Hubble Witnesses an Asteroid Mysteriously Disintegrating
Though fragile comet nuclei have been seen falling apart as they near the Sun, nothing like the slow breakup of an asteroid has ever before been observed in the asteroid belt. A series of Hubble Space Telescope images shows that the fragments are drifting away from each other at a leisurely one mile per hour. This makes it unlikely that the asteroid is disintegrating because of a collision with another asteroid. A plausible explanation is that the asteroid is crumbling due to a subtle effect of sunlight. This causes the rotation rate to slowly increase until centrifugal force pulls the asteroid apart. The asteroid's remnant debris, weighing in at 200,000 tons, will in the future provide a rich source of meteoroids.
Hubble Celebrates Its 24th Anniversary with an Infrared Look at a Nearby Star Factory
This colorful Hubble Space Telescope mosaic of a small portion of the Monkey Head Nebula unveils a collection of carved knots of gas and dust silhouetted against glowing gas. The cloud is sculpted by ultraviolet light eating into the cool hydrogen gas. As the interstellar dust particles are warmed from the radiation from the stars in the center of the nebula, they heat up and begin to glow at infrared wavelengths, as captured by Hubble. The space photo superficially resembles the "The Great Wave" print by 19th century Japanese artist Katsushika Hokusai.
Comet Siding Spring is plunging toward the Sun along a roughly 1-million-year orbit. The comet, discovered in 2013, was within the radius of Jupiter's orbit when the Hubble Space Telescope photographed it on March 11, 2014. Hubble resolves two jets of dust coming from the solid icy nucleus. These persistent jets were first seen in Hubble pictures taken on Oct. 29, 2013. The feature should allow astronomers to measure the direction of the nucleus's pole, and hence, rotation axis. The comet will make its closest approach to our Sun on Oct. 25, 2014, at a distance of 130 million miles, well outside Earth's orbit. On its inbound leg, Comet Siding Spring will pass within 84,000 miles of Mars on Oct. 19, 2014, which is less than half the Moon's distance from Earth. The comet is not expected to become bright enough to be seen by the naked eye.
Hubble Finds That Monster 'El Gordo' Galaxy Cluster Is Bigger Than Thought
If someone told you there was an object in space called "El Gordo" (Spanish for "the fat one") you might imagine some kind of planet-eating monster straight out of a science fiction movie. The nickname refers to a monstrous cluster of galaxies that is being viewed at a time when the universe was just half of its current age of 13.8 billion years. This is an object of superlatives. It contains several hundred galaxies swarming around under a collective gravitational pull. The total mass of the cluster, and refined in new Hubble measurements, is estimated to be as much as 3 million billion stars like our Sun (about 3,000 times more massive than our own Milky Way galaxy) – though most of the mass is hidden away as dark matter. The cluster may be so huge because it is the result of a titanic collision and merger between two separate galaxy clusters. Thankfully, our Milky Way galaxy grew up in an uncluttered backwater region of the universe.
Astronomers using the Hubble Space Telescope have gone looking for water vapor in the atmospheres of three planets orbiting stars similar to the Sun – and have come up nearly dry. The planets spectroscopically surveyed have only one-tenth to one one-thousandth the amount of water predicted by standard planet-formation theories. The planets are not habitable because they are gaseous and are as big as Jupiter. They lie so much closer to their host star than Jupiter is to our Sun, so their atmospheres are seething between 1,500 and 4,000 degrees Fahrenheit. Nevertheless, this result suggests that some percentage of Earth-size exoplanets may be more deficient in water than predicted. And, water is a necessary prerequisite for life as we know it. The search for water-bearing terrestrial worlds may be more challenging than thought for future space telescopes. And, scientists may have to revisit their theories of planet formation.
NASA Telescopes Find Clear Skies and Water Vapor on Exo-Neptune
The weather forecast for a planet 120 light-years from Earth is clear skies and steamy water vapor. Finding clear skies on a gaseous world the size of Neptune is a good sign that even smaller, Earth-size planets might have similarly good visibility. This would allow earthbound astronomers to measure the underlying atmospheric composition of an exoplanet. Astronomers using the Hubble, Spitzer, and Kepler space telescopes were able to determine that the planet, cataloged HAT-P-11b, has water vapor in its atmosphere. The world is definitely steamy with temperatures over 1,000 degrees Fahrenheit. The planet is so hot because it orbits so close to its star, completing one orbit every five days.
Close Encounters: Comet Siding Spring Seen Next to Mars
This is a photo composite of the encounter of Comet Siding Spring with Mars on October 19, 2014. Separate Hubble Space Telescope images of Mars and the comet have been combined together into a single picture. This is a composite image because a single exposure of the stellar background, Comet Siding Spring, and Mars would be problematic because the objects are all moving with respect to each other and the background stars. Hubble can only track one planetary target at a time. Also, Mars is actually 10,000 times brighter than the comet, and the exposure here has been adjusted so that details on the Red Planet can be seen.
Please join Hubble astronomers at 3pm EDT today for a live discussion at: Google+.
Here's Looking At You: Spooky Shadow Play Gives Jupiter a Giant Eye
The Hubble Space Telescope treats astronomers to gorgeous close-up views of the eerie outer planets. But it's a bit of a trick when it seems like the planet's looking back at you! In this view, the shadow of the Jovian moon Ganymede swept across the center of the Great Red Spot – a giant storm on the planet. This gave Jupiter the uncanny appearance of having a pupil in the center of a 10,000-mile-diameter "eye." Now if it blinks, we may really have to worry!
The universe is an infinite sea of galaxies, which are majestic star-cities. When galaxies group together in massive clusters, some of them can be ripped apart by the gravitational tug of other galaxies. It's a giant cosmic mosh pit. Astronomers using the Hubble Space Telescope to probe the massive galaxy cluster Abell 2744 – nicknamed Pandora's Cluster – have found forensic evidence of galaxies torn apart long ago. It's in the form of a phantom-like faint glow filling the space between the galaxies. This glow comes from stars scattered into intergalactic space as a result of a galaxy's disintegration.
Hubble Surveys Debris-Strewn Exoplanetary Construction Yards
Over the past few years, astronomers have found an incredible diversity in the architecture of exoplanetary systems, as well as the planets themselves. A survey using the sharp view of the Hubble Space Telescope has uncovered a similar diversity in the debris systems that coincide with the formation of exoplanets. These circumstellar dusty disks are likely generated by collisions between objects left over from planet formation around stars. The survey's results suggest that there is some sort of interdependence between a planet and the accompanying debris system.
The Party's Over for These Youthful Compact Galaxies
Hubble has uncovered young, massive, compact galaxies whose raucous star-making parties are ending early. The firestorm of star birth has blasted out most of the remaining gaseous fuel needed to make future generations of stars. Now the party's over for these gas-starved galaxies, and they are on track to possibly becoming so-called "red and dead galaxies," composed only of aging stars. An analysis of 12 merging galaxies is suggesting that energy from the star-birthing frenzy created powerful winds that are blowing out the gas, squelching future generations of stars. This activity occurred when the universe was half its current age of 13.7 billion years.
The graphic illustrates how a vibrant, star-forming galaxy quickly transforms into a sedate galaxy composed of old stars. The scenario begins when two galaxies merge (Panel 1), funneling a large amount of gas into the central region. The gas compresses, sparking a firestorm of star birth, which blows out most of the remaining star-forming gas (Panel 2). Devoid of its fuel, the galaxy settles into a quiet existence, composed of aging stars (Panel 3).
Hubble Goes High Def to Revisit the Iconic 'Pillars of Creation'
Although NASA's Hubble Space Telescope has taken many breathtaking images of the universe, one snapshot stands out from the rest: the iconic view of the so-called "Pillars of Creation." The jaw-dropping photo, taken in 1995, revealed never-before-seen details of three giant columns of cold gas bathed in the scorching ultraviolet light from a cluster of young, massive stars in a small region of the Eagle Nebula, or M16.
Though such butte-like features are common in star-forming regions, the M16 structures are by far the most photogenic and evocative. The Hubble image is so popular that it has appeared in movies and television shows, on tee-shirts and pillows, and even on a postage stamp. And now, in celebration of its 25th anniversary, Hubble has revisited the famous pillars, providing astronomers with a sharper and wider view, shown in the right-hand image. For comparison, the original 1995 Hubble image of the gaseous towers appears in the left-hand view. Streamers of gas can be seen bleeding off pillars as the intense radiation heats and evaporates it into space. Stars are being born deep inside the pillars.
Hubble's High-Definition Panoramic View of the Andromeda Galaxy
The largest NASA Hubble Space Telescope image ever assembled, this sweeping view of a portion of the Andromeda galaxy (M31) is the sharpest large composite image ever taken of our galactic neighbor. Though the galaxy is over 2 million light-years away, the Hubble telescope is powerful enough to resolve individual stars in a 61,000-light-year-long section of the galaxy's pancake-shaped disk. It's like photographing a beach and resolving individual grains of sand. And, there are lots of stars in this sweeping view – over 100 million, with some of them in thousands of star clusters seen embedded in the disk. This ambitious photographic cartography of the Andromeda galaxy represents a new benchmark for precision studies of large spiral galaxies which dominate the universe's population of over 100 billion galaxies. Never before have astronomers been able to see individual stars over a major portion of an external spiral galaxy. Most of the stars in the universe live inside such majestic star cities, and this is the first data that reveal populations of stars in context to their home galaxy.
The panorama is the product of the Panchromatic Hubble Andromeda Treasury (PHAT) program. Images were obtained from viewing the galaxy in near-ultraviolet, visible, and near-infrared wavelengths, using the Advanced Camera for Surveys and the Wide Field Camera 3 aboard Hubble. This view shows the galaxy in its natural visible-light color, as photographed with Hubble's Advanced Camera for Surveys in red and blue filters July 2010 through October 2013.
Hubble Discovers that Milky Way Core Drives Wind at 2 Million Miles Per Hour
At a time when our earliest human ancestors had recently mastered walking upright, the heart of our Milky Way galaxy underwent a titanic eruption, driving gases and other material outward at 2 million miles per hour. Now, at least 2 million years later, astronomers are witnessing the aftermath of the explosion: billowing clouds of gas towering about 30,000 light-years above and below the plane of our galaxy.
The enormous structure, dubbed the Fermi Bubbles, was discovered five years ago as a gamma-ray glow on the sky in the direction of the galactic center. The balloon-like features have since been observed in X-rays and radio waves. But astronomers needed NASA's Hubble Space Telescope to measure for the first time the velocity and composition of the mystery lobes. They now seek to calculate the mass of the material being blown out of our galaxy, which could lead them to determine the outburst's cause from several competing scenarios. The graphic shows how Hubble probed the light from a distant quasar to analyze the outflow. The quasar's light passed through one of the bubbles. Imprinted on that light is information about the outflow's speed, composition, and eventually mass.
At first glance, galaxy NGC 7714 resembles a partial golden ring from an amusement park ride. This unusual structure is a river of Sun-like stars that has been pulled deep into space by the gravitational tug of a bypassing galaxy (not seen in this Hubble Space Telescope photo). Though the universe is full of such colliding galaxies that are distorted in a gravitational taffy-pull, NGC 7714 is particularly striking for the seeming fluidity of the stars along a vast arc. The near-collision between the galaxies happened at least 100 million years ago.
Firing off a string of snapshots like a sports photographer at a NASCAR race, NASA's Hubble Space Telescope captured a rare look at three of Jupiter's largest moons zipping across the banded face of the gas-giant planet: Europa, Callisto, and Io. Jupiter's four largest moons can commonly be seen transiting the face of the giant planet and casting shadows onto its cloud tops. However, seeing three moons transiting the face of Jupiter at the same time is rare, occurring only once or twice a decade. Missing from the sequence, taken on January 24, 2015, is the moon Ganymede that was too far from Jupiter in angular separation to be part of the conjunction.
Join Hubble Heritage Team members during the live Hubble Hangout event at 3:00 pm (EST) today (Thursday, February 5) to learn more about Jupiter's rare triple-moon conjunction. Visit
Hubble Gets Best View of a Circumstellar Debris Disk Distorted by a Planet
Over a decade before planets were found orbiting normal stars, the astronomy world was intrigued by the discovery of a vast, edge-on, pancake-flat disk of dust and gas encircling the newborn star Beta Pictoris. It appeared to validate the hypothesis by the German philosopher Immanuel Kant, 230 years ago, that our solar system was born when planets condensed from nebular material in the plane of such a disk. (This model was independently proposed by French scholar Pierre-Simon Laplace in 1796.) Kant regarded the coplanar obits of the planets a fossil skeleton of the long-ago disintegrated disk. Though nearly two dozen circumstellar debris disks have been viewed by the Hubble Space Telescope to date, Beta Pictoris is the first and best example of what a forming young planetary system looks like. That's because it can be seen edge on, and it is the only disk to date where a planet has also been imaged. Hubble has been used to intensively study the disk for the past two decades and this latest picture – when compared to previous observations – shows that the disk particles appear to smoothly revolve around the star like a majestic carousel. Ground-based telescopes found a Jupiter-sized world embedded in the disk in 2009, and future observations may yield more planetary objects.
To learn more about Hubble and Beta Pictoris, join the live Hubble Hangout event at 3:00 pm (EST) on Thursday, February 19. Visit
Hubble Sees Supernova Split into Four Images by Cosmic Lens
Three-leaf clover plants abound everywhere: on lawns, in gardens, and in forests. But spotting a four-leaf clover is a rare, lucky find. Astronomers using the Hubble Space Telescope have found the equivalent of a four-leaf clover with the discovery of four images of the same supernova. The images are arranged around a giant foreground elliptical galaxy embedded in a cluster of galaxies. The arrangement forms a cross-shaped pattern called an Einstein Cross. The powerful gravity from both the elliptical galaxy and its galaxy cluster magnifies the light from the supernova behind them in an effect called gravitational lensing. The elliptical galaxy and its galaxy cluster, MACS J1149.6+2223, are 5 billion light-years away from Earth. The supernova behind it is 9.3 billion light-years away.
Once the four images fade away, astronomers predict they will have a rare opportunity to watch a rerun of the supernova's appearance. Computer models of the cluster predict that another image of the stellar blast will appear within five years. Astronomers may have missed an earlier appearance of the supernova in 1995. These multiple appearances of the exploding star are due to the various paths its divided light is taking through the maze of clumpy dark matter in the galactic grouping. Each image takes a different route through the cluster and arrives at a different time, due, in part, to differences in the length of the pathways the light follows to reach Earth.
Join Hubble astronomers during the live Hubble Hangout discussion at 3pm EST on Thurs., March 5, to learn still more.
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NASA's Hubble Observations Suggest Underground Ocean on Jupiter's Largest Moon
Nearly 500 million miles from the Sun lies a moon orbiting Jupiter that is slightly larger than the planet Mercury and may contain more water than all of Earth's oceans. Temperatures are so cold, though, that water on the surface freezes as hard as rock and the ocean lies roughly 100 miles below the crust. Nevertheless, where there is water there could be life as we know it. Identifying liquid water on other worlds — big or small — is crucial in the search for habitable planets beyond Earth. Though the presence of an ocean on Ganymede has been long predicted based on theoretical models, NASA's Hubble Space Telescope found the best evidence for it. Hubble was used to watch aurorae glowing above the moon's icy surface. The aurorae are tied to the moon's magnetic field, which descends right down to the core of Ganymede. A saline ocean would influence the dynamics of the magnetic field as it interacts with Jupiter's own immense magnetic field, which engulfs Ganymede. Because telescopes can't look inside planets or moons, tracing the magnetic field through aurorae is a unique way to probe the interior of another world.
In 2007, Dutch schoolteacher Hanny van Arkel discovered a never-before-seen ghostly structure near a galaxy, while she was participating in an online amateur scientist project called Galaxy Zoo. The galaxy hosts a bright quasar that may have illuminated the apparition by hitting it with a beam of light from hot gas around a central black hole. Astronomers eagerly used the Hubble Space Telescope to do follow-up observations, which revealed knots of dust and gas in the "greenish blob." Assuming that this feature could offer insights into the puzzling behavior of active galaxies, Bill Keel of the University of Alabama, Tuscaloosa, initiated a search for other similar phenomenon. After all, where there's one strange blob there could be more. Keel had 200 volunteers look at archival data of 15,000 galaxies hosting quasars. In the end, he found eight other galaxies with bright active nuclei that have illuminated material far outside the radius of the galaxy. The eerie structures have looping, spiral, and braided shapes. Hubble's images show that they are like the remnants of galaxy collisions.
Join Hubble scientists for a live Hubble Hangout discussion at 3pm EDT on Thurs., April 2, to learn even more. Visit: Quasars and Active Galactic Nuclei .
