surface. Earth has a solid surface that constantly shifts due to plate tectonics.
Once geologically active, Mars has the largest dormant volcano in the solar system, Olympus Mons. It also hast the longest valley in the solar system, called Valles Marineris. Mars has a thin, atmosphere primarily composed of carbon dioxide. Surface conditions are dynamic. Mars has seasons as well as massive dust storms that cover the planet. Its surface features include the smooth, low-lying northern hemisphere and the craggy, heavily-cratered southern uplands. Evidence suggests that Mars had water running on its surface at some time in the past.
The asteroid belt is composed of small rocky pieces. The big question is “What happened here?” and “Why no planets?” The asteroid Ceres is large enough to be classified as a dwarf planet.
Jupiter is the largest and most massive planet in the Solar System. It rotates rapidly, completing one rotation every 10 hours. Long-lasting, high-speed winds and storms dominate Jupiter’s atmosphere. Jupiter has a faint planetary ring system and over 63 moons. The largest moons, discovered by Galileo in 1610, vary widely.
Io is volcanically active. Europa’s cracked surface likely hides an ocean below. Ganymede is the largest moon in the Solar System. Callisto is heavily cratered.
Saturn’s seemingly serene atmosphere hides powerful storms and winds on its surface. Saturn is known for its extensive ring system made of chunks of ice, rock, and dust with small moonlets embedded within the rings. Saturn has more than 60 moons. Conditions vary among the moons.
Titan, the largest moon, has a thick, smoggy, atmosphere covering its icy surface with lakes of liquid methane or ethane. Small Enceladus has water and ice geysers at its south pole. Its water vapor coat other nearby moons and create a thin Saturn ring.
Uranus receives 400 times less sunlight than Earth. Uranus lies nearly sideways, making its axis nearly parallel to the plane of the Solar System. This extreme tilt give rise to seasons that last nearly 28 Earth years. Uranus as many moons and a faint ring system. It has only been visited by one spacecraft, Voyager 2, in 1986. Like the other giant planets, Uranus’s atmosphere is primarily hydrogen and helium with a trace of methane gas over deep clouds, giving it a pale blue-green tint.
Neptune also has many moons and a faint ring system. Its Great Dark Spot, a large storm with extremely strong winds, disappeared in the 1990s. Neptune’s vivid blue color is due to its frigid temperature: -371°F (-224 °C).
The Shrinking Expanding Moon
Uploaded on Feb 20, 2012
From NASA’s Scientific Visualization Studio. New images from NASA’s Lunar Reconnaissance Orbiter (LRO) spacecraft show the moon’s crust is being stretched, forming minute valleys in a few small areas on the lunar surface. Scientists propose this geologic activity occurred less than 50 million years ago, which is considered recent compared to the moon’s age of more than 4.5 billion years.
A team of researchers analyzing high-resolution images obtained by the Lunar Reconnaissance Orbiter Camera (LROC) show small, narrow trenches typically much longer than they are wide. This indicates the lunar crust is being pulled apart at these locations. These linear valleys, known as graben, form when the moon’s crust stretches, breaks and drops down along two bounding faults. A handful of these graben systems have been found across the lunar surface.
We think the moon is in a general state of global contraction because of cooling of a still hot interior,” said Thomas Watters of the Center for Earth and Planetary Studies at the Smithsonian’s National Air and Space Museum in Washington, and lead author of a paper on this research appearing in the March issue of the journal Nature Geoscience. “The graben tell us forces acting to shrink the moon were overcome in places by forces acting to pull it apart. This means the contractional forces shrinking the moon cannot be large, or the small graben might never form.”
The weak contraction suggests that the moon, unlike the terrestrial planets, did not completely melt in the very early stages of its evolution. Rather, observations support an alternative view that only the moon’s exterior initially melted forming an ocean of molten rock.
In August 2010, the team used LROC images to identify physical signs of contraction on the lunar surface, in the form of lobe-shaped cliffs known as lobate scarps. The scarps are evidence the moon shrank globally in the geologically recent past and might still be shrinking today. The team saw these scarps widely distributed across the moon and concluded it was shrinking as the interior slowly cooled.
Based on the size of the scarps, it is estimated that the distance between the moon’s center and its surface shank by approximately 300 feet. The graben were an unexpected discovery and the images provide contradictory evidence that the regions of the lunar crust are also being pulled apart.
“This pulling apart tells us the moon is still active,” said Richard Vondrak, LRO Project Scientist at NASA’s Goddard Space Flight Center in Greenbelt, Md. “LRO gives us a detailed look at that process.”
As the LRO mission progresses and coverage increases, scientists will have a better picture of how common these young graben are and what other types of tectonic features are nearby. The graben systems the team finds may help scientists refine the state of stress in the lunar crust.
“It was a big surprise when I spotted graben in the far side highlands,” said co-author Mark Robinson of the School of Earth and Space Exploration at Arizona State University, principal investigator of LROC. “I immediately targeted the area for high-resolution stereo images so we could create a three-dimensional view of the graben. It’s exciting when you discover something totally unexpected and only about half the lunar surface has been imaged in high resolution. There is much more of the moon to be explored.”
The Violent End Stage of Star Formation
Uploaded on Dec 15, 2011
EsoCast showcases a new Hubble image of a giant cloud of hydrogen gas illuminated by a bright young star. The image shows how violent the end stages of the star formation process can be, with the young object shaking up its stellar nursery.
A few thousand light-years away, in the constellation of Cygnus, lies the compact star-forming region Sh 2-106, or S106 for short. Despite the celestial colors of this picture, there is nothing peaceful about this scene. A young star, named S106 IR, is being born at the heart of the nebula. In the violent final stages of its formation, the star is ejecting material at high speed, violently disrupting the gas and dust. 3D visualizations show the extent to which the star has carved its surroundings into a complex shape. In particular, the hourglass-like structure of the nebula is a result of jets from the star slamming into the cloud of hydrogen it is forming from.
At the outer edges of these cavities, the gas has been compressed into shock fronts by the pressure. The star has a mass about 15 times that of the Sun and is in the final stages of its formation. It will soon quiet down by entering the adult stage of stellar life, known to astronomers as the main sequence.
For now, though, S106 IR remains embedded in its parent cloud, but it is rebelling against it. The material spewing off the star not only gives the cloud its hourglass shape but also makes the hydrogen gas turbulent. The resulting intricate patterns are clearly visible here.
As well as churning up the gas cloud, the young star is also heating it up to temperatures of 10 000 degrees Celsius. The star’s radiation excites the gas, making it glow like a fluorescent bulb. The light from this glowing gas is colored blue in this image, which combines Hubble observations taken in visible and infrared light.
Separating these regions of glowing gas is a cooler, thick stream of dust, shown here in red. This dark material almost completely hides the star from view, but the young object can still be seen faintly peeking through the widest part of the dust lane.
The cloud itself is relatively small by the standards of star- forming regions, around two light-years in size along its longest axis. This is about half the distance between the Sun and Proxima Centauri, our nearest stellar neighbor, making it far smaller than familiar star-forming regions like the Orion Nebula and Carina Nebula.
Black Hole Meltdown in the Galactic Center
Uploaded on Dec 14, 2011
Black hole extravaganza from ESOcast. Not long ago, watching something being ripped apart as it falls towards a giant black hole would be science fiction. This is now reality.
Observers under dark skies, far from the bright city lights, can marvel at the splendor of the Milky Way, arching in an imposing band across the sky. Zooming in towards the center of our galaxy, about 25000 light years away, you can see that it is composed of myriads of stars.
This is a pretty impressive sight, but much is hidden from view by interstellar dust, and astronomers need to look using a different wavelength, the infrared, that can penetrate the dust clouds. With large telescopes, astronomers can then see in detail the swarm of stars circling the supermassive black hole, in the same way that the Earth orbits the Sun.
The Galactic Center harbors the closest supermassive black hole known, and the one that is also the largest in terms of its angular diameter on the sky, making it the best choice for a detailed study of black holes.
This black hole’s mass is a hefty four million times that of the Sun, earning it the title of supermassive black hole. Although it is huge, this black hole is currently supplied with little material and is not shining brightly. But this is about to change.
Using ESO’s Very Large Telescope, a team of astronomers has discovered a new object that is heading almost straight towards the black hole at vertiginous speed. The object is not a star, but a cloud of gas.
“The cloud consists mainly of hydrogen gas, gas which we see anyhow in the galactic center all over the place. This particular cloud weighs more or less three times the mass of Earth. So it’s a rather small and tiny blob only, but it glows very brightly in the light of the stars which are surrounding it .”
As the astronomers watch, the cloud has been picking up pace as it gets closer to the giant black hole. Its speed has doubled in the last seven years and it is now speeding towards the black hole at more than 8 million kilometers per hour.
The astronomers have already seen the cloud’s outer layers becoming more and more disrupted over the last few years as it approaches the black hole. But the exciting part is yet to come.
“The Black hole, imagine it sitting here, has a tremendous gravitational force and the cloud, as it comes in, it will be elongated and stretched, it will become essentially like spaghetti. It will be elongated and falling into the black hole.”
“The next few years will be really fantastic and exciting because we are probing the territory. Here this cloud comes and gets disrupted, but now it will begin to interact with the hot gas right around the black hole. We have never seen this before.”
No one knows what will happen next. The cloud will probably heat up and may start to emit powerful X- rays as it gets disrupted. In the end the material will eventually disappear by falling into the black hole. For the scientists, this event is truly a unique chance to probe the hot gas around the black hole.
“But this process of how material gets into the black hole really is not clear to us we don’t understand it in any detail. And here in the galactic center we have an opportunity so to speak to have a probe of this process. How material really gets added to the black hole, and what the physical processes are, how the interactions happen in this very central region. That’s a fantastic opportunity.”
This is indeed science fiction becoming science fact.
What sets Curiosity apart from other Mars Rovers?
Uploaded on Dec 9, 2011
The Mars Science Lab was launched November 26, 2011, and is scheduled to land on Mars at Gale Crater on August 6, 2012. The rover Curiosity, after completing a more precise landing than ever attempted previously, is intended to help assess Mars’ habitability for future human missions. Its primary mission objective is to determine whether Mars is or has ever been an environment able to support life.
Curiosity is five times as large as either of the Mars Exploration Rovers Spirit or Opportunity and carries more than ten times the mass of scientific instruments present on the older vehicles. The rover is expected to operate for at least 686 days as it explores with greater range than any previous Mars rover. Here are some of the specs that help set Curiosity apart from the other rovers:
The rover Curiosity is 3 meters in length, and weighs 900 kg, including 80 kg worth of scientific instruments. It is approximately the size of a Mini Cooper automobile.
Once on the surface, Curiosity will be able to roll over obstacles approaching 75 cm high. Maximum terrain-traverse speed is estimated to be 90 meters per hour by automatic navigation, however, with average speeds likely to be about 30 meter per hour depending on power levels, difficulty of the terrain, slippage, and visibility. It is expected to traverse a minimum of 12 miles in its two-year mission.
Curiosity is powered by a radioisotope thermoelectric generator, as used by the successful Mars landers Viking 1 and Viking 2 in 1976. Radioisotope power systems are generators that produce electricity from the natural decay of plutonium-238, which is a non-fissile isotope of plutonium. Heat given off by the natural decay of this isotope is converted into electricity, providing constant power during all seasons and through the day and night, and waste heat can be used via pipes to warm systems, freeing electrical power for the operation of the vehicle and instruments.
The temperatures that Curiosity can encounter vary from +30 to −127 °C. Therefore, the Heat rejection system uses fluid pumped through 60 meters of tubing in the MSL body so that sensitive components are kept at optimal temperatures.
The two identical on-board computers contain radiation-hardened memory to tolerate the extreme radiation environment from space and to safeguard against power-off cycles. Curiosity has two means of communication — an X-band transmitter and receiver that can communicate directly with Earth, and a UHF software-defined radio for communicating with Mars orbiters. Communication with orbiters is expected to be the main method for returning data to Earth, since the orbiters have both more power and larger antennas than the lander. At landing time, 13 minutes, 46 seconds will be required for signals to travel between Earth and Mars.
Like previous rovers Mars Exploration Rovers and Mars Pathfinder, Curiosity is equipped with 6 wheels in a rocker-bogie suspension. The suspension system will also serve as landing gear for the vehicle. Its smaller predecessors used airbag-like systems. Curiosity’s wheels are significantly larger than those used on the previous rovers. Each wheel has a pattern of grooves that help it maintain traction, while leaving a distinctive track in Martian soil. That pattern, to be photographed by on-board cameras, will be used to judge the distance travelled.
Einstein’s Greatest Blunder
Uploaded on Dec 4, 2011
Excerpt from “Mysteries of a Dark Universe.” Albert Einstein sought to explain why the gravity of all the stars and gas out there didnt simply cause the universe to collapse into a heap. Following the discovery of the expanding universe, he admitted to the “greatest blunder” of his career.
Dwarf Planet Crossing at the Solar System’s Edge
Uploaded on Nov 8, 2011
From ESOCast. Astronomers have accurately measured the size of the remote dwarf planet Eris for the first time. They caught it as it passed in front of a faint star. Eris also seems to be extremely reflective, probably because it is covered in a thin layer of frozen atmosphere.
Occultations are rather like eclipses —the background star disappears behind the object and reappears on its other side. As viewed from Earth, the brightness of the background star suddenly drops and then returns equally suddenly to its previous level. By looking at these two events, astronomers can measure the size and shape of the occulting foreground object. If they also know the mass of this object they can then determine its density.
The occultation technique has now enabled astronomers to learn a lot more about the dwarf planet Eris. Eris was identified as a large object in the outer Solar System in 2005. Its discovery was one of the factors that led to the creation of a new class of objects called dwarf planets and the reclassification of Pluto from planet to dwarf planet in 2006.
Eris is three times farther from the Sun than Pluto at the moment, and until now was believed to be about 25% bigger. But the new observations show that Eris is in fact almost exactly the same size as Pluto, with a diameter of around 2330 kilometres.
Because Eris also has a moon, called Dysnomia, astronomers have also been able to calculate the mass of Eris by a careful study of this moon’s orbit. Using the new diameter and known mass, they then calculated the density of the Eris, which now appears to be greater than astronomers had previously thought. Eris seems to be a rocky body surrounded by a thick mantle of ice.
The dwarf planet turns out to reflect almost all of the light that falls on it — its surface is even brighter than fresh snow on Earth. Eris is probably covered in a very thin layer of frozen atmosphere that is likely to consist of frozen nitrogen mixed with methane. It is probably the result of the freezing of Eris’s atmosphere as the dwarf planet’s elongated orbit takes it far away from the Sun.
These important new observations, made with relatively small telescopes, have allowed astronomers to measure Eris’s properties better than ever before. This is another step towards understanding the mysterious objects that lie in the remote parts of our own Solar System.
Pulsar Enigma Discovered
Uploaded on Nov 6, 2011
From NASA Astrophysics. Hidden deep within a group of ancient stars, there lurks a young and powerful enigma. This is NGC 6624, a globular cluster near our galaxy’s center thought to be about 10 billion years old. NASA’s Fermi Gamma-ray Space Telescope detects high-energy radiation from many globular clusters.
Usually what Fermi is seeing is the cumulative gamma rays from all of the old pulsars in these clusters. A pulsar is a rapidly spinning neutron star, which is the small, incredibly dense remnant of a much more massive star.
A teaspoon of matter from a neutron star weighs as much Mount Everest, and a neutron star is so compact that a ball about 15 miles across contains more matter than our sun. Neutron stars spin between 7 and 40,000 times a minute and form with incredibly strong magnetic fields. Rapid spin and intense magnetic fields drive powerful beams of electromagnetic radiation, including gamma rays. As the pulsar rotates, these beams sweep the sky like a lighthouse.
To a distant observer, the pulsar appears to blink on and off. Pulsars slow down as they age but some of the oldest pulsars spin hundreds of times a second. Each of these millisecond pulsars orbits a normal star. Over time, the impact of gas pulled from the normal star, has spun the pulsar up to incredible speeds. This accretion may be the cause of their weaker magnetic fields.
Despite this, these pulsars also emit gamma rays. But the millisecond pulsar in NGC 6624 doesn’t fit neatly into this picture. It’s so bright that Fermi directly detects its gamma rays, and so far it’s the only one seen in a globular cluster with such power. It’s losing energy so fast that it must be only around 25 million years old–the youngest millisecond pulsar ever found. It also possesses the strongest magnetic field yet observed in a millisecond pulsar. It’s high energy output dooms it to fade out quickly on astronomical time scales and scientists wonder if this object represents a new way to make millisecond pulsars.
In three years, Fermi has detected more than 100 gamma-ray pulsars, shown here using animated pulses fifty slower than actual speed. Recent advances in data analysis helped Fermi reach this milestone, and these techniques promise to find many more gamma-ray pulsars. Some of these are historical –the first gamma-ray pulsars ever discovered. Others, like the pulsar in NGC 6624, were first seen by radio telescopes and then observed by Fermi. Some were first spotted in radio after investigating unknown sources detected by Fermi.
And about a third of gamma-ray pulsars were discovered by Fermi on the basis of their gamma-ray pulsations alone. Fermi’s gamma-ray observations are literally showing us these incredible stellar lighthouses in a new light.
Cosmic Journeys : Mysteries of a Dark Universe
Uploaded on Oct 13, 2011
Cosmology, the study of the universe as a whole, has been turned on its head by a stunning discovery that the universe is flying apart in all directions at an ever-increasing rate.
Is the universe bursting at the seams? Or is nature somehow fooling us?
The astronomers whose data revealed this accelerating universe have been awarded the Nobel Prize for Physics.
And yet, since 1998, when the discovery was first announced, scientists have struggled to come to grips with a mysterious presence that now appears to control the future of the cosmos: dark energy.
On remote mountaintops around the world, major astronomical centers hum along, with state of the art digital sensors, computers, air conditioning, infrastructure, and motors to turn the giant telescopes.
Deep in Chile’s Atacama desert, the Paranal Observatory is an astronomical Mecca.
This facility draws two megawatts of power, enough for around two thousand homes.
What astronomers get for all this is photons, tiny mass-less particles of light. They stream in from across time and space by the trillions from nearby sources, down to one or two per second from objects at the edge of the visible universe.
In this age of precision astronomy, observers have been studying the properties of these particles, to find clues to how stars live and die, how galaxies form, how black holes grow, and more.
But for all we’ve learned, we are finding out just how much still eludes our grasp, how short our efforts to understand the workings of the universe still fall.
A hundred years ago, most astronomers believed the universe consisted of a grand disk, the Milky Way. They saw stars, like our own sun, moving around it amid giant regions of dust and luminous gas.
The overall size and shape of this “island universe” appeared static and unchanging.
That view posed a challenge to Albert Einstein, who sought to explore the role that gravity, a dynamic force, plays in the universe as a whole.
There is a now legendary story in which Einstein tried to show why the gravity of all the stars and gas out there didn’t simply cause the universe to collapse into a heap.
He reasoned that there must be some repulsive force that countered gravity and held the Universe up.
He called this force the “cosmological constant.” Represented in his equations by the Greek letter Lambda, it’s often referred to as a fudge factor.
In 1916, the idea seemed reasonable. The Dutch physicist Willem de Sitter solved Einstein’s equations with a cosmological constant, lending support to the idea of a static universe.
Now enter the American astronomer, Vesto Slipher.
Working at the Lowell Observatory in Arizona, he examined a series of fuzzy patches in the sky called spiral nebulae, what we know as galaxies. He found that their light was slightly shifted in color.
It’s similar to the way a siren distorts, as an ambulance races past us.
If an object is moving toward Earth, the wavelength of its light is compressed, making it bluer. If it’s moving away, the light gets stretched out, making it redder.
12 of the 15 nebulae that Slipher examined were red-shifted, a sign they are racing away from us.
Edwin Hubble, a young astronomer, went in for a closer look. Using the giant new Hooker telescope in Southern California, he scoured the nebulae for a type of pulsating star, called a Cepheid. The rate at which their light rises and falls is an indicator of their intrinsic brightness.
By measuring their apparent brightness, Hubble could calculate the distance to their host galaxies.
Combining distances with redshifts, he found that the farther away these spirals are, the faster they are moving away from us. This relationship, called the Hubble Constant, showed that the universe is not static, but expanding.
Einstein acknowledged the breakthrough, and admitted that his famous fudge factor was the greatest blunder of his career.
Cosmic Journeys : The Riddle of AntiMatter
Uploaded on Aug 19, 2011
Explore one of the deepest mysteries about the origin of our universe. According to standard theory, the early moments of the universe were marked by the explosive contact between subatomic particles of opposite charge. Featuring short interviews with Masaki Hori, Tokyo University and Jeffrey Hangst, Aarhus University.
Scientists are now focusing their most powerful technologies on an effort to figure out exactly what happened. Our understanding of cosmic history hangs on the question: how did matter as we know it survive? And what happened to its birth twin, its opposite, a mysterious substance known as antimatter?
A crew of astronauts is making its way to a launch pad at the Kennedy Space Center in Florida. Little noticed in the publicity surrounding the close of this storied program is the cargo bolted into Endeavor’s hold. It’s a science instrument that some hope will become one of the most important scientific contributions of human space flight.
It’s a kind of telescope, though it will not return dazzling images of cosmic realms long hidden from view, the distant corners of the universe, or the hidden structure of black holes and exploding stars.
Unlike the great observatories that were launched aboard the shuttle, it was not named for a famous astronomer, like Hubble, or the Chandra X-ray observatory.
The instrument, called the Alpha Magnetic Spectrometer, or AMS. The promise surrounding this device is that it will enable scientists to look at the universe in a completely new way.
Most telescopes are designed to capture photons, so-called neutral particles reflected or emitted by objects such as stars or galaxies. AMS will capture something different: exotic particles and atoms that are endowed with an electrical charge. The instrument is tuned to capture “cosmic rays” at high energy hurled out by supernova explosions or the turbulent regions surrounding black holes. And there are high hopes that it will capture particles of antimatter from a very early time that remains shrouded in mystery.
The chain of events that gave rise to the universe is described by what’s known as the Standard model. It’s a theory in the scientific sense, in that it combines a body of observations, experimental evidence, and mathematical models into a consistent overall picture. But this picture is not necessarily complete.
The universe began hot. After about a billionth of a second, it had cooled down enough for fundamental particles to emerge in pairs of opposite charge, known as quarks and antiquarks. After that came leptons and antileptons, such as electrons and positrons. These pairs began annihilating each other.
Most quark pairs were gone by the time the universe was a second old, with most leptons gone a few seconds later. When the dust settled, so to speak, a tiny amount of matter, about one particle in a billion, managed to survive the mass annihilation.
That tiny amount went on to form the universe we can know – all the light emitting gas, dust, stars, galaxies, and planets. To be sure, antimatter does exist in our universe today. The Fermi Gamma Ray Space Telescope spotted a giant plume of antimatter extending out from the center of our galaxy, most likely created by the acceleration of particles around a supermassive black hole.
The same telescope picked up signs of antimatter created by lightning strikes in giant thunderstorms in Earth’s atmosphere. Scientists have long known how to create antimatter artificially in physics labs – in the superhot environments created by crashing atoms together at nearly the speed of light.
Here is one of the biggest and most enduring mysteries in science: why do we live in a matter-dominated universe? What process caused matter to survive and antimatter to all but disappear? One possibility: that large amounts of antimatter have survived down the eons alongside matter.
In 1928, a young physicist, Paul Dirac, wrote equations that predicted the existence of antimatter. Dirac showed that every type of particle has a twin, exactly identical but of opposite charge. As Dirac saw it, the electron and the positron are mirror images of each other. With all the same properties, they would behave in exactly the same way whether in realms of matter or antimatter. It became clear, though, that ours is a matter universe. The Apollo astronauts went to the moon and back, never once getting annihilated. Solar cosmic rays proved to be matter, not antimatter.
It stands to reason that when the universe was more tightly packed, that it would have experienced an “annihilation catastrophe” that cleared the universe of large chunks of the stuff. Unless antimatter somehow became separated from its twin at birth and exists beyond our field of view, scientists are left to wonder: why do we live in a matter-dominated universe?
In Search of Pure Dark Skies
Uploaded on Aug 13, 2011
Watch in 1080p! From ESOCast with the famous Dr. J. In the pursuit of pristine skies, the European Southern Observatory operates its telescopes in the remote and arid landscape of the Atacama Desert in Chile.
A top-class site for astronomical observations must meet several criteria. To begin with, of course, you need a sky that is free of clouds pretty much all year round. But in addition to that, you also need excellent atmospheric conditions, as well as very dry air with as little water vapor content as possible. And this is exactly the kind of environment that you find in the Atacama Desert in Chile.
The Chilean Coast Range. Here, the cold offshore Humboldt current creates a coastal inversion layer of cool air, which prevents rain clouds from developing. Often, a layer of fog is created, which rapidly disperses in the foothills above the desert. A view from the Paranal Observatory towards the Pacific Ocean clearly shows the top of the cloud layer.
Chilean coastal range Coastal clouds gathering at the foothills. In addition to the coastal inversion layer, a region of high pressure in the south-eastern Pacific Ocean creates circulating winds, forming an anticyclone, which helps to keep the climate of the Atacama dry.
The Andes lie to the east, acting as a natural barrier for clouds coming from this direction – so all the possible paths for moisture to reach the Atacama Desert are literally blocked. This results in extremely dry air and clear blue skies. Ideal conditions for astronomical observations.
But we’re not done yet with our checklist of ideal observing conditions. In addition to cloudless and dry skies, astronomers need dark sites and unpolluted air in order to make the best observations. In most places, the world at night is far from being a dark place and the light pollution caused by modern civilization can easily be spotted. However, light pollution hinders astronomical observations, as it brightens the night sky and makes faint celestial objects undetectable.
Only in places that are far from any cities – like some regions in the Atacama Desert – is the night sky pitch- black. Furthermore, because Chile’s cities are relatively far apart, the air in the Atacama Desert is almost completely free of pollutants and is extraordinarily transparent.
Now, astronomical observations are disturbed by the turbulent motions of pockets of air in the atmosphere. Essentially this turbulence blurs our images of the night sky. In addition, the atmosphere also absorbs and scatters light. In order to minimize these effects an observatory should be located in an area with a calm atmosphere above it and on top of a high mountain, in order to reduce the amount of atmosphere between your telescope and the stars. Once again, the high-altitude of Atacama Desert fits this description perfectly.
The Atacama Desert offers many sites at high altitude, ranging from extended plateau in the Altiplano highlands to high mountain tops close to the Pacific Coast. The Chajnantor plateau, at an altitude of 5000 meters, offers ideal conditions for observing in the millimeter and submillimeter wavelength domain. This is where ESO, together with its partners, has chosen to construct the Atacama Large Millimeter/submillimeter Array, or ALMA for short. At such high altitudes there is very little water vapor in the air and the disturbing effects of the atmosphere are kept to a minimum.
Cerro Paranal is an isolated mountain top in the Atacama Desert, only 12 kilometers inland from the Pacific Coast. This is the home of ESO’s Very Large Telescope, which makes good use of Cerro Paranal’s approximately 320 cloud-free nights each year.
Further inland, within sight of Paranal, another mountain has been identified as an ideal place to conduct astronomical observations: Cerro Armazones. This will be the future site of ESO’s Extremely Large Telescope, or the E-ELT, for short.
The Mars-like landscape of the Atacama Desert is really a wonderful gift of nature. Its unique climate makes it a first-class location for ESO’s powerful telescopes so that night after night ESO’s astronomers can observe the crystal clear skies.
Water Flows Discovered on Mars
Uploaded on Aug 4, 2011
Here is rotating globe of Mars and we’re going to zoom in on the middle Southern latitudes, the part of Mars where we find these active slope features, and we’re zooming in on the Newton Basin crater here.
What you can see are lots of gullies. The active features that we’ve recently discovered are on the slopes that are facing mostly to the North to the equator.
What we see are much smaller scale features than gullies. You can see_an area of bedrock, a steep cliff here, and it’s from that bedrock that these dark features flow out.
Given the latitude and the slope aspect and particular the temperatures, it suggests that there’s a volatile involved here and the appropriate volatile for this temperature is water, probably salty water because sometimes these are active when it’s a little bit below the freezing point of pure water, salt lowers the melting point. And water on Mars should be salty; we know there’s lots of salts on Mars.
This is potentially actual water, in the liquid state, flowing on Mars today not millions of years ago. In late spring and into the summer is when these features form and fade. By late summer – early fall they’ll be completely gone and we’ll see just a normal looking slope throughout the winter.
Every place where we have multiple years these features recurr.
They’re not exactly the same, they may be more or less active one year than another but they keep coming back.
Unexplained Gamma-Ray Pulsar
Uploaded on Jun 29, 2011
From NASA Astrophysics and Goddard Space Flight Center. In December 2010, a pair of mismatched stars in the southern constellation Crux whisked past each other at a distance closer than Venus orbits the sun. The system possesses a so-far unique blend of a hot and massive star with a compact fast-spinning pulsar. The pair’s closest encounters occur every 3.4 years and each is marked by a sharp increase in gamma rays, the most extreme form of light.
The unique combination of stars, the long wait between close approaches, and periods of intense gamma-ray emission make this system irresistible to astrophysicists. Now, a team using NASA’s Fermi Gamma-ray Space Telescope to observe the 2010 encounter reports that the system displayed fascinating and unanticipated activity.
Every 3.4 years, pulsar B1259-63 dives twice through the gas disk surrounding the massive blue star it orbits. With each pass, it produces gamma rays. During the most recent event, NASA’s Fermi observed that the pulsar’s gamma-ray flare was much more intense the second time it plunged through the disk. Astronomers don’t yet know why.
Few pairings in astronomy are as peculiar as high-mass binaries, where a hot blue-white star many times the sun’s mass and temperature is joined by a compact companion no bigger than Earth — and likely much smaller. Depending on the system, this companion may be a burned-out star known as a white dwarf, a city-sized remnant called a neutron star (also known as a pulsar) or, most exotically, a black hole.
Just four of these “odd couple” binaries were known to produce gamma rays, but in only one of them did astronomers know the nature of the compact object. That binary consists of a pulsar designated PSR B1259-63 and a 10th-magnitude Be-type star known as LS 2883. The pair lies 8,000 light-years away.
The pulsar is a fast-spinning neutron star with a strong magnetic field. This combination powers a lighthouse-like beam of energy, which astronomers can easily locate if the beam happens to sweep toward Earth. The beam from PSR B1259-63 was discovered in 1989 by the Parkes radio telescope in Australia. The neutron star is about the size of Washington, D.C., weighs about twice the sun’s mass, and spins almost 21 times a second.
The pulsar follows an eccentric and steeply inclined orbit around LS 2883, which weighs roughly 24 solar masses and spans about nine times its size. This hot blue star sits embedded in a disk of gas that flows out from its equatorial region.
At closest approach, the pulsar passes less than 63 million miles from its star — so close that it skirts the gas disk around the star’s middle. The pulsar punches through the disk on the inbound leg of its orbit. Then it swings around the star at closest approach and plunges through the disk again on the way out.
The Most Distant Quasar Ever Discovered
Uploaded on Jun 29, 2011
From ESO-Cast and the European Southern Observatory. Astronomers have discovered the most distant quasar found to date. This brilliant beacon, powered by a black hole with a mass two billion times that of the Sun, is by far the brightest object yet discovered in the early Universe.
Quasars are extremely bright, distant galaxies thought to be powered by supermassive black holes at their centers. These powerful beacons may help astronomers to probe the era when the first stars and galaxies were forming.
The quasar that has just been found is seen as it was only 770 million years after the Big Bang, at redshift 7.1. It took 12.9 billion years for its light to reach us.
Although more distant objects have been confirmed, such as a gamma-ray burst at redshift 8.2, and a galaxy at redshift 8.6, the newly discovered quasar is hundreds of times brighter than these. Among any other object bright enough to be studied in detail, this is the most distant by a large margin.
The next most-distant quasar is seen as it was 870 million years after the Big Bang (redshift 6.4). Similar objects further away cannot be found in visible-light surveys because their light, stretched by the expansion of the Universe, falls mostly in the infrared part of the spectrum by the time it gets to Earth. The European UKIRT Infrared Deep Sky Survey (UKIDSS) which uses the UK’s dedicated infrared telescope in Hawaii was designed to solve this problem. The team of astronomers hunted through millions of objects in this database to find those that could be the long-sought distant quasars, and eventually struck gold.
It took astronomers five years to find this quasar. Its distance was determined from observations made with ESO’s Very Large Telescope (VLT) and instruments on the Gemini North Telescope. Because the object is comparatively bright it is possible to take a spectrum of it (which involves splitting the light from the object into its component colors). This technique allowed the astronomers to find out quite a lot about the quasar.
These observations showed that the mass of the black hole at the center of the quasar is about two billion times that of the Sun. This very high mass is hard to explain so early on after the Big Bang. Current theories for the growth of supermassive black holes predict a slow build-up in mass as the compact object pulls in matter from its surroundings.
Pandora’s Dark Mystery
Uploaded on Jun 22, 2011
From the European Space Agency and the European Southern Observatory. This video explores recent observations of the galaxy cluster Abell 2744, nicknamed Pandora’s Cluster. Scientists have pieced together the cluster’s complex and violent history using telescopes in space and on the ground, including the Hubble Space Telescope and ESO’s Very Large Telescope. Abell 2744 seems to be the result of a simultaneous pile-up of at least four separate galaxy clusters, and this complex collision has produced strange effects that have never been seen together before.
When huge clusters of galaxies crash together, the resulting mess is a treasure trove of information for astronomers. By investigating one of the most complex and unusual colliding clusters in the sky, an international team of astronomers has pieced together the history of a cosmic crash that took place over a period of 350 million years.
Julian Merten, one of the lead scientists for this new study of cluster Abell 2744, explains: “Like a crash investigator piecing together the cause of an accident, we can use observations of these cosmic pile-ups to reconstruct events that happened over a period of hundreds of millions of years. This can reveal how structures form in the Universe, and how different types of matter interact with each other when they are smashed together.”
This cluster nicknamed Pandora’s Cluster because so many different and strange phenomena were unleashed by the collision. Abell 2744 has now been studied in more detail than ever before by combining data from the NASA/ESA Hubble Space Telescope, ESO’s Very Large Telescope (VLT), the Japanese Subaru telescope and NASA’s Chandra X-Ray Observatory.
The galaxies in the cluster are clearly visible in the Hubble and VLT images. Although the galaxies are bright they make up less than 5% of the mass there. The rest is gas (around 20%), which is so hot that it shines only in X-rays, and dark matter (around 75%), which is completely invisible. To understand what was going on in the collision the team needed to map the positions of all three types of matter in Abell 2744.
Dark matter is particularly elusive as it does not emit, absorb or reflect light (hence its name), but only makes itself apparent through its gravitational attraction. To pinpoint the location of this mysterious substance the team exploited a phenomenon known as gravitational lensing. This is the bending of light rays from distant galaxies as they pass through the gravitational field present in the cluster. The result is a series of telltale distortions in the images of galaxies in the background of the Hubble and VLT observations. By carefully plotting the way that these images are distorted, it is possible to map quite accurately where the mass — and hence the dark matter — actually lies.
By comparison, finding the hot gas in the cluster is simpler as NASA’s Chandra X-ray Observatory can observe it directly. These observations are not just crucial to find out where the gas is, but also to show the angles and speeds at which different components of the cluster came together.
When the astronomers looked at the results they found many curious features. “Abell 2744 seems to have formed from four different clusters involved in a series of collisions over a period of some 350 million years. The complicated and uneven distribution of the different types of matter is extremely unusual and fascinating,” says Dan Coe, the other lead author of the study.
It seems that the complex collision has separated out some of the hot gas and dark matter so that they now lie apart from each other, and from the visible galaxies. Pandora’s Cluster combines several phenomena that have only ever been seen singly in other systems.
Near the core of the cluster is a “bullet”, where the gas of one cluster collided with that of another to create a shock wave. The dark matter passed through the collision unaffected .
In another part of the cluster there seem to be galaxies and dark matter, but no hot gas. The gas may have been stripped away during the collision, leaving behind no more than a faint trail.
Even odder features lie in the outer parts of the cluster. One region contains lots of dark matter, but no luminous galaxies or hot gas. A separate ghostly clump of gas has been ejected, which precedes rather than follows the associated dark matter. This puzzling arrangement may be telling astronomers something about how dark matter behaves and how the various ingredients of the Universe interact with each other.
Galaxy clusters are the biggest structures in the cosmos, containing literally trillions of stars. The way they form and develop through repeated collisions has profound implications for our understanding of the Universe. Further studies of the Pandora’s Cluster, the most complex and fascinating merger yet found, are in progress.
Warped Galaxy in Turmoil
Uploaded on Jun 15, 2011
From HubbleCast and Dr. J. The Hubble Space Telescope has produced a close-up view of the galaxy Centaurus A. Hubble’s multi-wavelength image is the most detailed ever made of this dynamic and dusty galaxy.
Centaurus A is well known for its huge dust lanes that stretch across the entire extent of the galaxy. Hubble’s new observations are an extreme close-up of a small part of these dust lanes. This new image is made from observations in ultraviolet, optical and near- infrared light. The utraviolet light shows us the location of hot young stars, whereas the near infrared light allows us to glimpse some of the details that are obscured by dust in the optical.
Astronomers think that Centaurus A must have collided and merged with another galaxy at some point in the past. The shockwaves of this event caused hydrogen gas to coalesce and sparked intense areas of star formation, as seen in the red patches visible here. The turmoil of this collision also explains the warped shape of the galaxy’s disc.
Looking at a broader view taken by ESO’s Wide Field Imager reveals the extent of the distortion in Cen A’s shape, as well as further areas of vigorous star formation.
The galaxy contains a highly active supermassive black hole at its center. Powerful relativistic jets release vast amounts of radio and X-ray radiation. Although Hubble can’t see this, submillimeter telescopes like APEX can see broad plumes of matter being ejected far out from the galaxy.
At just over 11 million light-years distant, Cen A is relatively close in astronomical terms. In fact, it’s not only close, it is very bright. Amateur astronomers with a view of the southern skies can see it with just a pair of binoculars, while those with a largish amateur telescope can even make out the dust lanes.
But only Hubble reveals this much detail. Not only does the space telescope offer unprecedented clarity due to its position above the distorting effects of the atmosphere: it is also able to observe ultraviolet and infrared wavelengths with pristine clarity.
Strange Magnetic Bubbles at the Edge of the Solar System
Uploaded on Jun 9, 2011
A gem from NASA Heliophysics and the Science Visualization Studio. The sun’s magnetic field spins opposite directions on the north and south poles. These oppositely pointing magnetic fields are separated by a layer of current called the heliospheric current sheet. Due to the tilt of the magnetic axis in relation to the axis of rotation of the Sun, the heliospheric current sheet flaps like a flag in the wind. The flapping current sheet separates regions of oppositely pointing magnetic field, called sectors. As the solar wind speed decreases past the termination shock, the sectors squeeze together, bringing regions of opposite magnetic field closer to each other. The Voyager spacecraft have now found that when the separation of sectors becomes very small, the sectored magnetic field breaks up into a sea of nested “magnetic bubbles” in a phenomenon called magnetic reconnection. The region of nested bubbles is carried by the solar wind to the north and south filling out the entire front region of the heliopause and the sector region in the heliosheath.
This discovery has prompted a complete revision of what the heliosheath region looks like. The smooth, streamlined look is gone, replaced with a bubbly, frothy outer layer.
Catching Solar Waves
Uploaded on Jun 7, 2011
From NASA Goddard Space Flight Center. Scientists have spotted the iconic surfer’s wave rolling through the atmosphere of the sun. This makes for more than just a nice photo-op: the waves hold clues as to how energy moves through that atmosphere, known as the corona.
Since scientists know how these kinds of waves — initiated by a Kelvin-Helmholtz instability if you’re being technical — disperse energy in the water, they can use this information to better understand the corona. This in turn, may help solve an enduring mystery of why the corona is thousands of times hotter than originally expected.
Kelvin-Helmholtz instabilities occur when two fluids of different densities or different speeds flow by each other. In the case of ocean waves, that’s the dense water and the lighter air. As they flow past each other, slight ripples can be quickly amplified into the giant waves loved by surfers. In the case of the solar atmosphere, which is made of a very hot and electrically charged gas called plasma, the two flows come from an expanse of plasma erupting off the sun’s surface as it passes by plasma that is not erupting. The difference in flow speeds and densities across this boundary sparks the instability that builds into the waves.
In order to confirm this description, the team developed a computer model to see what takes place in the region. Their model showed that these conditions could indeed lead to giant surfing waves rolling through the corona. Seeing the big waves suggests they can cascade down to smaller forms of turbulence too. Scientists believe that the friction created by turbulence — the simple rolling of material over and around itself — could help add heating energy to the corona. The analogy is the way froth at the top of a surfing wave provides friction that will heat up the wave.
Cosmic Journeys : What an Astronaut’s Camera Sees (from ISS)
Uploaded on May 26, 2011
An intimate tour of Earth’s most impressive landscapes… as captured by astronauts with their digital cameras. Dr. Justin Wilkinson from NASA’s astronaut team describes the special places that spacemen focus on whenever they get a moment.
We start with the coast of Namibia in southwestern Africa, the very dry desert coast of the Namib Desert. You can see a cloud band butting up against the shore and some straight sand dunes in the lower left of the picture. Yeah those are big red sand dunes that the astronauts say is one of the most beautiful sites that you can get when you’re flying.
Coming into the view on the left is an impact crater right in the middle of the picture, right about now and some wind streaks. We know where this area is because it’s a bit unique. We’ve got a major dune field coming into the picture on the left there: the Oriental Sand Sea, as it’s called in French, and on the top is the Isawan Sand Sea.
This is the island of Sicily with cloud over Mt. Etna, so you can’t quite tell there’s a big volcano in the middle of the picture right now. And there’s the toe of the boot of Italy coming into the picture from the left. See a good example of sun glint on the right with the sea reflecting the sun.
This is the smooth east coast of the Kamchatka peninsula again. As you move inland it gets even more striking as a picture because of all the volcanoes on this peninsula and the snowy mountains. There’s a volcano just coming into the picture from the top left there. You can see a knob-shaped feature.
Here is a smaller finger of land in China sticking into the Pacific Ocean. In winter you can see all the snow lower left. This is called the Qindoa P eninsula and we recognize it. And again, the sun glint point moving along the coast upper center.
In a very clear picture, the Zagros mountains with snow on them in Iran, in the country of Iran.
Here we have the north coast of Australia and the gulf of Carpenteria and some islands. The biggest island at the bottom of the screen there is Groote island, which means the big island in Dutch.
When you see a huge powerful feature like this and the astronauts do shoot them a lot and we have had some detailed views looking right down the eye, looking at the eyewall. In fact I seem to remember views of breaking waves on the sea surface at the bottom of the eye. Amazing detail.
Look at this neat picture of Great Salt Lake in Utah. And the variation in color? That’s due to an almost a complete blockage of the circulation of the lake by a trestle for a railroad that crosses from one side to the other. It stops the circulation and things get a little bit saltier and certainly saltier at the north end of the lake.
Here you see two circles coming in to the top of the view now. These are either volcanoes or effects from inside the earth producing circular features. We think this is the Big Bend area of Texas.
This is an interesting sideways view of the peninsula of Florida, with the Keys stretching out into the lowest part of the picture there. And the shallow seas around the Bahama Islands top right. And Cuba coming into the picture lower right.
And this I believe is the coast of Northern Chile in South America. It’s a very straight coast, except for that strange headland out to the right just disappearing. And so the desert is the first part of the inland zone, and then you see much blacker at the top of the picture the Andes Mountains with some many dozens of volcanoes.
Here is a thunderhead. The typical look of the thunderheads, the big rainstorms, that develop over the Amazon Basin. And another one coming in top right. Here’s an obviously a major river. There’s an even bigger one coming in on the right. That looks to me like it could well be the Amazon River, with one of its big tributaries on the left. And the flow would seem to be from the bottom of the picture to the top.
Voyager Humanity’s Farthest Journey
Uploaded on May 2, 2011
From NASA JPL marking the passage of the twin Voyager spacecraft beyond our solar system. We knew we were on a journey of discovery when we launched the Voyager spacecraft, but we had no idea how much there was to discover.
We had a sense that we knew what it felt like to be Magellan or Columbus.
Time after time we were surprised by seeing things that we had not expected or even imagined. From volcanoes erupting from the moon Io to the possibility of a liquid water ocean under the icy crust of Europa. Titan, where we found an atmosphere. Uranus’ small moon Miranda, which had one of the most complex geologic surfaces we’d seen. Even at Neptune, Triton, 40 degrees above absolute zero, even there there were geysers erupting.
It’s the only spacecraft that’s gone by Uranus. It’s the only spacecraft that’s gone by Neptune. Everything we know about those planets we know from Voyager.
To see those first pictures coming in from the outer solar system, for the first time what had been a point of light in the sky was a place.
I really credit the people that designed the mission, both the engineers and the mission planners and scientists because not only did they build an extremely robust, durable spacecraft, but they had the vision to send it on a path such that it could get out into interstellar space and carry a gold record.
And here was this Noah’s Ark of human culture that was being sent to the outer planets and then beyond to wander in the interstellar darkness for a billion years. On Valentine’s Day 1990 Voyager 1 looked homeward. And what did it find? Not the frame-filling Apollo Earth, but, instead, that one-pixel Earth. That’s here. That’s home.
The Voyager spacecraft are in the outer layer of the heliosphere, the giant bubble the sun creates around itself with its supersonic wind. Voyager today is headed for the edge of interstellar space. That’s the space between stars, and it’s filled with material that has been injected by the explosion of stars,matter which came from a particular direction, creating a wind,which has shaped the bubble in which the solar system is surrounded.
Voyager really has changed our view of the solar system. This will be a milestone in space exploration: leaving the solar system,leaving the bubble and entering interstellar space for the first time.
Cosmic Journeys : Mars: World That Never Was
Uploaded on Apr 30, 2011
Did Mars long ago develop far enough for life to arise? If so, does anything still live within Mars’ dusty plains, beneath its ice caps, or somewhere underground?
In 1964 the Mariner Four spacecraft flew by Mars and got a good look. What it saw looked more like the Moon than the Earth. Then, in the mid-1970’s, two lander-orbiter robot teams, named Viking, went in for an even closer look. The landers tested the soil for the chemical residues of life. All the evidence from Viking told us: Mars is dead. And extremely harsh.
The mission recorded Martian surface temperatures from -17 degrees Celsius down to -107. We now know it can get even colder than that at the poles. The atmosphere is 95% carbon dioxide, with only traces of oxygen. And it’s extremely thin, with less than one percent the surface pressure of Earth’s atmosphere.
And it’s bone dry. In fact, the Sahara Desert is a rainforest compared to Mars, where water vapor is a trace gas in the atmosphere. On Earth, impact craters erode over time from wind and water… and even volcanic activity. On Mars, they can linger for billions of years.
Earth’s surface is shaped and reshaped by the horizontal movement of plates that make up its crust driven by heat welling up from the planet’s hot interior. At half the width and only 11% the mass of Earth, Mars doesn’t generate enough heat to support wide-scale plate tectonics.
Nor does it have the gravity to hold a thick atmosphere needed to store enough heat at the surface to allow liquid water to flow. Nonetheless, some areas that looked to Viking-era scientists like craters and volcanic areas, were later shown to be riverbeds, lake bottoms, and ocean shorelines.
If water once flowed on Mars’ surface, where did it all go?
This was the scene at NASA’s Jet Propulsion Lab in 2004. The twin rovers Spirit and Opportunity had just bounced down on the Red Planet. When the excitement died down, the rovers were set off on one of the most remarkable journeys in the history of planetary exploration. Missions like this could one day pave the way for a day when we’ll view images from a real astronaut’s camera.
Opportunity had come to rest in a small crater near the equator, at a spot called Meridiani Planum. Here, in plain view, on a nearby crater wall, its camera revealed exposed bedrock, the first ever seen on Mars. Not far away, the rover found layered rocks on the face of a cliff. On Earth, they typically form as sedimentary layers at the bottom of oceans.
And at every turn, Opportunity rolled across tiny, smooth, round pellets. They became known as “blueberries” because they appeared purplish-brown against Mars’ rust-colored surface. Initially thought to be volcanic in origin, they turned out to be iron-rich spherules of the type that form within cavities in the mud at the bottom of an ocean.
Drilling into rocks, the rover inserted a spectrometer to read the mineral content. The readings showed significant amounts of sulfate salt, a tracer for standing water. That wasn’t all. Spirit’s broken wheel, dragging behind it, exposed soils saturated in salt.
Clearly there once was water on Mars’ surface, but how long ago? And, if there is anything left, where would you find it? One possible answer: the North Pole. From orbit, this region seemed to be covered in frozen CO2 – what we call dry ice. But was there water ice below the surface?
Enter Phoenix, a lander that touched down near the North Pole in early 2008. Radar readings from orbit, taken by the Mars Express mission, hinted at the presence of ice just below the surface.
The Phoenix lander’s descent thrusters blew away the top layer of soil, allowing its camera to snap pictures of what looked like ice. Scientists instructed the robot to conduct a simple experiment: reach out and dig a trench, then watch what happens.
As expected, clumps of white stuff appeared. A couple of days later, it was gone. Vaporized. That means it can’t be salt or frozen CO2, which is stable in the cold dry temperatures of the Martian pole. So it had to be water, the first ever directly seen on Mars.
There are indications that the North Pole was actually warm enough in the recent past for water ice to become liquid. The Mars Reconaissance Orbiter, or MRO, used radar pulses to peer beneath the surface of the ice cap. These data reveal that the ice, just over a mile thick, formed in a succession of layers as the climate alternated between warm and cold.
Our planet avoids mood swings like this in part because its spin is stabilized by a massive moon. Mars’ spin is not, so it can really wobble, with the pole tilting toward the sun for long periods. New observations by the MRO spacecraft show that these wobbles can lead to dramatic releases of CO2, and warming periods due to an increase in the greenhouse effect.
Cosmic Journeys : Saturn’s Mysterious Moons
Uploaded on Apr 14, 2011
Launched three years before the new century… a spacecraft wound its way through the empty reaches of the solar system. On Earth, its progress was little noted, as it swung twice by the planet Venus, then our moon. And Earth. The asteroid belt. And Jupiter.
Almost seven years later, on the first of July 2004, the Cassini probe entered the orbit of Saturn. It then began to compile what has become one of the greatest photographic collections of all time, of a giant gas planet, surrounded by colorful rings, guarded by a diverse collection of moons, and millions of tiny moonlets.
Within this record, is a trail of clues… pointing to the energy sources and complex chemistry needed to spawn life. What are these mysterious worlds telling us about the universe, and Earth?
In the outer reaches of the solar system, a billion and a half kilometers from the Sun… there is a little world known as Enceladus. Nearly all of the sunlight that strikes its icy surface is reflected back into space, making it one of the brightest objects in the solar system.
At its equator, the average temperature is minus 198 degrees Celsius. It can rise about 70 degrees higher in grooves that stretch across the south pole like tiger stripes. Looming over it is the giant planet Saturn.
In myth, Saturn – the Roman name for the primal Greek God Chronos – was the youngest son of Gaia, or Earth, and Uranus, sky. Wielding a scythe provided by his mother, the story goes, Saturn confronted his abusive father, castrating him. The blood of Uranus flowed into the seas, fertilizing the Earth and giving rise to Enceladus and other giant offspring.
Saturn’s moon Enceladus has its own tangled story. In 2005, the Cassini spacecraft spotted plumes of water vapor shooting out into space from its south pole.
More recent close encounters have revealed jets of water, flavored by slightly salty chemical compounds, spewing out from vents in the rough, cracked polar terrain. That may mean that Enceladus harbors a remarkable secret below its frigid surface: A liquid ocean, and perhaps, a chemical environment that could spawn simple life forms.
It’s not the only promising stop in the realm of Saturn. The moon Titan is often said to resemble Earth in its early days. It is lined with volcanoes and a hazy atmosphere rich in organic compounds.
While Enceladus is the size of Great Britain, Titan is ten times larger, 50% larger than our moon, and the second largest moon in our solar system.
We’ve known about Titan since the astronomer Christian Huygens discovered it in 1655, and Enceladus since William Herschel spotted it in August 1789, just after the start of the French Revolution.
Scientists began to investigate these moons in earnest with the launch of the two Voyager spacecraft in 1977. The lineup of outer planets in the solar system allowed the spacecraft to fly past each of them.
They disclosed new details about their magnetic fields, atmospheres, ring systems, and inner cores. But what really turned heads were the varied shapes and surfaces of their moons.
They’ve all been pummeled over the millennia by wayward asteroids and comets. A few appear to be sculpted by forces below their surfaces. Neptune’s largest moon Triton has few craters. It’s marked with circular depressions bounded by rugged ridges. There are also grooves and folds that stretch for dozens of miles, a sign of fracturing and deforming.
Triton has geysers too, shooting some five miles above the surface. But on this frigid moon — so far from the Sun — the liquid that spouts is not water but nitrogen.
Tiny Miranda, one of 27 known moons that orbit Uranus, wears a jumbled skin that’s been shaped and reshaped by forces within. Jupiter’s moon Io — orbiting perilously close to the giant planet is literally turning itself inside out. Rivers of lava roll down from open craters that erupt like fountains.
Flying by Europa, Voyager documented a complex network of criss-crossing grooves and ridges. In the 1990s, the Galileo spacecraft went back to get a closer look. It found that Europa’s surface is a crazy quilt of fractured plates, cliff faces and gullies… amid long grooves like a network of superhighways. How did it get like this?
Then, heat rising up through a subsurface ocean of liquid water cracks, and shifts, and spreads the icy surface in a thousand different ways. Europa’s neighbors, Callisto and Ganymede, show similar features, suggesting they too may have liquid oceans below their surfaces.
Crossing outward to Saturn, Voyager found a similar surface on the moon Enceladus. So when the Cassini spacecraft arrived in 2004, it came looking for answers to a range of burning questions: if this moon and others have subsurface oceans? Do they also have the ability to cook up and support life? And what could they tell us about the origin of life throughout the galaxy?
Neutron Star Collision and Gamma Ray Burst Discovery
Uploaded on Apr 7, 2011
From NASA Astrophysics and Goddard Space Flight Center. Every day or two, on average, satellites detect a massive explosion somewhere in the sky. These are gamma-ray bursts, the brightest blasts in the universe. They’re thought to be caused by jets of matter moving near the speed of light associated with the births of black holes. Gamma-ray bursts that last longer than two seconds are the most common and are thought to result from the death of a massive star. Shorter bursts proved much more elusive.
In fact, even some of their basic properties were unknown until NASA’s Swift satellite began work in 2004. A neutron star is what remains when a star several times the mass of the sun collapses and explodes. With more than the sun’s mass packed in a sphere less than 18 miles across, these objects are incredibly dense. Just a sugar-cube-size piece of neutron star can weigh as much as all the water in the Great Lakes.
When two orbiting neutron stars collide, they merge and form a black hole, releasing enormous amounts of energy in the process. Armed with state-of-the-art supercomputer models, scientists have shown that colliding neutron stars can produce the energetic jet required for a gamma-ray burst. Earlier simulations demonstrated that mergers could make black holes. Others had shown that the high-speed particle jets needed to make a gamma-ray burst would continue if placed in the swirling wreckage of a recent merger.
Now, the simulations reveal the middle step of the process –how the merging stars’ magnetic field organizes itself into outwardly directed components capable of forming a jet. The Damiana supercomputer at Germany’s Max Planck Institute for Gravitational Physics needed six weeks to reveal the details of a process that unfolds in just 35 thousandths of a second. The new simulation shows two neutron stars merging to form a black hole surrounded by super-hot plasma.
On the left is a map of the density of the stars as they scramble their matter into a dense, hot cloud of swirling debris. On the right is a map of the magnetic fields, with blue representing magnetic strength a billion times greater than the sun’s. The simulation shows the same disorderly behavior of the matter and magnetic fields. Both structures gradually become more organized, but what’s important here is the white magnetic field. Amidst this incredible turmoil, the white field has taken on the character of a jet, although no matter is flowing through it when the simulation ends.
Showing that magnetic fields suddenly become organized as jets provides scientists with the missing link. It confirms that merging neutron stars can indeed produce short gamma-ray bursts. At this moment, somewhere across the cosmos, it’s about to happen again.
Into the Spider’s Lair
Uploaded on Mar 24, 2011
From Hubblecast, the famed Tarantula Nebula explored in a detailed new image from the Hubble Space Telescope. The Large Magellanic Cloud, or LMC, is a small companion galaxy of our own Milky Way. It can be seen with the naked eye, as a faint grey blotch in the constellation of Dorado.
It’s a favorite hunting ground for astronomers and it has been studied by many telescopes. Its most dramatic feature is the Tarantula Nebula, a bright region of glowing gas and energetic star formation. Hubble has produced a close-up view of this nebula, which reveals this dynamic region of our Universe in unprecedented detail.
This part of the Tarantula Nebula is one of its most dynamic, showing the area around the supernova remnant NGC 2060. These wispy tendrils of dust and gas are the only visible remnant of a star which has exploded.
After puffing out these smoky remains, the core of the star that formed NGC 2060 collapsed into a pulsar, which is a type of neutron star. The Tarantula nebula glows brightly because the atoms in its hydrogen gas are excited by the bright, newborn stars that have recently formed here.
These toddler-stars shine forth with intense ultraviolet radiation that ionizes the gas, making it light up red and green. The light is so intense that although around 170 000 light-years distant, and outside the Milky Way, the Tarantula Nebula is nevertheless visible without a telescope on a dark night to Earth-bound observers.
But the biggest and brightest stars in the Tarantula are actually just outside Hubble’s field of view. This wider, but less detailed view of the Tarantula Nebula was taken with the MPG/ESO 2.2-metre telescope, at La Silla Observatory in Chile. It shows the source of much of the Tarantula’s light: the super star cluster RMC 136.
So it wasn’t in fact that long ago that astronomers were still debating whether this intense light came from a compact star cluster, or perhaps an unknown kind of super-star. It’s only been in the past 20 years that we have been able to prove that it is indeed a star cluster – albeit one that hosts some of the most massive stars that have ever been observed.
The Tarantula Nebula also hosts the supernova 1987a. Now, of all the supernovae that have been observed since the invention of the telescope, this one is by far the closest to us. Pulling further back, the size of the Tarantula Nebula relative to its host galaxy becomes clear. It is the brightest known star forming region in the local Universe and one of the most attractive spots in the night sky.
Cosmic Journeys : Attack of the Sun
Uploaded on Mar 18, 2011
Massive solar eruptions take aim at our high-tech society. 93 million miles away… an angry sun vents its rage. Dark regions, called sunspots, appeared unexpectedly on its surface… a sign of rising tension within. It had been three and a half years since the sun last erupted in fury…at the peak of an 11-year cycle of solar flare-ups.
Back then, we got ready for it… by shutting down satellites that were vulnerable to high levels of radiation. But no one expected this. In what should have been a low point in solar activity, the sun erupted in a series of massive explosions, called coronal mass ejections, or CMEs.
Electrified gas clouds weighing billions of tons raced outward. Solar telescopes recorded the action… The largest emission of solar x-rays ever seen. The hottest flares, at tens of millions of degrees. And the fastest… reaching speeds clocked at six million miles per hour.
The sun became a giant plasma weapon… more potent than any in science fiction… and pointed right at our home planet. On Earth… the Halloween storms produced some of the most spectacular auroras ever seen at the north and south poles. They also brought jolts of electricity that caused power outages in Sweden, and disrupted airline navigation.
In space, these storms damaged 28 communications satellites, and destroyed two. And they didn’t stop there. As the energetic surge swept past Mars, it was so strong it burned out the radiation monitor aboard the spacecraft, Mars Global Surveyor. Ironically, this instrument was designed to study radiation that human explorers might encounter on future missions beyond Earth.
Months later, the rush of solar energy washed over the two Voyager spacecraft, on their way to the far reaches of the solar system. CMEs like these have been known to blast their way out the far edges of the solar system, where the solar wind meets the flow of gas around the galaxy itself.
This stormy season on the sun lasted about five weeks. It was by no means the worst. A solar eruption in 1859 was so powerful it set fire to telegraph offices… several people got nasty electric shocks, simply because they were working with metal objects… and for the next few nights, auroras were reportedly bright enough to read by.
A similar storm today could easily cause more than two trillion dollars in damage to our high-tech infrastructure, twenty times greater than hurricane Katrina. But believe it or not, the threat is about to get even worse. We are beginning to change the way we acquire and use energy… by expanding our power grid to accommodate wind farms…solar arrays… new nuclear plants … and other renewable energy sources.
This grid will get larger… and smarter…. With microprocessors in most every device…communicating and negotiating with one another… running everything from air conditioners to power plants. A sudden surge of solar activity could strike the grid directly…inflicting a substantial amount of damage on the emerging smart power economy.
To understand what a powerful force the sun can be. Take a look at Venus. At almost exactly the same size and mass as Earth, it’s truly our sister planet. The thinking is that long ago, fierce solar winds stripped off lighter water molecules from its upper atmosphere. What was left was a witches’ brew of acidic gases and carbon dioxide that thickened at lower altitudes, rising to some 90 times the density of Earth’s atmosphere.
At a concentration of 95% in Venus’ atmosphere, CO2 gas trapped increasing amounts of sunlight and drove surface temperatures close to 1000 degrees Fahrenheit. How did Earth avoid such a harsh fate?
One of the main reasons is that our planet has what Venus lacks… a natural defense against solar attacks.
Heartbeat of a Black Hole
Uploaded on Mar 2, 2011
This video is based on recent findings made by astronomers using the Chandra X-Ray Observatory and the Rossi X-Ray Timing Explorer of a pulsing “heartbeat” coming from the binary star-black hole system GRS-1915.
The link made to the famous Yeats poem “The Second Coming” does not reference the complex religious and historical imagery of this famous poem. Rather, it’s designed to evoke the violent rise of a cosmic monster, a black hole.
Here’s a brief analysis of the Yeats poem:http://www.yeatsvision.com/SecondNote…
All around the universe, energy roars out of cauldrons of matter… in the form of winds… jets… shock waves. While gravity… pulling matter in, smashes and pulverizes it.
In the crucible of this epic conflict… our universe builds majestic galaxies…. stars that can shine for trillions of years… and planets that may well produce life. There are times, though, when these forces lock, and… “the ceremony of innocence is drowned.”
In the plane of our galaxy, GRS 1915 is a star with a black hole bound together by gravity. This 14 solar mass black hole is steadily drawing mass from its companion.
Two space telescopes…. the Chandra X-Ray Observatory and the Rossi X-ray Timing Explorer… recorded pulses of x-ray light… one every 50 seconds. What’s causing this strange heartbeat?
Matter swirling into the black hole forms a disk that pushes in close to the black hole’s event horizon. Gas, racing around the monster this close is thought to approach 50% the speed of light.
Heat and magnetic energy build to a critical level. “The center cannot hold.” The disk erupts… blasting some inflowing matter back into space… at a rate some 25 times greater than what the black hole can swallow. This will go on until the star is stripped bare.
“The darkness drops again.”
“And what rough beast, its hour come round at last…”
Hubble Black Hole Probe
Uploaded on Mar 1, 2011
From HubbleCast. For centuries, scientists imagined objects so heavy and dense that their gravity might be strong enough to pull anything in, including light. They would be, quite literally, a black hole in space. But it’s only in the past few decades that astronomers have conclusively proved their existence. Today, Hubble lets scientists measure the effects of black holes, make images of their surroundings and glean fascinating insights into the evolution of our cosmos.
In science fiction, black holes are often portrayed as some kind of menacing threat to the safety of the whole Universe, like giant vacuum cleaners that somehow suck up all of existence. Now, in this episode, we’re going to separate the fiction from the facts and we’re going to look at the real science behind black holes and how Hubble has contributed to it.
Black holes come in different sizes. We’ve had solid evidence for the smaller ones since the 1970s. These form when a huge star explodes at the end of its life. As the outer layers are blown away, the star’s core collapses in on itself forming an incredibly dense ball. For instance, a black hole with the same mass as the Sun would have a radius of only a few kilometers.
Before Hubble was launched, astronomers had noticed that the centers of many galaxies were somehow much denser and brighter than they were expected to be. And so they speculated that there must be some kind of huge, massive objects lurking in the centers of these galaxies in order to provide the additional gravitational attraction.
Now, could these objects be supermassive black holes, that is, black holes which are millions or even billions of times more massive than the stellar ones? Or was there perhaps a simpler, less exotic explanation, like giant star clusters?
Fortunately, Hubble was on its way, along with a range of other high-tech telescopes. When the space telescope was being planned, the search for supermassive black holes was in fact one of its main objectives.
Some of Hubble’s early observations in the 1990s were dedicated to these dense, bright galactic centers. Where ground-based telescopes were just seeing a sea of stars, Hubble was able to resolve the details.
In fact, around the very centers of these galaxies, Hubble discovered rotating discs of gas and dust.
When Hubble observed the disc at the center of a nearby galaxy, Messier 87, the astronomers saw that its color was not quite the same on both sides. One side was shifted towards blue and the other towards red, and this told the scientists that it must have been rotating very quickly.
This is because the wavelength of light is changed by the motion of an object emitting it. Think about how the pitch of an ambulance siren drops as it drives past you, because the sound waves are more spaced out as the vehicle moves away.
Similarly, if an object is moving towards you, the light’s wavelength is squashed, making it bluer; if it’s moving away, it’s stretched, making it redder. This is also known as the Doppler effect.
So, by measuring how much the colours had shifted on either side of the disk, astronomers were able to determine its speed of rotation. And it turned out that this disk was spinning at a rate of hundreds of kilometers per second. This in turn allowed astronomers to deduce that, hidden at the very center, there must be some kind of object which was two to three billion times the mass of the Sun – and this was very likely a supermassive black hole.
Now, along with a lot of other observations, this was a key piece of evidence that led to the notion that there is a supermassive black hole lurking at the center of most, if not all, giant galaxies, including our own Milky Way.
Well, the science of black holes has moved along a lot since then. The mystery now isn’t whether they exist, but why they behave in the strange ways they do.
For example, Hubble observations have helped to show that the mass of a supermassive black hole is closely related to the mass of its surrounding host galaxy. The bigger the black hole, the bigger the galaxy.
A supermassive black hole is pretty big, and it packs a lot of punch, but you’ve got to remember that compared to its host galaxy it’s actually tiny. The region of space that is most obviously and most immediately influenced by a supermassive black hole is in fact about a million times smaller than its surrounding galaxy. That’s about the same size difference as between this coin and a whole city. So it’s pretty hard to think of any processes that would link the two in a long-lasting way.
So a big area in science just now is trying to find out what’s going on here, and why the two are linked. Do black holes regulate the size of galaxies, or do galaxies regulate the size of black holes? Or is something altogether different happening?
Cosmic Journeys : Alien Planets & Eyeball Earths: The Search for Habitable Planets
Uploaded on Feb 27, 2011
Find out where to look for Extraterrestrial Life. What planets are likely to have the right conditions? And what makes Earth special? So far, in this age of planet hunting, we’ve yet to find anything like our solar system… with rocky inner planets in neat circular orbits, and evenly spaced gas giants on the periphery.
Instead, astronomers have glimpsed a diverse planetary zoo, with giant planets in wide orbits around their parent stars, others that swing in so close they leave a comet-like tail, or molten rocky worlds emblazoned with oceans of lava. These finds have added new complexity to theories of how solar systems emerge in the birth of a star.
As dust and gas swirl into the newborn star, they form a proto-planetary disk. Within this Frisbee-like structure, gravity sculpts planetary bodies that grow in size, sweeping up smaller bodies that form around them. Current theory holds that giant planets, forming on the periphery, commonly migrate into the inner solar system. This confirms the observation of so-called hot Jupiters orbiting perilously close to their parent stars.
But these giants may clear out smaller rocky planets that form close to the star, creating a planetary desert… just where you’d hope to find life. Does that make the search for another Earth a wild goose chase? To find out, a group of planet hunters, using the Keck Telescope in Hawaii, examined a sample of 166 sun-like stars within 80 light years of Earth.
To their surprise, they found that as many as a quarter of all sun-like stars should have planets roughly the size of Earth. Now enter the Kepler Space Telescope, launched in March 2009 on a mission to find Earth-like planets.
Over a four-month period in 2009, it observed the light of over 150,000 stars, within 3000 light years of Earth. The data showed that at least in one case, the planetary desert is not so barren.
The star Kepler 11 is a yellow dwarf similar to our sun. It has at least five planets close enough to be inside the orbit of our Mercury, with a sixth inside the orbit of Venus. There may well be additional planets further out. That won’t be known until 2012, when data from longer orbits is complete.
Overall, Kepler turned up 58 planets in the so-called habitable zone. Most are large gas planets, but who’s to say that some of them don’t have moons with liquid water? Think Avatar, Pandora.
With a growing planetary database, astronomers are beginning to redefine what it takes to spawn life as we know it. Ideally, astronomers will one day stumble upon a world about the size of Earth, with oceans, an atmosphere, a moon to stabilize its orbit, a robust magnetic field to shelter it from solar winds, and creatures beaming television shows into space that reveal their presence.
Until then, the most fertile ground for finding life turns out to be a long-overlooked class of stars.
M Stars, or red dwarfs, range from one half to one-twentieth the mass of our sun and make up 76% of all the stars in our galaxy. The most famous is in the southern constellation of Libra, just 20 light years away, called Gliese 581. A team of French and Swiss astronomers had been studying its light from a telescope in the mountains of Chile.
They noticed a slight jitter: the gravitational tugging of planets. From this so-called radial velocity, they deduced the presence of Gliese 581B, a planet with sixteen times the mass of Earth. At a distance of only six million kilometers, it’s bound to be very hot.
Then came planet C, with an orbit of 11 million kilometers. Still too hot. Then there’s D, at about 33 million kilometers from its sun.
At the outer edge of the star’s habitable zone, it receives only 30% of the light that Earth gets from our Sun. Compare it to Mars, where surface temperatures average around –59 degrees Celsius Astronomers suspect that Planet D is an icy world that migrated in from the outer solar system.
Red dwarfs are known as “Flare Stars” for the violent eruptions that take place on their surfaces. In 1985, the red dwarf AD Leo erupted with a thousand times more power than the worst solar eruptions. To find out what that would do to a planet in a close orbit, scientists simulated the blast.
They found that ultraviolet radiation from the star would split oxygen molecules in the planet’s atmosphere, forming ozone. That’s could be enough to shield it from harm. Studies like this are prompting scientists to redefine just what they mean by “habitable zone.”
360 view of the Full Sun
Uploaded on Feb 6, 2011
From NASA Heliophysics. Seeing the whole sun front and back simultaneously will enable significant advances in space weather forecasting for Earth, and improve planning for future robotic or crewed spacecraft missions throughout the solar system.
These views are the result of observations by NASA’s two Solar TErrestrial Relations Observatory (STEREO) spacecraft. The duo are on diametrically opposite sides of the sun, 180 degrees apart. One is ahead of Earth in its orbit, the other trailing behind.
Launched in October 2006, STEREO traces the flow of energy and matter from the sun to Earth. It also provides unique and revolutionary views of the sun-Earth system. The mission observed the sun in 3-D for the first time in 2007. In 2009, the twin spacecraft revealed the 3-D structure of coronal mass ejections which are violent eruptions of matter from the sun that can disrupt communications, navigation, satellites and power grids on Earth.
Planet Vulcan: Toxic Oasis
Uploaded on Jan 28, 2011
Check out this animation from the Kepler space telescope portraying a dramatic planetary discovery. Kepler-10b, it’s called, orbits its sun at a distance more than 20 times closer than Mercury is to our Sun. The daytime temperature is more than 2,500 degrees Fahrenheit. Intense radiation from the star has stripped it of any atmosphere.
Instead, the planet’s molten surface throws off a strange kind of haze… flecks of silicates and iron swept away by stellar radiation, much like a comet’s tail when its orbit brings it close to the Sun.
Call this hot world Vulcan… after the Roman god of fire. We can only imagine what it’s like down on the surface. The gravitational twisting and tugging from the parent star have likely endowed its rocky surface with lakes and rivers of lava.
It’s not a place for us ever to visit. Rather, this toxic oasis is merely another point on a grand map, whose roads are light beams crisscrossing the galaxy.
Unmasking Giant Black Holes
Uploaded on Jan 22, 2011
From the NASA Swift team, watch full screen 1080p! Most large galaxies contain a giant central black hole. In an active galaxy, matter falling toward the supermassive black hole powers high-energy emissions so intense that two classes of active galaxies, quasars and blazars, rank as the most luminous objects in the universe. Thick clouds of dust and gas near the central black hole screens out ultraviolet, optical and low-energy (or soft) X-ray light. Although there are many different types of active galaxy, astronomers explain the different observed properties based on how the galaxy angles into our line of sight. We view the brightest ones nearly face on, but as the angle increases, the surrounding ring of gas and dust absorbs increasing amounts of the black hole’s emissions.
Strange Rumblings of a Neutron Star
Uploaded on Jan 18, 2011
The Crab Nebula courtesy of NASA. Created by a supernova seen nearly a thousand years ago, it’s one of the sky’s most famous “star wrecks.” For decades, most astronomers have regarded it as the steadiest beacon at X-ray energies, but data from orbiting observatories show unexpected variations, showing astronomers their hard X-ray “standard candle” isn’t as steady as they once thought. From 1999 to 2008, the Crab brightened and faded by as much as 3.5 percent a year, and since 2008, it has faded by 7 percent. The Gamma-ray Burst Monitor on NASA’s Fermi satellite first detected the decline, and Fermi’s Large Area Telescope also spotted two gamma-ray flares at even higher energies. Scientists think the X-rays reveal processes deep within the nebula, in a region powered by a rapidly spinning neutron star — the core of the star that blew up. But figuring out exactly where the Crab’s X-rays are changing over the long term will require a new generation of X-ray telescopes. From NASA Goddard Space Flight Center
Seeing the Formation of Planets
Uploaded on Jan 7, 2011
See how the Webb Space Telescope will study planetary bodies with our solar system and planets orbiting other stars. Its operations in the years to come promise to help scientists better understand how planets form and how they evolve.
Planets begin as dense knots in clouds of dust swirling around a young star. But how do they go from something like this, to something like this?
With the James Webb Space Telescope astronomers will be able to study how planets come to be and how they change as they get older.
After centuries of searching, astronomers are finding exoplanets just about everywhere. Ranging from giant planets with masses much greater than Jupiter’s to worlds only a few times more massive than Earth.
But where do the planets we know best fit into the menagerie of worlds astronomers are finding? How did our solar system come to be the way it is? Why is Earth a balmy water rich world and are there other worlds like it elsewhere in the galaxy?
These are the kind of questions astronomers will address with Webb. For planets that pass directly in front of their stars, Webb will search for chemical fingerprints, identifying atmospheric gases like water vapor, carbon dioxide, and methane that absorb specific wavelengths of the star’s light. Webb will also study the dusty disks where new planets form to reveal how the chemical compositions of younger and older disks change with time, and identifying how these changes are reflected in the planets we find.
Such studies will be revolutionary in their own right. And by applying Webb’s capabilities closer to home, astronomers will better understand planetary systems.
For example, how do our asteroids, comets, and other small bodies like Pluto relate to the objects that create dusty disks around other stars? The Webb telescope will determine the physical and chemical properties of these bodies with unprecedented sensitivity in wavelengths unavailable to telescopes on the ground.
By learning more about the small bodies in our solar system, scientists will be able to address questions about the solar system’s past, and compare it to other planetary systems we find in similar phases of construction.
For example, did Earth’s oceans arrive by impacts with small icy bodies? If so, is the same process happening elsewhere and can we find those locations? Webb also will study the outer planets and their moons. Of particular interest is Titan, the largest moon of Saturn, now being explored by NASA’s Cassini spacecraft. Titan is as big as the planet mercury, possesses an atmosphere half again as thick as Earth’s, and a frigid surface with lakes of liquid hydrocarbons.
Webb will map Titan’s chemical makeup with six times Cassini’s resolution and monitor the moon’s seasonal changes over a decade or more.
Next stop Uranus. When Voyager 2 returned this image in 1986, the planet’s south pole was facing the sun and few clouds could be seen. But as Uranus neared its equinox in 2007, bright clouds suddenly materialized. So far scientists are at a loss to explain this profound seasonal change.
During Voyager’s visit, the northern hemispheres of Uranus’s big moons were all in shadow. But when Webb begins service, the moons’ northern halves will face the sun and give astronomers abundant new real estate to explore.
Three years later, in 1989, Voyager 2 passed Neptune and imaged its strange dark spot. Over the following years, astronomers have seen the dark spot disappear, and then reappear. Voyager easily picked out clouds despite Neptune’s greater distance from the sun. Why is weather on Neptune and Uranus so different?
Neptune’s big moon Triton is unusual too. Nitrogen-spewing volcanoes and other geological forces reshaped this frozen surface in ways we’re just beginning to understand.
Comets, asteroids, the outer planets and their moons, and beyond them, the icy bodies of the Kuiper belt: these objects provide us with the closest and most detailed look at how our own solar system evolved.
The James Webb Space Telescope makes it possible to take that understanding a step further, to probe the makeup of nearby planetary systems at comparable distances from their stars. Webb will allow astronomers to directly compare the chemical and physical properties of our outer solar system with similar zones around nearby stars.
Imagining Extrasolar Planets
Uploaded on Dec 31, 2010
From the Spitzer Science Center. While astronomers have identified over 500 planets around other stars, they’re all too small and distant to fill even a single pixel in our most powerful telescopes. That’s why science must rely on art to help us imagine these strange new worlds. From Spitzer Space Telescope.
Even without pictures of these exoplanets, astronomers have learned many things that can be illustrated in artwork. For instance, measurements of the temperatures of many “Hot Jupiters,” massive worlds orbiting very close to their stars, hint that their atmospheres may be as dark as soot, glowing only from their own heat.
While “Hot Jupiters” would be relatively dark in visible light, compared to their stars, their brightness is proportionally much greater in the infrared. Illustrating this dramatic contrast change helps explain why the infrared eye of NASA’s Spitzer Space Telescope plays a key role in studying exoplanets.
As our understanding evolves, so must the artwork. Astronomers found a blazing hot spot on the exoplanet Upsilon Andromedae b that at first, appeared to face towards its star. More data has revealed that the hottest area is actually strangely rotated almost 90 degrees away, near the day/night terminator.
WASP 12b is as hot as the filament in a light bulb, and would be blazing bright to our eyes. Most interestingly, if it proves to have a strongly elliptical orbit, as first thought, calculations show it would be shedding some of its outer atmosphere into a gassy disk around its star.
Computer simulations of HD 80606 b, constrained by global infrared measurements, are helping astronomers to better understand the details of how its atmosphere circulates. These computations can feed back into the artwork helping us produce more plausible illustrations.
The closest known exoplanet is 10 light years away in the Epsilon Eridani system. Excess infrared light found here by Spitzer has led astronomers to conclude it also has two asteroid belts, hinting at the possibility of other small, rocky worlds.
Perhaps the strangest known planetary system orbits the pulsar PSR B1257+12, the neutron star remnant of a supernova. Astronomers have detected three planets that either survived the explosion, or formed afterwards in this region filled with spinning magnetic fields and hostile radiation.
Until the day we can explore other star systems as thoroughly as our own, exoplanet art inspired by the real science will help fill in the gaps in our imagination.
Uploaded on Dec 16, 2010
The rapid response system of the Very Large Telescope in Chile goes after fleeting gamma ray bursts, courtesy of ESOCast.
Gamma-ray bursts are among the most energetic events in the Universe, but some appear curiously faint in visible light. The biggest study to date of these so-called dark gamma-ray bursts, using the GROND instrument on the 2.2-meter MPG/ESO telescope at La Silla in Chile, has found that these gigantic explosions don’t require exotic
explanations. Their faintness is now fully explained by a combination of causes, the most important of which is the presence of dust between the Earth and the explosion.
Gamma-ray bursts (GRBs), fleeting events that last from less than a second to several minutes, are detected by orbiting observatories that can pick up their high energy radiation. Thirteen years ago, however, astronomers discovered a longer-lasting stream of less energetic radiation coming from these violent outbursts, which can last for weeks or even years after the initial explosion. Astronomers call this
the burst’s afterglow.
While all gamma-ray bursts  have afterglows that give off X-rays, only about half of them were found to give off visible light, with the rest remaining mysteriously dark. Some astronomers suspected that these dark afterglows could be examples of a whole new class of gamma-ray bursts, while others thought that they might all be at very great distances. Previous studies had suggested that obscuring dust
between the burst and us might also explain why they were so dim.
“Studying afterglows is vital to further our understanding of the objects that become gamma-ray bursts and what they tell us about star formation in the early Universe,” says the study’s lead author Jochen Greiner from the Max-Planck Institute for Extraterrestrial Physics in Garching bei Munchen, Germany.
NASA launched the Swift satellite at the end of 2004. From its orbit above the Earth’s atmosphere it can detect gamma-ray bursts and immediately relay their positions to other observatories so that the afterglows could be studied. In the new study, astronomers combined Swift data with new observations made using GROND  — a dedicated gamma-ray burst follow-up observation instrument, which is attached to the 2.2-meter MPG/ESO telescope at La Silla in Chile. In doing so, astronomers have conclusively solved the puzzle of the missing optical afterglow.
What makes GROND exciting for the study of afterglows is its very fast response time — it can observe a burst within minutes of an alert coming from Swift using a special system called the Rapid Response Mode — and its ability to observe simultaneously through seven filters covering both the visible and near-infrared parts of the spectrum.
By combining GROND data taken through these seven filters with Swift observations, astronomers were able to accurately determine the amount of light emitted by the afterglow at widely differing wavelengths, all the way from high energy X-rays to the near-infrared. The astronomers
used this information to directly measure the amount of obscuring dust that the light passed through en route to Earth. Previously, astronomers had to rely on rough estimates of the dust content .
The team used a range of data, including their own measurements from GROND, in addition to observations made by other large telescopes including the ESO Very Large Telescope, to estimate the distances to
nearly all of the bursts in their sample. While they found that a significant proportion of bursts are dimmed to about 60-80 percent of the original intensity by obscuring dust, this effect is exaggerated for the very distant bursts, letting the observer see only 30-50 percent of the light . The astronomers conclude that most dark gamma-ray bursts are therefore simply those that have had their small
amount of visible light completely stripped away before it reaches us.
Ice Volcano on Titan
Uploaded on Dec 14, 2010
NASA’s Cassini spacecraft has found possible ice volcanoes on Saturn’s moon Titan that are similar in shape to those on Earth that spew molten rock.
Topography and surface composition data have enabled scientists to make the best case yet in the outer solar system for an Earth-like volcano landform that erupts in ice. The results were presented today at the American Geophysical Union meeting in San Francisco.
“When we look at our new 3-D map of Sotra Facula on Titan, we are struck by its resemblance to volcanoes like Mt. Etna in Italy, Laki in Iceland and even some small volcanic cones and flows near my hometown of Flagstaff,” said Randolph Kirk, who led the 3-D mapping work, and is a Cassini radar team member and geophysicist at the U.S. Geological Survey (USGS) Astrogeology Science Center in Flagstaff, Ariz.
Scientists have been debating for years whether ice volcanoes, also called cryovolcanoes, exist on ice-rich moons, and if they do, what their characteristics are. The working definition assumes some kind of subterranean geological activity warms the cold environment enough to melt part of the satellite’s interior and sends slushy ice or other materials through an opening in the surface. Volcanoes on Jupiter’s moon Io and Earth spew silicate lava.
Some cryovolcanoes bear little resemblance to terrestrial volcanoes, such as the tiger stripes at Saturn’s moon Enceladus, where long fissures spray jets of water and icy particles that leave little trace on the surface. At other sites, eruption of denser materials might build up volcanic peaks or finger-like flows. But when such flows were spotted on Titan in the past, theories explained them as non-volcanic processes, such as rivers depositing sediment. At Sotra, however, cryovolcanism is the best explanation for two peaks more than 1,000 meters (3,000 feet) high with deep volcanic craters and finger-like flows.
“This is the very best evidence, by far, for volcanic topography anywhere documented on an icy satellite,” said Jeffrey Kargel, a planetary scientist at the University of Arizona, Tucson. “It’s possible the mountains are tectonic in origin, but the interpretation of cryovolcano is a much simpler, more consistent explanation.”
Kirk and colleagues analyzed new Cassini radar images. His USGS group created the topographic map and 3-D flyover images of Sotra Facula. Data from Cassini’s visual and infrared mapping spectrometer revealed the lobed flows had a composition different from the surrounding surface. Scientists have no evidence of current activity at Sotra, but they plan to monitor the area.
“Cryovolcanoes help explain the geological forces sculpting some of these exotic places in our solar system,” said Linda Spilker, Cassini project scientist at NASA’s Jet Propulsion Laboratory in Pasadena, Calif. “At Titan, for instance, they explain how methane can be continually replenished in the atmosphere when the sun is constantly breaking that molecule down.”
Cosmic Journeys : Is the Universe Infinite?
Uploaded on Nov 23, 2010
Explore the biggest question of all. How far do the stars stretch out into space? And what’s beyond them? In modern times, we built giant telescopes that have allowed us to cast our gaze deep into the universe. Astronomers have been able to look back to near the time of its birth. They’ve reconstructed the course of cosmic history in astonishing detail.
From intensive computer modeling, and myriad close observations, they’ve uncovered important clues to its ongoing evolution. Many now conclude that what we can see, the stars and galaxies that stretch out to the limits of our vision, represent only a small fraction of all there is.
Does the universe go on forever? Where do we fit within it? And how would the great thinkers have wrapped their brains around the far-out ideas on today’s cutting edge?
For those who find infinity hard to grasp, even troubling, you’re not alone. It’s a concept that has long tormented even the best minds.
Over two thousand years ago, the Greek mathematician Pythagoras and his followers saw numerical relationships as the key to understanding the world around them.
But in their investigation of geometric shapes, they discovered that some important ratios could not be expressed in simple numbers.
Take the circumference of a circle to its diameter, called Pi.
Computer scientists recently calculated Pi to 5 trillion digits, confirming what the Greeks learned: there are no repeating patterns and no ending in sight.
The discovery of the so-called irrational numbers like Pi was so disturbing, legend has it, that one member of the Pythagorian cult, Hippassus, was drowned at sea for divulging their existence.
A century later, the philosopher Zeno brought infinity into the open with a series of paradoxes: situations that are true, but strongly counter-intuitive.
In this modern update of one of Zeno’s paradoxes, say you have arrived at an intersection. But you are only allowed to cross the street in increments of half the distance to the other side. So to cross this finite distance, you must take an infinite number of steps.
In math today, it’s a given that you can subdivide any length an infinite number of times, or find an infinity of points along a line.
What made the idea of infinity so troubling to the Greeks is that it clashed with their goal of using numbers to explain the workings of the real world.
To the philosopher Aristotle, a century after Zeno, infinity evoked the formless chaos from which the world was thought to have emerged: a primordial state with no natural laws or limits, devoid of all form and content.
But if the universe is finite, what would happen if a warrior traveled to the edge and tossed a spear? Where would it go?
It would not fly off on an infinite journey, Aristotle said. Rather, it would join the motion of the stars in a crystalline sphere that encircled the Earth. To preserve the idea of a limited universe, Aristotle would craft an historic distinction.
On the one hand, Aristotle pointed to the irrational numbers such as Pi. Each new calculation results in an additional digit, but the final, final number in the string can never be specified. So Aristotle called it “potentially” infinite.
Then there’s the “actually infinite,” like the total number of points or subdivisions along a line. It’s literally uncountable. Aristotle reserved the status of “actually infinite” for the so-called “prime mover” that created the world and is beyond our capacity to understand. This became the basis for what’s called the Cosmological, or First Cause, argument for the existence of God.
A Look at the Milky Way’s Birth
Uploaded on Nov 12, 2010
From NASA Astrophysics. Supercomputer visualization shows small galaxies forming, interacting, and merging to form a Milky Way-type galaxy with spiral arms.
How the Universe Evolved
Uploaded on Nov 5, 2010
From NASA’s James Webb Telescope, ultra high-end supercomputer simulations show how gravity drew primitive galaxies together to form the large scale structures of our universe. Revel in these awe-inspiring visualizations produced by the Advanced Visualization Lab at the National Center for Supercomputing Applications/ University of Illinois and the MPE in Germany.
A Look at the Milky Way’s Future
Uploaded on Nov 4, 2010
From NASA, here’s a vivid look at the future of our Milky Way in an ultra high-end computer simulation of spiral galaxies colliding. Collisions and mergers are central to galaxy evolution, from the earliest dwarf galaxies that formed to the familiar galaxies we see today. These collisions in action will be targets for the James Webb Telescope. Astronomers hope to understand how the shape, structure and chemical content of galaxies change over the sweep of cosmic history.
How Solar Systems & Planets Evolve
Uploaded on Nov 3, 2010
From NASA’s James Webb Telescope, feast on this gorgeous, ground-breaking visualization that explores how stars form in dense dusty regions of our galaxy such as the Eagle nebula. With its huge mirror, the James the Webb Space Telescope will be able to see inside these dense clouds of gas and dust. From NASA. Visualizations by Donna Cox and her team at the Advanced Visualization Lab of the National Center for Supercomputing Applications, University of Illinois.
New Look at the Infant Universe
Uploaded on Oct 29, 2010
From ESA’s HubbleCast. In early 2009, a team of astronauts visited Hubble to repair the wear and tear of twenty years of operating in a hostile environment — and to install two new instruments, the Cosmic Origins Spectrograph, and Wide Field Camera 3 — better known as WFC3.
Hubble has become famous for its striking visible-light pictures of huge clouds of interstellar dust and gas. But sometimes scientists want to know what’s happening behind, or inside, the cloud of dust. Making infrared observations pulls away the veil and reveals the hidden stars.
Until now, infrared imaging was challenging with Hubble. The Near Infrared Camera and Multi-object Spectrometer, or NICMOS, did allow astronomers to study objects in infrared light in ways not possible from the ground, but it forced them to make a difficult choice. Because its images were small — only about 65 000 pixels in total, similar to a mobile phone screen — NICMOS could produce the sharpest images only if it concentrated on a very narrow field of view. Taking in a wider view came at the cost of losing much of the detail.
These improvements mean Hubble is now far better at observing large areas of sky as well as very faint and very distant objects. These are key for the science of cosmology, the study of the origins and development of the Universe.
Because the Universe is expanding, light waves coming from distant objects are stretched as they travel through space, and the waves become longer. The further an object is away, the more its light is stretched on its journey to us, and the redder the light appears. Hence the effect is known as redshift.
For really distant objects, the ultraviolet and visible light is redshifted so much it goes infrared — literally, “below red” — and that is the reason that infrared imaging is so important for spotting these very distant galaxies.
This is the Hubble Ultra Deep Field, a visible light image taken in 2003 and 4 with Hubble’s Advanced Camera for Surveys. The picture is of a little patch of sky almost a hundred times smaller than the area of the full moon. It contains no stars visible with the naked eye — but taking a million second exposure of this little black speck of space reveals these vanishingly faint faraway galaxies.
Studying the same region with WFC3’s infrared photography reveals galaxies more distant still: some of these are so far away that they have been redshifted out of the visible spectrum altogether.
We see galaxies here as they were many billions of years ago. When the light from some of these galaxies started its long journey towards us, our Sun and Earth had not even begun to form.
But what is really exciting cosmologists about WFC3’s infrared imaging of the Hubble Ultra Deep Field is not just what’s in the foreground so to speak, amazing as that is, but the scatter of tiny, faint specks just visible in the background, beyond these already faraway galaxies.
Some of the flecks of light in this fuzzy image are just anomalies within the light detectors, but among them are faint impressions of early galaxies. In this photo we are looking at some of the most remote objects ever seen.
They are so distant, and their light has travelled so far to reach us, that we see these galaxies as they were 13 billion years ago, when the Universe was only about 5% of its current age.
Discovering and studying these galaxies can tell us a lot about the conditions that prevailed in the earliest years of the Universe, and confirm — or perhaps refute — our theories of early galaxy formation.
Rendezvous with a Comet
Uploaded on Oct 28, 2010
From JPL. Comets are important because they represent the leftover bits and pieces from the outer solar system formation process, which took place four and a half billion years ago. As the planets formed, the first thing you got was tiny clumps of dust in the inner solar system, and in the outer system, dust and ice.
The comets are what made the cores of Jupiter, Saturn, Uranus and Neptune. But the planets are so hot that the chemistry changes completely, whereas the comets have remained frozen the entire time so that the chemistry is preserved. Comets are basically made up of a number of different regions; a dirty ice ball, relatively small and black. When it gets near the sun these ices start vaporizing, which forms a atmosphere. And then, when some of these dust particles are blown back away from the sun because of the pressure of sunlight, you form a dust tail and often a gas or ion tail.
Comets and asteroids have always gotten bad press. The dinosaurs checked out 65 million years ago because of an asteroid impact. But what we don’t hear about, is how important these objects are in terms of bringing the building blocks of life to the early planet. Comets almost certainly brought most of the organic material and much of the water to Earth.
In a sense, we wouldn’t even be here without comets and asteroids. Scientists like to put objects in boxes. Comets should look this way. Asteroids should look this way. But Mother Nature keeps knocking the boxes over and saying, no it doesn’t look that way. The few comets that we’ve seen, they all are very different from one another. So the question is, are all these objects different from one another? The Epoxi mission is an extended mission for the Deep Impact flyby spacecraft. After we went past comet Temple 1 and drove an impactor into it, we spent a year or more observing extrasolar planets and we are now on target for a flyby of comet Hartley 2. Which is interesting in the sense that it’s one of the smallest objects we’ve seen and it’s thought to be active over 100% of its surface. If we understand the comets really well, it will tell us how all the planets got made. That’s why we choose comets to study.
Curious ExoPlanet Hot Spot
Uploaded on Oct 22, 2010
From the Spitzer Science Center: The gas-giant planet, named upsilon Andromedae b, orbits tightly around its star, with one face perpetually boiling under the star’s heat. It belongs to a class of planets termed hot Jupiters, so called for their scorching temperatures and large, gaseous constitutions.
One might think the hottest part of these planets would be directly under the sun-facing side, but previous observations have shown that their hot spots may be shifted slightly away from this point. Astronomers thought that fierce winds might be pushing hot, gaseous material around.
But the new finding may throw this theory into question. Using Spitzer, an infrared observatory, astronomers found that upsilon Andromedae b’s hot spot is offset by a whopping 80 degrees. Basically, the hot spot is over to the side of the planet instead of directly under the glare of the sun.
“We really didn’t expect to find a hot spot with such a large offset,” said Ian Crossfield, lead author of a new paper about the discovery appearing in an upcoming issue of Astrophysical Journal. “It’s clear that we understand even less about the atmospheric energetics of hot Jupiters than we thought we did.”
The results are part of a growing field of exoplanet atmospheric science, pioneered by Spitzer in 2005, when it became the first telescope to directly detect photons from an exoplanet, or a planet orbiting a star other than our sun. Since then, Spitzer, along with NASA’s Hubble Space Telescope, has studied the atmospheres of several hot Jupiters, finding water, methane, carbon dioxide and carbon monoxide.
In the new study, astronomers report observations of upsilon Andromedae b taken across five days in February of 2009. This planet whips around its star every 4.6 days, as measured using the “wobble,” or radial velocity technique, with telescopes on the ground. It does not transit, or cross in front of, its star as many other hot Jupiters studied by Spitzer do.
Spitzer measured the total combined light from the star and planet, as the planet orbited around. The telescope can’t see the planet directly, but it can detect variations in the total infrared light from the system that arise as the hot side of the planet comes into Earth’s field of view. The hottest part of the planet will give off the most infrared light.
One might think the system would appear brightest when the planet was directly behind the star, thus showing its full sun-facing side. Likewise, one might think the system would appear darkest when the planet swings around toward Earth, showing its backside. But the system was the brightest when the planet was to the side of the star, with its side facing Earth. This means that the hottest part of the planet is not under its star. It’s sort of like going to the beach at sunset to feel the most heat. The researchers aren’t sure how this could be.
They’ve guessed at some possibilities, including supersonic winds triggering shock waves that heat material up, and star-planet magnetic interactions. But these are just speculation. As more hot Jupiters are examined, astronomers will test new theories.
“This is a very unexpected result,” said Michael Werner, the Spitzer project scientist at NASA’s Jet Propulsion Laboratory, Pasadena, Calif., who was not a part of the study. “Spitzer is showing us that we are a long way from understanding these alien worlds.”
The Most Distant Galaxy in the Universe So Far
Uploaded on Oct 21, 2010
From ESOCast: An international team of astronomers using ESO’s Very Large Telescope has measured the distance to the most remote galaxy so far. This is the first time that astronomers have been able to confirm that they are observing a galaxy as it was in the era of reionization — when the first generation of brilliant stars was making the young Universe transparent and ending the cosmic Dark Ages.
We are going to find out how a team of astronomers used ESO’s Very Large Telescope, the VLT, to confirm that a galaxy that had previously been spotted in images from the NASA/ESA Hubble Space Telescope is in fact the most distant object that is ever been identified in the Universe.
Studying these first galaxies is extremely difficult; they are very faint and small and by the time their dim light gets to Earth it falls mostly in the infrared part of the spectrum because it has been stretched by the expansion of the Universe.
To make matters worse, at this very early time, less than a billion years after the Big Bang, the Universe was not completely transparent. It was filled with hydrogen which acted kind of like a fog and absorbed the ultraviolet radiation from the young galaxies.
So, holding the record for having measured the redshift of the most distant object in the Universe is not just a trophy to hang on the wall, it does have important astrophysical implications. This is the first time that we’ve managed to obtain spectroscopic observations of a galaxy from the era of reionization, in other words from the time when the Universe was still clearing out the hydrogen fog.
Despite the difficulties of finding these early galaxies, the new Wide Field Camera 3 on the NASA/ESA Hubble Space Telescope discovered several very good candidate objects earlier in 2010.
They were thought to be galaxies shining in the early Universe at redshifts greater than eight, but confirming the distances to such faint and remote objects is an enormous challenge and can only reliably be done using spectroscopy from very large ground-based telescopes.
The team was excited to find that if you combine the huge light collecting power of the VLT, with the sensitivity of its infrared spectroscopic instrument, SINFONI, and if you then use a very long exposure time you just might be able to detect the faint glow from one of these very remote objects and then go on to measure its distance.
A 16 hour exposure with the VLT and SINFONI of the galaxy UDFy-38135539 did indeed show the very faint glow from hydrogen at a redshift of 8.6, which means that this light left the galaxy when the Universe was only about 600 million years old. This is the most distant galaxy ever reliably confirmed.
One of the puzzling things about this discovery is that the ultraviolet radiation emitted by the galaxy does not actually seems to be strong enough to be able to clear out the hydrogen fog around the galaxy.
So one possible explanation is that there must be other galaxies, probably fainter and less massive neighbours, that helped ionize the hydrogen in the region of space around the galaxy, thus making it transparent.
Without this additional help the brilliant light from the main galaxy would have been trapped in the surrounding hydrogen fog and it could not have even started its 13 billion-year journey towards Earth.
Studying the era of reionization and the formation of the first galaxies is really pushing the capability of current telescopes and instruments to the limit. But, this will be exactly the type of science that ESO’s European Extremely Large Telescope will excel at. Once operational, this will be the largest optical and infrared telescope in the world.
Uploaded on Oct 15, 2010
Recently astronomers used the Suzaku orbiting X-ray observatory, operated jointly by NASA and the Japanese space agency, to discover the largest known reservoir of rare metals in the universe. Suzaku detected the elements chromium and manganese while observing the central region of the Perseus galaxy cluster. The metallic atoms are part of the hot gas, or “intergalactic medium,” that lies between galaxies.
Thumbnail: “The Robot (3) 20102007 Inspired by Hajime Sorayama by Emile Noordeloos.”
Exploding stars, or supernovas, forge the heavy elements. The supernovas also create vast outflows, called superwinds. These galactic gusts transport heavy elements into the intergalactic void.
What is the universe made of? The vast majority of it consists of the wispy cosmic lightweights hydrogen and helium. Everything else on the periodic table contributes only a small fraction of the whole.
Elements heavier than hydrogen and helium are forged in stars, and during their explosive deaths as supernovas.
Type 1a supernovas are nature’s most productive foundries. An old white dwarf star pulls gas off its giant neighbor. The dwarf gains mass until it becomes unstable and blows itself to bits.
The explosion creates vast amounts of heavy elements and blasts them into space.
Suzaku is an orbiting X-ray observatory, operated jointly by NASA and the Japanese Space Agency. And it recently spotted the metals chromium and manganese in intergalactic space for the first time. It’s the largest known concentration of rare metals in the universe.
Suzaku was looking at X-rays shining from the core region of the Perseus galaxy cluster and detected the metals in hot, thin intergalactic gas.
The gas is so thin it’s close to a vacuum, but it fills a volume of space in the cluster about 1.4 million light years across. [
Supernovas forged the metals and blasted them out of the galaxies, but a single stellar explosion wasn’t powerful enough to get the job done. That requires periods of higher than normal star birth and death.
These so-called starbursts stirred up vast outflows of matter called superwinds. Heavy elements forged by supernovas rode the superwinds to intergalactic space. A single supernova can produce thousands of times Earth’s mass in chromium.
The Suzaku astronomers estimate that it took some three billion supernovas to forge the treasure trove they found in the Perseus Cluster.
The total reservoir of heavy metal discovered by Suzaku is even more staggering. The Perseus core region holds 30 millions times the Sun’s mass in chromium. About 10 trillion times the mass of Earth.
Suzaku’s chemical census of the universe is just beginning, but it’s already revealed just how rare and precious some corners of the
Search for Asteroid Threats
Uploaded on Oct 12, 2010
What is the true long-term threat of Near Earth Objects? NASA defines “potentially hazardous” as a Near Earth Object that will pass within .05 AU from Earth and is at least 140 meters in diameter. (http://neo.jpl.nasa.gov/neo/pha.html)
But consider the damage left by a 30-meter object in the famed Siberian impact of 1908:
“Recent scientific studies by meteorite researcher Christopher Chyba have estimated that the Tunguska event may have been caused by the explosion of a stony meteroid about 30 meters in diameter traveling at about 15 km/s. Compare the energy released by such an object with that of an atomic bomb such as those dropped on Japan in World War II.”
The truth is no one really knows how many asteroids this size or larger are out there. According to NASA sources, the population breaks down as follows:
100 meters in diameter: 300,000
500 meters in diameter: 10,000
Over one kilometer in diameter: 500-1,000
The good news is that eight projects are at work to search for them, including NASA’s NEO-Wise space telescope, and more are coming on line soon. The bad news is that fewer than 8,000 of these have been discovered so far.
Mapping the History of Space & Time
Uploaded on Oct 4, 2010
The longer a telescope spends looking at a target, the more sensitive the observations become, and the deeper we can look into space. But to get the full picture of what’s happening in the Universe, astronomers also need observations at a range of different wavelengths, requiring different telescopes. These are the key ideas behind the Great Observatories Origins Deep Survey, or GOODS for short.
The GOODS project unites the world’s most advanced observatories, these include ESO’s Very Large Telescope, the NASA/ESA Hubble Space Telescope, the Spitzer Space Telescope, the Chandra X-ray Observatory and many more, each making extremely deep observations of the distant Universe, across the electromagnetic spectrum. By combining their powers and observing the same piece of the sky, the GOODS observatories are giving us a unique view of the formation and evolution of galaxies across cosmic time, and mapping the history of the expansion of the Universe.
Now, this is not the first time that telescopes have been used to give us extremely deep views of the cosmos. For example, the Hubble Deep Field is a very deep image of a small piece of sky in the northern constellation of Ursa Major. This revealed thousands of distant galaxies despite the fact that the whole field is actually only a tiny speck of the sky, about the size of a grain of sand held at arm’s length.
Now, with GOODS, many different observatories have brought their powers to bear on two larger targets, one centered on the original Hubble Deep Field in the northern sky, and one centred on a different deep target, the Chandra Deep Field South, in the southern sky.
The main GOODS fields are each 30 times larger than the Hubble Deep Field, and additional observations cover an area the size of the full Moon.
These areas of the sky were already some of the most extensively explored, and so the combination of existing archival data and many new, dedicated observations gives us an unprecedented view of of the history of galaxies.
Alien’s View of Our Solar System
Uploaded on Sep 23, 2010
From NASA Astrophysics… a supercomputer simulation shows how alien astronomers might have seen the formation of our solar system. Dust ground off icy bodies in the Kuiper Belt, the cold-storage zone that includes Pluto and millions of other objects, creates a faint infrared disk potentially visible to alien astronomers looking for planets around the sun. Neptune’s gravitational imprint on the dust is always detectable in new simulations of how this dust moves through the solar system. By ramping up the collision rate, the simulations show how the distant view of the solar system might have changed over its history.
Craters Reveal the Moon’s Turbulent Early History
Uploaded on Sep 16, 2010
Results from NASA’s Lunar Reconnaissance Orbiter showing the ages of craters on the moon. The larger the crater, the older it is. This shows that the moon was bombarded by larger objects in its early years. This suggests that the Earth was subject to the same pattern or larger, more violent impacts the deeper you go into its past.
Cosmic Energy: Cold Sparks to Black Holes
Uploaded on Sep 10, 2010
What’s the hottest place in the universe? What’s it like inside a Black Hole? This video climbs the power scales of the universe, from the coldest and bleakest reaches of our galaxy on out to the hottest and most violent places known. How and where do Earth and humanity fit within the immensely powerful scales that define our universe?
All across the immense reaches of time and space, energy is being exchanged, transferred, released, in a great cosmic pinball game we call our universe.
To see how energy stitches the cosmos together, and how we fit within it, we now journey through the cosmic power scales of the universe, from atoms nearly frozen to stillness. To Earth’s largest explosions. From stars colliding, exploding, to distant centers of power so strange, and violent, they challenge our imaginations.
Today, energy is very much on our minds, as we search for ways to power our civilization and serve the needs of our citizens. But what is energy? Where does it come from? And where do we stand within the great power streams that shape time and space?
Energy comes from a Greek word for activity or working. In physics, it’s simply the property or the state of anything in our universe that allows it to do work. Whether it’s thermal, kinetic, electro-magnetic, chemical, or gravitational.
The 19th century German scientist Hermann von Helmholtz found that all forms of energy are equivalent, that one form can be transformed into any other. The laws of physics say that in a closed system – such as our universe – energy is conserved. It may be converted, concentrated, or dissipated, but it’s never lost.
Humans today generate about two and a half trillion watts of electrical power. How does that stack up to the power generated by planet Earth? Deep inside our planet, the radioactive decay of elements such as uranium and thorium generates 44 trillion watts of power. As this heat rises to the surface, it drives the movement of Earth’s crustal plates, and powers volcanoes.
Remarkably, that’s just a fraction of the energy released by a large hurricane in the form of rain. At the storm’s peak, it can rise to 600 trillion watts. A hurricane draws upon solar heat collected in tropical oceans in the summer. You have to jump another power of ten to reach the estimated total heat flowing through Earth’s atmosphere and oceans from the equator to the poles, and another two to get the power received by the Earth from the sun, at 174 quadrillion watts.
Believe it or not, there’s one human technology that has exceeded this level. The AN602 hydrogen bomb was detonated by the Soviet Union on October 30, 1961. It unleashed some 1400 times the combined power of the Nagasaki and Hiroshima bombs. With a blast yield of up to 57,000 tons of TNT, it generated 5.3 trillion trillion watts, if only for a tiny fraction of a second. That’s 5.3 Yottawatts, a term that will come in handy as we now begin to ascend the power scales of the universe.
To Nikolai Kardashev, a Level 2 civilization would achieve a constant energy output 80 times higher than the Russian superbomb. That’s equivalent to the total luminosity of our sun, a medium-sized star that emits 375 yottawatts. However, in the grand scheme of things, our sun is but a cold spark in a hot universe. Look up into Southern skies and you’ll see the Large Magellanic Cloud, a satellite galaxy of our Milky Way.
Deep within is the brightest star yet discovered. R136a1 is 10 million times brighter than the sun. Now if that star happened to go supernova, at its peak, it would blast out photons with a luminosity of around 500 billion yottawatts. To advance to a level three civilization, you have to marshal the power of an entire galaxy. The Milky Way, with about two hundred billion stars, has an estimated total luminosity of 3 trillion yottawatts, a three followed by 36 zeros.
To boldly go beyond Level 3, a civilization would need to marshal the power of a quasar. A quasar is about a thousand times brighter than our galaxy. Here is where cosmic power production enters a whole new realm, based on the physics of extreme gravity. It was Isaac Newton who first defined gravity as the force that pulls the apple down, and holds the earth in orbit around the sun. Albert Einstein redefined it in his famous General Theory of Relativity.
Gravity isn’t simply the attraction of objects like stars and planets, he said, but a distortion of space and time, what he called space-time. If space-time is like a fabric, he said, gravity is the warping of this fabric by a massive object like a star. A planet orbits a star when it’s caught in this warped space, like a ball spinning around a roulette wheel.
Sensational Solar System Discovery
Uploaded on Aug 24, 2010
Astronomers working with the super planet finding HARPS instrument at the La Silla Observatory in Chile, have discovered a remarkable extrasolar planetary system that has some striking similarities to our own Solar System. At least five planets are orbiting the Sun-like star HD 10180, and the regular pattern of their orbits is similar to that observed for our neighbouring planets. One of the new extrasolar worlds could be only 1.4 times the mass of the Earth, making it the least massive exoplanet ever found.
Viking First Views of Mars
Uploaded on Aug 20, 2010
A Titan 3/Centaur rocket launched NASA’s Viking 1 spacecraft on a 505-million-mile journey to Mars on Aug. 20, 1975. Viking 2 followed three weeks later.
Each mission included both an orbiter and a lander, and all four components accomplished successes. On July 20, 1976, the Viking 1 lander returned the first photograph taken on the surface of Mars. That lander in a region called Chryse Planitia operated until Nov. 13, 1982. The Viking 2 lander operated in the Utopia Planitia region from Sept. 3, 1976 to April 11, 1980. The orbiters sent home images of the entire planet at resolutions of 300 meters or less per pixel.
New High-Intensity Cosmic Explosion
Uploaded on Aug 13, 2010
The Fermi Gamma Ray Space Telescope picked up a whole new type of cosmic explosion: a ultra high-intensity explosion coming from the surface of a white dwarf star. The finding stunned observers and theorists alike because it overturns a long-standing notion that such novae explosions lack the power for such high-energy emissions.
In March, Fermi’s Large Area Telescope (LAT) detected gamma rays — the most energetic form of light — from the nova for 15 days. Scientists believe that the emission arose as a million-mile-per-hour shock wave raced from the site of the explosion. A nova is a sudden, short-lived brightening of an otherwise inconspicuous star. The outburst occurs when a white dwarf in a binary system erupts in an enormous thermonuclear explosion.
Lurking Dragon, Cosmic Swan
Uploaded on Aug 6, 2010
A beautiful nugget from Spitzer’s “Hidden Universe.” Behind a dark veil of dust in the constellation Sagittarius, a lurking dragon has been revealed by the infrared eye of NASA’s Spitzer Space Telescope.
The red dots along its dark filaments are baby stars forming at a furious rate. The dark Dragon appears to fly away from M17, its brightly glowing neighbor known alternately as the Omega or Swan nebula. Oddly, astronomers have found that both the Dragon and the Swan are forming roughly the same numbers of stars.
If so, why should they look so different from one another? The answer may be that dragons, rather than ugly ducklings, grow up to become swans. While the Dragon is forming fairly large type B stars, only in the Swan do we find the very largest O stars. Their brilliant glare illuminates and disperses the dust, creating a nebula that is equally vivid in infrared and visible light.
The gas and dust clouds in this region appear to be passing through the Sagittarius spiral arm, a kind of gravitational traffic jam. Astronomers have long believed clouds will bunch up when they enter a spiral arm, triggering the gravitational collapse needed to form stars. When the first generation of smaller stars form in the Dragon, they seem to further compress the nearby dust.
This enables a second generation of even more massive O stars to form and light up the area, destroying the surrounding dust clouds. Further downstream from the Swan, a cluster of O stars sits at the center of a blown-out bubble.
This is likely the fading remains of an older nebula, now largely dispersed as it exits the other side of the spiral arm. In this one picture, Spitzer has captured a snapshot of the evolution of a star-forming region. From Dragon, to Swan, to bubble, it heralds a new generation of Milky Way stars.
Saturn’s Ring Disturber
Uploaded on Jul 30, 2010
While orbiting Saturn for the last six years, NASA’s Cassini spacecraft has kept a close eye on the collisions and disturbances in the gas giant’s rings. They provide the only nearby natural laboratory for scientists to see the processes that must have occurred in our early solar system, as planets and moons coalesced out of disks of debris.
New images from Cassini show icy particles in Saturn’s F ring clumping into giant snowballs as the moon Prometheus makes multiple swings by the ring. The gravitational pull of the moon sloshes ring material around, creating wake channels that trigger the formation of objects as large as 20 kilometers (12 miles) in diameter.
Saturn’s thin, kinky F ring was discovered by NASA’s Pioneer 11 spacecraft in 1979. Prometheus and Pandora, the small “shepherding” moons on either side of the F ring, were discovered a year later by NASA’s Voyager 1. In the years since, the F ring has rarely looked the same twice, and scientists have been watching the impish behavior of the two shepherding moons for clues.
Prometheus, the larger and closer to Saturn of the two moons, appears to be the primary source of the disturbances. At its longest, the potato-shaped moon is 148 kilometers (92 miles) across. It cruises around Saturn at a speed slightly greater than the speed of the much smaller F ring particles, but in an orbit that is just offset. As a result of its faster motion, Prometheus laps the F ring particles and stirs up particles in the same segment once in about every 68 days.
“Some of these objects will get ripped apart the next time Prometheus whips around,” Murray said. “But some escape. Every time they survive an encounter, they can grow and become more and more stable.”
Cassini scientists using the ultraviolet imaging spectrograph previously detected thickened blobs near the F ring by noting when starlight was partially blocked. These objects may be related to the clumps seen by Murray and colleagues.
The newly-found F ring objects appear dense enough to have what scientists call “self-gravity.” That means they can attract more particles to themselves and snowball in size as ring particles bounce around in Prometheus’s wake, Murray said. The objects could be about as dense as Prometheus, though only about one-fourteenth as dense as Earth.
What gives the F ring snowballs a particularly good chance of survival is their special location in the Saturn system. The F ring resides at a balancing point between the tidal force of Saturn trying to break objects apart and self-gravity pulling objects together. One current theory suggests that the F ring may be only a million years old, but gets replenished every few million years by moonlets drifting outward from the main rings. However, the giant snowballs that form and break up probably have lifetimes of only a few months.
The new findings could also help explain the origin of a mysterious object about 5 to 10 kilometers (3 to 6 miles) in diameter that Cassini scientists spotted in 2004 and have provisionally dubbed S/2004 S 6. This object occasionally bumps into the F ring and produces jets of debris.
“The new analysis fills in some blanks in our solar system’s history, giving us clues about how it transformed from floating bits of dust to dense bodies,” said Linda Spilker, Cassini project scientist at NASA’s Jet Propulsion Laboratory in Pasadena, Calif. “The F ring peels back some of the mystery and continues to surprise us.”
The Unbearable Beauty of the Night Sky
Uploaded on Jul 22, 2010
Take a DEEP BREATH before watching this ESOCast mashup with Dr. J. The Sun is setting behind Cerro Paranal in the Chilean Atacama desert. While astronomers get ready to observe with ESO’s Very Large Telescope, Nature prepares for her own grand display. As night falls over the desert, the southern sky reveals its nocturnal beauty, leaving the spectator in silent amazement. Some people, however, don’t just stare at the spectacle. With great skill, they record these unique moments for everyone to see – they are the photographers of the night.
Anyone who has been up at night in a remote, high place such as at one of ESO’s observatories in Chile may have been lucky enough to experience the splendid view of the myriad stars shining brightly from the heavens. It is a both a dream and a challenge for a photographer to capture an image of this incredible view. Today we will focus on three ESO staff members, who, during their free time, produce outstanding astrophotography. By publishing their results on the internet they share their enthusiasm for the astonishing wonders of the southern skies with a wider audience.
Yuri Beletsky is an ESO Fellow and astronomer at the Paranal Observatory.
When not observing with the world’s most advanced telescope, the VLT, he actively lives out his passion for taking pictures of the southern sky.
“I like the night sky, I like stars and the night sky is so beautiful, you can see millions of stars and astrophotography is the best way to show the people what actually stars are, so taking this picture I share my passion with people and I am showing the sky then.”
Over time, Yuri has produced many spectacular images of Paranal against the wonderful backdrop of the night sky.
A laser beam shooting out of one of the VLT _s Unit Telescopes.
The bright constellation of the Southern Cross.
The Pipe Nebula with its picturesque dust lane crossing the Milky Way.
Sunlight reflected by small particles of dust lying in between the planets causes the faint zodiacal light.
Paranal is an ideal site for astrophotographers as it offers crystal-clear, extremely dark skies with perfect weather conditions on about 320 nights per year.
Gerhard Hüdepohl, an electronic engineer at Paranal knows about the photographic benefits of the VLT _s site.
Gerhard, who is also a renowned photographer of Chile’s landscape, combines the beauty of the Atacama desert with the shining Milky Way in a unique way.
“My favourite type of photography is landscape photography and in particular images of the landscape at night, showing the Milky Way in the night sky here in the Atacama desert. And here at Paranal I can have the telescopes as a nice foreground and the stars and the night sky as a background”.
The bright plane of our Milky Way as it arches above the VLT. An image like this can only be obtained under top-notch stargazing conditions, such as those offered at Paranal.
Like Yuri, Gerhard has also produced a spectacular series of images showing the VLT with its laser beam and the night sky.
“I am always trying to show Paranal from new, fresh points of view, different angles, different times of the day, so I am always thinking about new ideas. So that is my plan for the future”.
Astrophotography is very demanding. The photographer has to stay out in the dark and in the chill of the night for many hours. Sometimes it can take several nights of painstaking work in these tough conditions to obtain just one image and the equipment must always function flawlessly.
Stéphane Guisard is the head of the optical group at Paranal. His astrophotography benefits from his professional expertise as an optical engineer specialising in telescopes.
“I take pictures of galaxies and nebulae with a telescope, but I also like to take wide-field images of the sky with a terrestrial foreground. I like to share the beauty of the sky and the Universe with people.”
This photographic mosaic of the central parts of our galactic home is just one example of Stéphane’s work. Taken with an amateur telescope coupled to a CCD camera, the image combines about 1200 photos for a total exposure time of around 250 hours.
Stéphane has also produced a spectacular series of timelapse sequences at the Paranal site. Producing such sequences is quite a challenge as the images must be taken at regular intervals, and all the parameters must match perfectly to obtain the sensation of the moving firmament.
There is no doubt that Yuri, Gerhard and Stéphane will continue to produce stunning images of the starry skies above Paranal. The wonderful quality of the images is a testament to the splendour of the night sky at ESO’s Paranal Observatory. By sharing their work, these three astrophotographers have brought their magnificent view of the southern sky to a wider audience.
Earth & Titan
Uploaded on Jul 17, 2010
NASA JPL scientists look for Earthly examples of the terrain features they’ve been seeing on Saturn’s moon Titan, including the dry landscapes of Death Valley, California. From NASA’s Jet Propulsion Laboratory.
Since we’re probably never going to get to the surface of Titan and be able to pick up the rocks and take samples of the liquid, we wanted to be able to understand a place that we can get to, and then draw conclusions about Titan.
We believe that geology is geology everywhere. So we’ve come to Death Valley, to Racetrack Playa. It’s a dry lake right now, but it’s a lake nonetheless; so we can look for similar pieces of evidence. The reason we do that is we can crawl around Death Valley and measure things. We could find out what’s happening and find out what causes that evidence to occur. And it’s just like a detective game from there on.
So whenever you have a high thing next to a low thing, you can be sure that something’s going to happen. Nature likes to even itself out. On Ontario Lacus, we have high things right next to low things. So the rainfall is going to move the material from the high to the low and it’s going to form these same alluvial fans where material washes out from the gully like it does here, and it’s going to flow the material down to the lakebed.
At Ontario Lacus, there are pieces of bedrock like this, only probably made out of water ice, that make fingers that extend down into the lake. It’s as though the lake had risen up and flooded those valleys. Now this is a much smaller example than we see on Ontario Lacus, but it tells us that the level of the water is what has made this into a finger, not the finger itself.
On Titan, we think that the lakes are filled by seasonal drainages. Sometimes, those drainages make cross-hatch patterns that look like gullies. So we looked on Earth for a place that has those cross-hatch gullies, and here we find it at Racetrack Playa. Water that comes down from those hills flows in infrequent but violent thunderstorms out onto Racetrack Playa. As the rainfall comes down closer to the playa, on Titan, they form deltas, something like the Mississippi Delta out there.
This is a dry lakebed, so what happens is that the gravel just gets pushed out onto the lakebed. And that’s a clue, that what’s happening on Titan is a fluid, not a dry lakebed. So by studying the relationship between the evidence and the events here in Death Valley,where we can measure them, we can connect that same set of evidence to the events that might have happened on Titan.
It’s important because if we’re going to find life somewhere else in the universe, it has to have something in common with the once place that we know has life, and that’s here.
Universe Painted in Light
Uploaded on Jul 14, 2010
Check out the unusual visual style in this adaptation of the ground-breaking “Science on a Sphere” production, including depictions of Earth. From NASA and NOAA, with additional images from ESA Hubble.
We perceive light–we see it—but what we see and what it means are not the same. Without context, detail means nothing.
Oh, there are so many factors at play here: what wavelengths of light can we see, how well can our brains take what we see and turn it into something we understand?
And also, how do we compare ourselves to the thing we’re observing? What tools do we use to help us capture information? How do we turn light into data, data into pixels, pixels into meaning? Start with a planet.
For example, Earth. And as long as we’re at it, let’s tip the Earth to spin properly on its axis. Now, recall our original points of light. Our idea.
These are satellites in orbit. Satellites collect data as the Earth rotates beneath them.
Think of satellites as paint brushes working in reverse: instead of painting planets with light, satellites collect light reflected from planets below. With enough data we can paint a world.
Data that make this image come from instruments on two NASA satellites called AQUA and TERRA. These instruments see the Earth in what we might regard as “natural color.”
They can also see certain events as they happen. There, splattered like white paint on a blue canvas, something important: Hurricane Katrina.
These satellites are only two of many that can see hurricanes. The stripes you see building up come from a unique spacecraft called TRMM. Among the many remarkable things TRMM can do, it can look inside hurricanes like nothing else in the world.
See for yourself. TRMM sees the actual body of the beast in three dimensions. Orange and red zones indicate higher rainfall rates. Cloud spires called hot towers drive the storm’s greedy grab for energy.
The Earth changes. It breathes. And it surprises. Though we live on a planet largely covered by water, we often forget that huge tracts are frozen solid. Let’s change the perspective.
Ice covers much of the world. The eternally frozen parts are called the Cryosphere. It’s the planet’s thermostat, and a hydrological warehouse, and in terms of a changing climate, it’s the canary in a coalmine.
You may live your whole life and never visit these places, but these places will affect your life nonetheless.
You know this place. The Moon. Earth’s closest neighbor is little more than a beautiful stranger across an airless room. There are mysteries here and answers. And, like love, perhaps, destiny.
Back on Earth, day and night change like moods, with points of light pricking the darkness like vaguely remembered dreams. City lights shine into space at night, like ancient campfires, like candles of civilization.
No other place beyond the Earth shows signs of life like this, or shows signs of life at all. But we’re looking.
Before we can find life elsewhere, we need to be good at reading its signs at home first. And on Earth, life is everywhere.
This is the living Earth: the biosphere. Phytoplankton bloom in vast oceanic fields. Land plants pulse rhythmically with seasonal growth. Together, these sound the global heartbeat, the pulse of life powered by the sun.
The Sun. All energy on Earth comes from the sun.
The Moon…the Earth…the Sun: celestial spheres we see and feel everyday. But in our solar neighborhood, there are other places, too. Fabulous places. Mysterious places.
As a tourist destination, Mars has an impressive brochure. The longest, deepest canyon in the solar system. A volcano so high it’s peak climbs above most of the Martian atmosphere. Nothing like these places exists on Earth. Nothing.
This is from a NASA mission called WMAP. If the whole universe were a person, this would be its first baby picture. There are no stars here, no galaxies, certainly no planets. But there is energy. The rest came soon enough, once the new kid could collect herself.
This is the universe we see today. It’s a lively place. That’s a gamma ray burst, spotted by NASA’s “SWIFT” satellite. These cosmic blasts have long puzzled scientists. They may be stars collapsing in upon themselves, or two densely packed remnants of stars merging together.
But in either case, scientists believe they herald the births of black holes. They’re the most powerful explosions in the universe after the Big Bang. And they seem to happen all the time, as often as once a day.
We look outwards as much as we look inwards, for if there is any certainty in the journey of knowledge it’s that travel in any direction can lead to the same destination.
We see only what we look for, and in space and on Earth we seek the wisdom to ask the right questions.
When Worlds Collide
Uploaded on Jun 16, 2010
Nearly 60 years ago, audiences thrilled to the destruction of the Earth in George Pal’s classic film, “When Worlds Collide.” The idea of a planetary smash-up is a staple of science fiction, but can it really happen?
Astronomers using NASA’s Spitzer Space Telescope think they’ve actually seen the aftermath of such a collision around another star.
The story unfolded as Dr. Casey Lisse and his team studied disks around young stars. Once planets have formed astronomers think there are a lot of left-over asteroids in the system. They occasionally slam together and produce dusty debris.
Spitzer’s Infrared Spectrograph was designed to detect the faint glow from this material. By spreading the light out into its component colors, astronomers can look for the spectral fingerprints of different minerals.
Our dusty star of interest is a faint speck known as HD 172555. It’s about 100 light years away and 12 million years old which, compared to our 4.5 billion year old Sun, is like a baby born a few days ago.
Studying its spectrum, Dr. Lisse and his colleagues realized they had found something very peculiar that they had not seen around other stars. Aside from the usual indicators of rocky rubble, they found features corresponding to tektite, obsidian, and silicon monoxide gas.
What’s strange is that tektite and obsidian are formed from molten materials. Tektites are hardened chunks of lava found around meteor impacts on Earth, and obsidian is volcanic glass. Vaporized rocks can form silicon monoxide gas.
You don’t get this kind of material by just smashing a couple of asteroids together. The evidence suggests something much more… cataclysmic. Imagine what would happen if our moon slammed, at high velocity, into a Mercury-sized planet. The resulting impact would eject a massive amount of molten material into space. As it cooled it would likely form tektite, obsidian, and silicon monoxide gas, explaining the features seen in the HD 172555 spectrum.
It’s amazing to think Spitzer may have caught the aftermath of such an incredible collision. But, it’s not the first time astronomers have speculated about world-shattering events. In fact, similar things may have happened right here in our own back yard.
Mercury is a strangely dense planet compared to the other worlds in the solar system. Now if it formed from the same stuff as Venus and Earth, why would it be any different? A world-shattering impact could be the answer. When planets form the lighter materials rise and denser ones sink to the core. Remove the outer, lighter layers and you’re left with a denser planet, once what’s left cools off.
Looking to our neighbor Mars we see a massive impact scar in its Southern hemisphere. This area, known as the Hellas Basin, must have formed from an asteroid impact long ago. The resulting plume of molten material would have been blasted into space, some of it eventually reaching the ancient Earth.
Even closer to home, most astronomers believe that our own moon was formed in a similar cataclysm. The theory is that a Mars-sized body grazed the still- forming Earth, generating a massive amount of molten debris. The orbiting rubble would clump together over time, forming the moon.
The tektite and obsidian debris from such massive impacts would not last long around our sun, or others. Solar winds and gravitational interactions tend to sweep away the dust over time, and in a few tens of thousands of years the evidence would be erased.
In the long history of our solar system, that’s hardly the blink of any eye. The evidence may be long gone here, but seeing what may happen when worlds collide around a nearby star shows us it’s not just science fiction after all.
A Super Jupiter Makes its Mark
Uploaded on Jun 10, 2010
This ESOCast video shows how astronomers, for the first time, were able to directly follow the motion of an exoplanet as it moved from one side of its host star to the other. The planet has the smallest orbit so far of all directly imaged exoplanets, lying almost as close to its parent star as Saturn is to the Sun. Scientists believe that it may have formed in a similar way to the giant planets in the Solar System. Because the star is so young, this discovery proves that gas giant planets can form within discs in only a few million years, a short time in cosmic terms.
Only 12 million years old, or less than three-thousandths of the age of the Sun, Beta Pictoris is 75% more massive than our parent star. It is located about 60 light-years away towards the constellation of Pictor (the Painter) and is one of the best-known examples of a star surrounded by a dusty debris disc .
Earlier observations showed a warp of the disc, a secondary inclined disc and comets falling onto the star. “Those were indirect, but tell-tale signs that strongly suggested the presence of a massive planet, and our new observations now definitively prove this,” says team leader Anne-Marie Lagrange. “Because the star is so young, our results prove that giant planets can form in discs in time-spans as short as a few million years.” Recent observations have shown that discs around young stars disperse within a few million years, and that giant planet formation must occur faster than previously thought. Beta Pictoris is now clear proof that this is indeed possible.
The team used the NAOS-CONICA instrument (or NACO ), mounted on one of the 8.2-meter Unit Telescopes of ESO’s Very Large Telescope (VLT), to study the immediate surroundings of Beta Pictoris in 2003, 2008 and 2009. In 2003 a faint source inside the disc was seen (eso0842), but it was not possible to exclude the remote possibility that it was a background star. In new images taken in 2008 and spring 2009 the source had disappeared!
The most recent observations, taken during autumn 2009, revealed the object on the other side of the disc after a period of hiding either behind or in front of the star (in which case it is hidden in the glare of the star). This confirmed that the source indeed was an exoplanet and that it was orbiting its host star. It also provided insights into the size of its orbit around the star.
The planet has a mass of about nine Jupiter masses and the right mass and location to explain the observed warp in the inner parts of the disc. “Together with the planets found around the young, massive stars Fomalhaut and HR8799, the existence of Beta Pictoris b suggests that super-Jupiters could be frequent byproducts of planet formation around more massive stars,” explains Gael Chauvin, a member of the team.
The Eerie Sounds Of Saturn
Uploaded on May 10, 2010
The Cassini spacecraft has been detecting intense radio emissions from the planet Saturn. They come from the planet’s aurorae, where magnetic field lines thread the polar regions. These signals have been shifted into the range of human hearing and compressed in time. For more information about how NASA produced this track, go to…
Pluto Red Outpost on the Final Frontier
Uploaded on May 5, 2010
Pluto was kicked off the list of major planets. It seems to have responded by turning a mysterious red color, according to scientists working with the Hubble Space Telescope. They’re now trying to find out what makes its surface so dynamic. From the Space Telescope Science Institute.
Hubble Space-Shattering Discoveries
Uploaded on Apr 28, 2010
Tribute to the Hubble Space Telescope on its 20th anniversary in space. This beautiful video surveys the incredible accomplishments of this revolutionary instrument: everybody’s favorite telescope.
Saturn Struck By Lightning
Uploaded on Apr 21, 2010
Saturn Cassini mission team members from NASA’s Jet Propulsion Lab recount their observations of lightning bolts flashing in the outer regions of Saturn’s atmosphere.
Fly Down into the Marianas Trench
Uploaded on Mar 25, 2010
This is a flight down into a data visualization of the undersea mountains and trenches of the Pacific Ocean, ending up in the deepest part of the ocean, the Marianas Trench. The “Challenger Deep” is measured at 35,813 feet below the surface, or 10,915 meters. Courtesy of NOAA’s Marine Geology and Geophysics Division.
How to Wrangle a Giant Telescope Mirror
Uploaded on Mar 19, 2010
Fascinating account of how technicians remove a giant telescope mirror at the Very Large Telescope Array in Chile and then clean and refinish it.
Mars Strange Volcano and Impact Features
Uploaded on Mar 4, 2010
Strange and beautiful are these new images from the HIRISE camera aboard the Mars Reconnaissance Orbiter. Courtesy NASA/JPL/University of Arizona.
Earth 100 Million Years From Now
Uploaded on Feb 12, 2010
Earth’s landmasses were not always what they are today. Continents formed as Earth’s crustal plates shifted and collided over long periods of time. This video shows how today’s continents are thought to have evolved over the last 600 million years, and where they’ll end up in the next 100 million years. Paleogeographic Views of Earth’s History provided by Ron Blakey, Professor of Geology, Northern Arizona University.
Milky Way Hot and Cold
Uploaded on Feb 10, 2010
ESA’s new Herschel Space Observatory and NASA’s Spitzer Space Telescope combine to show the Milky Way at its coldest and hottest. From NASA/JPL/Caltech’s Hidden Universe series.
Orion Nebula, Buried Secrets
Uploaded on Feb 10, 2010
New infrared images of the fabled Orion Nebula, from the penetrating gaze of ESO’s new Vista Telescope. From ESOCast, staring the famous Dr. J.
Cosmic Journeys : Voyage to Pandora: First Interstellar Space Flight
Uploaded on Feb 8, 2010
Pandora is the idyllic blue world featured in the movie Avatar. Its location is a real place: Alpha Centauri, the nearest star to our Sun and the most likely destination for our first journey beyond the solar system.
Remarkably, it’s anti-matter, the science fiction fuel of choice that could take us there. Normally, it’s only created in powerful jets that roar out of black holes. We can now produce small quantities in Earth-bound particle colliders. Will we journey out only to plunder other worlds? Or will we come in peace? The answer may depend on how we see Earth at that time in the distant future.
The year is 2154. Our planet has been ruined by environmental catastrophe. In the movie Avatar, greedy prospectors from Earth descend on the world of an innocent hunter-gatherer people called the Na’vi.
Their home is a lush moon far beyond our solar system called Pandora. Could such a place exist? And could our technology… and our appetite for exploration… one day send us hurtling out to reach it?
In fact, the supposed site of this fictional solar system is one of our most likely interstellar targets, until a better destination turns up. Pandora orbits a fictional gas planet called Polyphemus. Its home is a real place… Alpha Centauri… the brightest star in the southern constellation of Centaurus.
At 4.37 light years away, it’s part of the closest star system to our sun. Alpha Centauri is actually two stars, A and B, one slightly larger and more luminous than our own sun, the other slightly smaller.
The two stars orbit one other, swinging in as close as Saturn is to our Sun… then back out to the distance of Pluto. This means that any outer planets in this system… anything beyond, say, the orbit of Mars… would likely have been pulled away by the companion and flung out into space.
For this reason, Alpha Centauri was not high on planet hunters’ lists… until they began studying a star 45 light years away called “Gamma Cephei.” It has a small companion star that goes around it every 76 years. Now, it seems… it also has at least one planet.
That world is about the size of Jupiter, and it has planet hunters excited. Perhaps two-thirds of all the stars in our galaxy are in so-called binary relationships. That means there could be many more planets in our galaxy that astronomers once assumed.
At least three teams are now conducting long-term studies of Alpha Centauri… searching for slight wobbles in the light of each companion star that could indicate the presence of planets. If they find a planet that passes in front of one of the stars, astronomers will begin intensive studies to find out what it’s like.
One of their most promising tools will be the James Webb Space Telescope, scheduled for launch in 2014 or 2015. From a position a million miles away from Earth, it will deploy a sun shield the size of a tennis court, and a mirror over 21 feet wide. The largest space telescope ever built, it will offer an extraordinary new window into potential solar systems like Alpha Centauri.
With its infrared light detectors, this telescope will be able to discern the chemical composition of a planet’s atmosphere… and perhaps whether it harbors a moon like Pandora.
One prominent planet hunter predicted that if a habitable world is found at Alpha Centauri, the planning for a space mission would begin immediately. Here’s that star duo as seen by the Cassini spacecraft just above the rings of Saturn.
To actually get to this pair of stairs, you have to travel as far as the orbit of Saturn, then go another 30,000 times further. Put another way, if the distance to Alpha Centauri is the equivalent of New York to Chicago, then Saturn would be just… one meter away.
So far, the immense distances of space have not stopped us from launching missions into deep space. In 1977, the twin Voyager spacecraft were each sent on their way aboard Titan 3 Centaur rockets. After a series of gravitational assists from the giant outer planets, the spacecraft are now flying out of the solar system at about 40,000 miles per hour.
They are moving so quickly that they could whip around the Earth in just 45 minutes, twice as fast as the International Space Station. Voyager I has now traveled over 110 astronomical units. That’s 110 times the distance from Earth to the Sun… or about 10 billion miles. But don’t hold your breath.
If it was headed in the right direction, it would need another 73,000 years to travel the 273,000 astronomical units to Alpha Centauri. When it comes to space travel, we’ve yet to realize the dream forged by rocketeers a century ago.
Jupiter: the Largest
Uploaded on Jan 29, 2010
This video is an adaptation of the breezy Science on a Sphere production by supremely talented members of NASA’s Scientific Visualization Studio. This video explores Jupiter’s role as the 800 pound gorilla of our solar system, with stops on its fascinating moons and the big red spot. Additional video from NASA JPL and ESA Hubble.
The Beauty Of Stars Being Born
Uploaded on Jan 20, 2010
Hubblecast explores new Hubble Space Telescope images of star birth in the Orion Nebula, and animations illustrating how it happens. ESA Hubble, with the famous Dr. J.
Cosmic Journeys : The Search For Earth-Like Planets
Uploaded on Jan 8, 2010
The search for Earth-like planets is reaching a fever-pitch. Does the evidence so far help shed light on the ancient question: Is the galaxy filled with life, or is Earth just a beautiful, lonely aberration? If things dont work out on this planet Or if our itch to explore becomes unbearable at some point in the future Astronomers have recently found out what kind of galactic real estate might be available to us. Well have to develop advanced transport to land there, 20 light years away. The question right now: is it worth the trip?
If things don’t work out on this planet…
Or if our itch to explore becomes unbearable at some point in the future…
Astronomers have recently found out what kind of galactic real estate might be available to us.
We’ll have to develop advanced transport to land there, 20 light years away…. But that’s for later.
The question right now: is it worth the trip? The destination is a star that you can’t see with your naked eye, in the southern constellation Libra, called Gliese 581.
Identified over 40 years ago by the German astronomer Wilhelm Gliese, it’s a red dwarf with 31% of the Sun’s mass… and only 1.3% of its luminosity.
Until recently, the so-called M Stars like Gliese 581 flew below the radar of planet hunters.
They give off so little energy that a planet would have to orbit dangerously close just to get enough heat.
Now, these unlikely realms are beginning to show some promise… as their dim light yields to precision technologies…
…as well as supercomputers… honed in the battle to understand global changes on this planet… Earth.
Will we now begin to detect signs of alien life?
Or will these worlds, and the galaxy itself, turn out to be lifeless… and Earth, just a beautiful, lonely aberration?
To some, like astronomer and author Carl Sagan, the sheer number and diversity of stars makes it, as he said, “far more likely that the universe is brimming over with life.”
This so-called “many worlds” view can be traced back to ancient observers… in China, India, Greece and Egypt. The Qur’an, the Talmud, and many Hindu texts all imagined a universe full of living beings.
In the 16th Century, this view got a boost from astronomer and mathematician Nikolas Copernicus… who came to believe that Earth is not the center of the universe, but revolves around the Sun.
Seven decades after Copernicus, Galileo Galilei used his newly developed telescope to show that our Sun was just one among countless other stars in the universe.
By the modern era, the “many worlds” view held sway in scientific circles. A variety of thinkers considered what and who inhabited worlds beyond our own.
From Martians desperate to get off their planet… to alien invaders intent on launching pre-emptive strikes against ours… or simple life forms on an evolutionary track to complexity.
But other thinkers have been struck by a different view.
The Greek philosophers Aristotle and Ptolemy believed that humans and Earth are unique.
With the spread of Christianity, this Ptolemaic system became widely accepted.
The latest variation on this theme is what’s called the “Rare Earth” hypothesis. It holds that Earth and sophisticated life were the result of fortuitous circumstances that may not be easy to find again in our galaxy.
Does the current search for planets shed light on this debate… sending it in one direction or the other?
So far, our only good reference for recognizing an Earth-like planet is… Earth.
It does have some fortuitous characteristics… it’s dense, it’s rocky — with a complex make-up of minerals and organic compounds — and it has lots and lots of water.
It’s also got a nearly circular orbit around the Sun, at a distance that allows liquid water to flow… not too close and not too far away, in the so-called “Habitable Zone.”
That’s defined as the range of distance from a parent star that a planet would need to maintain surface temperatures between the freezing and boiling points of water.
Of course, that depends on the size of the planet, the make-up of its atmosphere, and a host of other factors.
And whether the parent star is large; medium like the Sun; or small.
Some scientists also believe we live in a “Galactic Habitable Zone.” We’re close enough to the galactic center to be infused with heavy elements generated by countless stellar explosions over the eons…
But far enough away from deadly gamma radiation that roars out of the center.
If there is a galactic habitable zone… it’s thought to lie 26,000 light years from the center… about where we are… give or take about 6,000 light years.
Supermassive Black Hole in the Milky Way Galaxy
Uploaded on Dec 9, 2009
From a distance, our galaxy would look like a flat spiral, some 100,000 light years across, with pockets of gas, clouds of dust, and about 400 billion stars rotating around the galaxys center. Thick dust and blinding starlight have long obscured our vision into the mysterious inner regions of the galactic center. And yet, the clues have been piling up, that something important, something strange is going on in there. Astronomers tracking stars in the center of the galaxy have found the best proof to date that black holes exist. Now, they are shooting for the first direct image of a black hole.
From a distance, our galaxy would look something like this.
A flat spiral, some 100,000 light years across, with pockets of gas, clouds of dust, and about 400 billion stars rotating around the galaxy’s center.
That center — bulging up and out of the galactic disk — is tightly packed with stars.
Thick dust and blinding starlight have long obscured our vision into the mysterious inner regions of this so-called “bulge.”
And yet, the clues have been piling up, that something important…something strange… is going on in there.
The first to take notice was the physicist Karl Jansky back in the 1930s.
He was asked by his employer, Bell Telephone Labs, to investigate sources of static that might interfere with what it saw as the killer app of its time… radio voice transmissions.
Using this ungainly radio receiver… Jansky methodically scanned the airwaves. He documented thunderstorms, near and far… and another signal he could not explain.
It sounded like steam — a hiss of radio noise. Jansky narrowed it to a spot in the constellation of Sagittarius, in the direction of the center of the galaxy.
Located within a larger pattern of radio emissions… … Jansky’s sighting would become known as Sagittarius A*.
The word of Jansky’s finding got out. He assured the public that it was not aliens seeking contact.
But that’s just about all anyone could say… for over three decades.
Then Erik Becklin got on the case.
Becklin is one of those rare researchers whose curiosity and determination push our understanding to a whole new level.
It was the 1960’s and astronomy, like society, was in a period of ferment. Startling new observations were being made… and new interpretations were in the air.
Quasars had just been discovered… extremely bright beacons of light from deep space. Were they coming from the centers of distant galaxies? And what powerful objects were generating them?
To study an event at the center of a galaxy, you have locate it. Young Becklin first took aim at our neighboring galaxy, Andromeda.
In ultraviolet light, you can see a dense glow in the middle. Becklin found the point where the light reaches peak intensity… and marked it as the Center.
From our orientation in space, all of the Andromeda galaxy is in full view.
But our galaxy is a different story. We live inside it, of course. Becklin had to find a way to see through all the dust and gas that obscure our line of sight into the center. So he went to a military contractor…
…and obtained a device that reads infrared light… whose wavelengths are similar to the distances between particles in a dust cloud, allowing them to move right through.
Becklin began measuring the brightness of the light as it rose to a peak… marking the location of the galactic center.
Pinpointing this site would now allow astronomers to begin probing for details with a new generation of powerful telescopes… to peer into the bright lights… the forbidden zones… deep in the heart of the Milky Way.
Becklin wasn’t the only astronomer interested in the galactic center.
Reinhardt Genzel, and a team based at the Max Planck Institute for Extraterrestrial Physics in Germany, began a similar campaign in 1990… from the New Technology Telescope in the mountains of Chile.
A few years later, in 1993, high atop Hawaii’s Mauna Kea volcano…
Eric Becklin and colleagues, including Andrea Ghez, began using the newly christened Keck Telescope. The American and German groups shared the same goal… to pinpoint the precise location of Sagittarius A*, and find out what it is.
Because the object is too small to see… at 26,000 light years away… they would study it by tracking the orbits of stars around it.
Even seeing them would take the sensitivity of Keck’s wide aperture; an instrument powerful enough to detect a single candle flame at the distance of the moon…
Meanwhile, using a similar technique, astronomers had focused the new Hubble Space Telescope on a different galaxy… a giant elliptical cloud of nearly a billion stars, lying some 50 million light years away called M87.
Saturn’s Beautiful Aurora
Uploaded on Nov 25, 2009
Beautiful space weather on Saturn, from the Cassini spacecraft. From NASA/JPL.
Apollo 12 on the Ocean of Storms
Uploaded on Nov 18, 2009
Ultra high-resolution photos of this historic second manned mission to the moon, including breathtaking photos of the lunar surface. Credit NASA.
When Will Time End? (Version 1)
Uploaded on Nov 10, 2009
It now seems that our entire universe is living on borrowed time. How long it can survive depends on whether Stephen Hawking’s theory checks out. Special thanks to Ivan Bridgewater for use of footage.
Time is flying by on this busy, crowded planet… as life changes and evolves from second to second.
And yet the arc of human lifespan is getting longer: 65 years is the global average … way up from just 20 in the Stone Age.
Modern science, however, provides a humbling perspective. Our lives… indeed the life span of the human species… is just a blip compared to the age of the universe, at 13.7 billion years and counting.
It now seems that our entire universe is living on borrowed time…
And that even it may be just a blip within the grand sweep of deep time.
Scholars debate whether time is a property of the universe… or a human invention.
What’s certain is that we use the ticking of all kinds of clocks… from the decay of radioactive elements to the oscillation of light beams… to chart and measure a changing universe… to understand how it works and what drives it.
Our own major reference for the passage of time is the 24-hour day… the time it takes the Earth to rotate once. Well, it’s actually 23 hours, 56 minutes and 4.1 seconds… approximately… if you’re judging by the stars, not the sun.
Earth acquired its spin during its birth, from the bombardment of rocks and dust that formed it.
But it’s gradually losing that rotation to drag from the moon’s gravity.
That’s why, in the time of the dinosaurs, a year was 370 days… and why we have to add a leap second to our clocks about every 18 months.
In a few hundred million years, we’ll gain a whole hour.
The day-night cycle is so reliable that it has come to regulate our internal chemistry.
The fading rays of the sun, picked up by the retinas in our eyes, set our so-called “circadian rhythms” in motion.
That’s when our brains begin to secrete melatonin, a hormone that tells our bodies to get ready for sleep. Long ago, this may have been an adaptation to keep us quiet and clear of night-time predators.
Finally, in the light of morning, the flow of melatonin stops. Our blood pressure spikes… body temperature and heart rate rise as we move out into the world.
Over the days … and years… we march to the beat of our biology.
But with our minds, we have learned to follow time’s trail out to longer and longer intervals.
Philosophers have wondered… does time move like an arrow… with all the phenomena in nature pushing toward an inevitable end?
Or perhaps, it moves in cycles that endlessly repeat… and even perhaps restore what is there?
We know from precise measurements that the Earth goes around the sun once every 365.256366 days.
As the Earth orbits, with each hemisphere tilting toward and away from its parent star, the seasons bring on cycles of life… birth and reproduction… decay and death.
Only about one billionth of the Sun’s energy actually hits the Earth. And much of that gets absorbed by dust and water vapor in the upper atmosphere.
What does make it down to the surface sets many planetary processes in motion.
You can see it in the annual melting and refreezing of ice at the poles… the ebb and flow of heat in the tropical oceans…
The seasonal cycles of chlorophyll production in plants on land and at sea… and in the biosphere at large.
These cycles are embedded in still longer Earth cycles.
Ocean currents, for example, are thought to make complete cycles ranging from four to around sixteen centuries.
Moving out in time, as the Earth rotates on its axis, it completes a series of interlocking wobbles called Milankovic cycles every 23 to 41,000 years.
They have been blamed for the onset of ice ages about every one hundred thousand years.
Then there’s the carbon cycle. It begins with rainfall over the oceans and coastal waves that pull carbon dioxide into the sea.
New Discovery about the Fabric of Space-Time
Uploaded on Nov 7, 2009
Scientists have turned up rare evidence that space-time is smooth as Einstein predicted, while pushing closer to a complete theory of gravity. From NASA Goddard Space Flight Center, Fermi Gamma Ray Space Telescope.
How Large is the Universe? (VERSION 1)
Uploaded on Oct 19, 2009
The universe has long captivated us with its immense scales of distance and time.
How far does it stretch? Where does it end… and what lies beyond its star fields… and streams of galaxies extending as far as telescopes can see?
These questions are beginning to yield to a series of extraordinary new lines of investigation… and technologies that are letting us to peer into the most distant realms of the cosmos…
But also at the behavior of matter and energy on the smallest of scales.
Remarkably, our growing understanding of this kingdom of the ultra-tiny, inside the nuclei of atoms, permits us to glimpse the largest vistas of space and time.
In ancient times, most observers saw the stars as a sphere surrounding the earth, often the home of deities.
The Greeks were the first to see celestial events as phenomena, subject to human investigation… rather than the fickle whims of the Gods.
One sky-watcher, for example, suggested that meteors are made of materials found on Earth… and might have even come from the Earth.
Those early astronomers built the foundations of modern science. But they would be shocked to see the discoveries made by their counterparts today.
The stars and planets that once harbored the gods are now seen as infinitesimal parts of a vast scaffolding of matter and energy extending far out into space.
Just how far… began to emerge in the 1920s.
Working at the huge new 100-inch Hooker Telescope on California’s Mt. Wilson,
astronomer Edwin Hubble, along with his assistant named Milt Humason, analyzed the light of fuzzy patches of sky… known then as nebulae.
They showed that these were actually distant galaxies far beyond our own.
Hubble and Humason discovered that most of them are moving away from us. The farther out they looked, the faster they were receding.
This fact, now known as Hubble’s law, suggests that there must have been a time when the matter in all these galaxies was together in one place.
That time… when our universe sprung forth… has come to be called the Big Bang.
How large the cosmos has gotten since then depends on how long its been growing… and its expansion rate.
Recent precision measurements gathered by the Hubble space telescope and other instruments have brought a consensus…
That the universe dates back 13.7 billion years.
Its radius, then, is the distance a beam of light would have traveled in that time … 13.7 billion light years.
That works out to about 1.3 quadrillion kilometers.
In fact, it’s even bigger…. Much bigger. How it got so large, so fast, was until recently a deep mystery.
That the universe could expand had been predicted back in 1917 by Albert Einstein, except that Einstein himself didn’t believe it…
until he saw Hubble and Humason’s evidence.
Einstein’s general theory of relativity suggested that galaxies could be moving apart because space itself is expanding.
So when a photon gets blasted out from a distant star, it moves through a cosmic landscape that is getting larger and larger, increasing the distance it must travel to reach us.
In 1995, the orbiting telescope named for Edwin Hubble began to take the measure of the universe… by looking for the most distant galaxies it could see.
Taking the expansion of the universe into account, the space telescope found galaxies that are now almost 46 billion light years away from us in each direction… and almost 92 billion light years from each other.
And that would be the whole universe… according to a straightforward model of the big bang.
But remarkably, that might be a mere speck within the universe as a whole, according to a dramatic new theory that describes the origins of the cosmos.
It’s based on the discovery that energy is constantly welling up from the vacuum of space in the form of particles of opposite charge… matter and anti-matter.
Hubble Dazzling First Light Images in HD
Uploaded on Sep 9, 2009
Spectacular new images from distant space that you must see to believe. The revolutionary Hubble Space Telescope will continue to open our eyes to the universe.
Proof that Black Holes Exist
Uploaded on Sep 3, 2009
Ride this 26,000 light year zoom into the heart of the MW. The speeds and orbits of stars were used to calculate the mass of the central object, a black hole of 4 million solar masses.
The Asteroid that Flattened Mars
Uploaded on Aug 20, 2009
Just about every two years, the planet Mars makes its closest approach to Earth… around 36 million miles.
That’s when we pack our robotic emissaries off to the Red Planet, timing their launches to spend the least effort to get there.
Some fly around it… snapping pictures…
Others land … to sample its surface….
…a few to crawl around its canyons and craters.
These probes may pave the way for human explorers… and, perhaps permanent settlers… who’ll dig deeper still… in search of answers to our most pressing question:
Did Mars develop far enough — and stay that way long enough — for life to arise?
And, if so, does anything live now within Mars’ dusty plains… beneath its ice caps… or maybe somewhere underground?
Mars does not give up its secrets easily … it’s almost as if the little planet is embarrassed.
Over a century ago, a few observers thought they saw clues that Mars is alive.
In 1877, the Italian astronomer Giovanni Schiaparelli noted markings… which he saw as a latticework of lines. He called them “canali” in Italian… meaning nothing more than “shallow channels” in English.
American astronomer, Percival Lowell, found the lure of these features irresistible.
He saw Schiaparelli’s channels as artificial canals. He speculated that they carried melting snow from the poles to the dry interior.
After all, on Earth, the Suez Canal had recently opened to ship traffic. The Panama Canal was beginning to be dug.
The Martian canals, Lowell said, were built by a sophisticated society confronting an environmental catastrophe on the grandest of scales.
Those Martians, he thought, must face urgent choice: move water across vast arid regions, or perish on an increasingly dry planet.
As the 19th Century gave way to the 20th, Lowell took his case to the public, in a series of three best-selling books.
And the public responded with… questions.
Who were these Martians, who had the means to remake an entire planet?
Some offered schemes for making contact. Giant mirrors would flash greetings… Light beams… Mental telepathy.
Many astronomers grew deeply skeptical… but Lowell’s vision of a harsh, yet Earth-like planet endured in the public’s imagination..
That vision was dealt harsh blow in 1964. The Mariner Four spacecraft ventured in for a closer look… And what it saw looked like the Moon.
Three more Mariners followed.
They found huge dormant volcanoes… the deepest and longest canyon in the solar system…but not a trace of life, present or past.
In the mid-1970’s, two lander-orbiter robot teams, named Viking, took up residence at Mars.
Maybe the Martians were just hiding, so theVikings tested the soil for signs of life.
But all the evidence from Viking told us… Mars is not only barren… but in fact hostile to life.
It’s no wonder. Martian air temperatures range from –20 degrees Fahrenheit to down below –200.
It’s also very, very dry. The Sahara Desert on Earth is a rainforest, by comparison. If all of the water vapor in Mars’ thin atmosphere fell as snow, it would make a layer of frost not thicker than your fingernail.
On Earth, impact craters erode over time from wind and water… and even volcanic activity.
On Mars, they can linger for billions of years.
But so can the imprint of riverbeds, lake bottoms and ocean shorelines… And the Viking orbiters saw a lot of them.
It’s not hard to believe that a great deal of water once flowed here.
But where did all the water go?
To find out, scientists needed to do real field-geology on Mars. They needed rovers… travelling robots with tools and instruments.
Saturn’s Mysterious Moons (V1)
Uploaded on Aug 12, 2009
Make sure you see version 2 of this video. Some 900 million miles from the Sun,orbiting the planet Saturn, lies a mysterious world. Enceladus is enveloped in ice. Because nearly all of the sunlight that manages to hit its surface is reflected back into space, it’s one of the brightest objects in the solar system.
At its equator, the temperature is –315 degrees Fahrenheit. But, at the poles, the temperature is at least 15 degrees warmer… and as much as 65 degrees warmer in grooves that stretch across the south like tiger stripes.
In 2005, the Cassini spacecraft spotted a complex plume of water vapor shooting out into space from several locations near the south pole. That may mean that Enceladus harbors a remarkable secret below its frigid surface:
A liquid ocean… and maybe… some forms of life. This discovery was the culmination of a search that began over three decades ago. Back in 1979, the outer planets of the solar system lined up in such a way that mission planners were able to dispatch the Voyager spacecraft to fly past each of them.
The two Voyagers sent back tens of thousands of images… of planetary realms more diverse than anyone had imagined. These long-distance marathon flyers – both now headed out towards interstellar space – made discoveries about the planetary chemistry that make these gas giants appear to us as gigantic works of abstract art.
The Voyagers disclosed new details about their magnetic fields, atmospheres, ring systems, and even the nature of their inner cores. Voyager turned up some surprising new mysteries too: a huge dark spot — a storm in fact – on Neptune. They found that Uranus is tipped 90 degrees to one side. That Saturn is less dense than water; if you had a bathtub big enough, Saturn would float!
And that you’d need the mass of three Saturns to make just one Jupiter! But what really knocked the scientists’ socks off were the moons that orbit these gas giants. All of them have been pummeled over the millennia by wayward asteroids and comets.
But a few appear to also be sculpted by forces below their icy surfaces. Neptune’s largest moon Triton has few craters. It’s marked with circular depressions bounded by rugged ridges that may mean the icy surface is collapsing. There are also grooves and folds in the land that stretch for dozens of miles, a sign of fracturing and deforming.
Triton has geysers too. But these are not spurts of water. On frigid Triton — so far from the Sun — the liquid that spouts some five miles above the planet is nitrogen. No one yet knows exactly what drives them. Tiny Miranda… one of 27 known moons that orbit Uranus… wears a jumbled skin that’s been shaped and reshaped. Most likely, its outer crust is slipping and sliding on a molten core.
The moon called Io — orbiting perilously close to giant Jupiter is literally turning itself inside out! Rivers of sulfurous lava roll down from open craters that are constantly erupting. What was causing these tiny moons to generate so much energy from within? The answer may well be here… on Jupiter’s Europa — just slightly smaller than Earth’s Moon.
Voyager saw no signs of volcanic activity, but –but instead documented a complex network of criss-crossing grooves and ridges. In the 1990s, the Galileo spacecraft was sent back to get a closer look at Europa and its sister moons. .
It found that Europa’s surface is a crazy quilt of fractured plates, cliff faces and gullies… amid long grooves like a network of superhighways. How did it get like this?
Well, as it orbits around Jupiter in a nearly circular ellipse, the massive planet’s gravity constantly tugs at Europa’s rocky core. The friction of rock rubbing on rock causes that core to heat up. That heat rises up through an ocean of liquid water… then cracks and spreads the icy surface in a thousand different ways.
Callisto and Ganymede also show such features… suggesting they have — or perhaps once had –liquid oceans below their surfaces too! Crossing outward to the Saturn system, Voyager’s images from the late 1970’s showed that the moon Enceladus had a similar surface…
The same was presumed of Saturn’s by far largest moon, Titan… enshrouded in heavy clouds. So when the Cassini spacecraft arrived in 2004 to scrutinize the kingdom of Saturn, it came ready to answer a range of burning questions.
Can such moons really have liquid oceans beneath their surfaces… and do those oceans have the ability to cook up and then support life?
How Black Holes Erupt
Uploaded on Jul 29, 2009
Just as matter begins to swirl into a black hole, magnetic fields hurl it out in powerful jets.
Apollo 11 on the Sea of Tranquility
Uploaded on Jul 12, 2009
Breathtaking ultra high resolution photos of mankind’s historic first steps on the Moon… on the lunar Sea of Tranquility. Monday July 20th is the 40th anniversary of this first moonwalk. Music is Chopin’s Trois Nouvelles Etudes, 2nd in A flat major.
Uploaded on Jun 30, 2009
Ripples in the fabric of space-time from monumental collisions between black holes, and how scientists are trying to measure them with lasers and mirrors. From LIGO and the National Science Foundation.
Probing the Secrets of Matter and Energy
Uploaded on Jun 28, 2009
How ultra-sophisticated technology is designed to probe deeper questions about the nature of matter and energy. From the Large Hadron Collider at Cern.
Blast into Space, Spectacular Fall to Earth
Uploaded on May 28, 2009
Onboard cameras capture the amazing journey of Atlantis into space, and the dramatic return of the solid rocket boosters.
Secrets of a Dynamic Sun
Uploaded on Apr 27, 2009
Five major recent discoveries about our Sun. From NASA’s Goddard Space Flight Center.
The Pulse of Alien Life
Uploaded on Jan 11, 2009
To find other life in our solar system, we may have to prospect for it. Our destinations: Mars and Europa, one of Jupiters moons. Beneath Europa’s crust, scientists believe, is an ocean of volcanically heated mud — just the kind of environment that can spawn primitive microbes. The turbulence churning below is written across a veneer of ice. Europas surface is rent with fractures. The spacecraft Galileo recently sent back images of a zone, bulging with spill-over from the moon’s roiling interior. If life exists here, then who can doubt it also has emerged in the universe beyond?
Search for Alien Worlds
Uploaded on Jan 11, 2009
They are strangers to us. Long as our world has lived among them, the stars have offered scant overtures, save their faint flickers across the void. They are messengers of a universe that seems utterly barren of other life. And yet, there is reason to believe our galaxy teems with planets.
Uploaded on Jan 3, 2009
To some there is no vision more reassuring: the cycles of the sun and the moon, the heavens ceaselessly turning. The night sky is unchanging and eternal — Or so it seems. But modern astronomy has given us a much different vision: a universe that roils and vents its rage… In fierce radiation jets that erupt from newborn stars. In netherworlds where matter billions of times the mass of our sun collapses to a single point. In the most violent explosions since the Big Bang… The supernova.
Mysterious Black Holes
Uploaded on Jan 3, 2009
In the fold of our home galaxy, the Eagle Nebula is one of the richest of the great star nurseries. Intense stellar winds have sculpted a majestic castle of gas. Inside these giant columns, stars are being born. Yet for the dying stars that set this process in motion, the consequences are grim. Supernovae leave in their wake a range of bizarre objects. Among them, tiny ultra-dense objects called neutron stars, and their strange, other worldly cousins, black holes.
To the Edge of Space
Uploaded on Jan 2, 2009
The Hubble Space Telescope is probing regions billions of light years away, when the universe was far younger than it is today. There, galaxies have blotchy, distorted shapes. They are pocked with the bright blue signature of myriad stars being born.
To the Edge of Time
Uploaded on Jan 2, 2009
Today, the science of astronomy is being transformed by a new age of technological advances. On mountaintops around the world, scientists are opening ever larger telescopes, capturing light from ever more distant reaches of the universe.
That light may have traveled millions, even billions, of years to reach us. By the time it does, it offers a window into the distant past.
Stunning Portrait of the Milky Way Galaxy
Uploaded on Dec 31, 2008
New image from the Spitzer Space Telescope.
First Image of an Alien Planet
Uploaded on Nov 19, 2008
Hubble Space Telescope does it again, from ESA’s “Hubblecast.”
Vomit Comets and Space Hotels
Uploaded on Oct 8, 2008
We’re now preparing to escape Earth’s gravity and soar into the firmament. What would a vacation in space be like?
Uploaded on Aug 22, 2008
Hubble Space Telescope tracking magnetic energy roaring from the heart of a distant galaxy. From ESA’s “Hubblecast.”
Amazing History of the Telescope
Uploaded on Jul 28, 2008
Early history of the telescope from ESA’s Hubblecast.
What’s Inside a Black Hole?
Uploaded on Jul 11, 2008
Take a ride on the Black Hole Flight Simulator, courtesy of Professor Andrew Hamilton. You can read about this work in this NY Times article… http://www.nytimes.com/2006/02/28/sci…
Laser Pumped Flying Saucer Spacecraft
Uploaded on Jun 22, 2008
The “Lightcraft” is a laser-propelled spacecraft concept that could ultimately run on other beamed energies, such as microwave.
Baseball on the Moon
Uploaded on May 15, 2008
What will it mean to civilization when astronauts begin playing their favorite game on the Moon?
Black Hole Eruption in the Galactic Center
Uploaded on May 14, 2008
Here’s what will happen in about 10 million years when a huge cloud collapses onto a supermassive black hole in the center of the Milky Way galaxy.