Astronomy and Stars
Discussions about astronomy and stars. As we look further out what can we find in the universe beyond Earth's atmosphere?
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Two of the most reliable changes in the sky are the daily rising of the sun in the east and setting of the sun in the west. But if you lived on a couple of Pluto's moons you wouldn't know when the day would begin, or even what direction the sun would rise. That's because, unlike Earth's moon, at least two of Pluto's small moons, Hydra and Nix, are tumbling chaotically through space. Why? Because they orbit inside a dynamically shifting gravitational field caused by the system's two central bodies, Pluto and Charon, that are whirling around each other. The moons are also football shaped, and this contributes to the chaotic rotation. By contrast, Earth's moon keeps the sa…
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One of the trademarks of the Star Wars film episodes is the dreaded Death Star battle station that fires a beam of directed energy powerful enough to blow up planets. The real universe has such fireworks, and they are vastly more powerful than the Star Wars creation. These extragalactic jets are tearing across hundreds of light-years of space at 98 percent the speed of light. Instead of a battle station, the source of the killer beam is a supermassive black hole weighing many million or even a billion times the mass of our sun. Energy from the spinning black hole, and its titanic magnetic fields, shape a narrow jet of gas blasting out a galaxy's center. Hubble has been us…
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Astronomers have spent decades trying to determine the oddball behavior of an aging star nicknamed "Nasty 1" residing in our Milky Way galaxy. Nasty 1 was identified as a Wolf-Rayet star, a rapidly evolving star that is much more massive than our sun. The star loses its hydrogen-filled outer layers quickly, exposing its super-hot and extremely bright helium-burning core. But Nasty 1 doesn't look like a typical Wolf-Rayet star. Astronomers using NASA's Hubble Space Telescope had expected to see a bipolar outflow of twin lobes of gas from the star, perhaps similar to those emanating from the massive star Eta Carinae. The astronomers were surprised, however, to find a panc…
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Globular star clusters are isolated star cities, home to hundreds of thousands of stars. And like the fast pace of cities, there's plenty of action in these stellar metropolises. The stars are in constant motion, orbiting around the cluster's center. Past observations have shown that the heavyweight stars live in the crowded downtown, or core, and lightweight stars reside in the less populated suburbs. But as heavyweight stars age, they rapidly lose mass, cool down, and shut off their nuclear furnaces. After the purge, only the stars' bright, super-hot cores remain, and they are called white dwarfs. This weight-loss program causes the now lighter-weight white dwarfs to …
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The Andromeda galaxy is our Milky Way's nearest neighbor in space. The majestic spiral of over 100 billion stars is comparable in size to our home galaxy. At a distance of 2.5 million light-years, it is so close to us the galaxy can be seen as a cigar-shaped smudge of light high in the autumn sky. But if you could see the huge bubble of hot, diffuse plasma surrounding it, it would appear 100 times the angular diameter of the full Moon! The gargantuan halo is estimated to contain half the mass of the stars in the Andromeda galaxy itself. It can be thought of as the "atmosphere" of a galaxy. Astronomers using Hubble identified the gas in Andromeda's halo by measuring how it…
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The universe is incredibly big. But how do astronomers know that? Billion-mile-long tape measures can't be found at the hardware store. Instead, astronomers use the expansion of the universe itself to establish milepost markers. The light from remote objects is attenuated and weakened as space stretches like a rubber band. The consequences are that starlight will look redder relative to a nearby star of the same temperature. When starlight is spread into its component color via spectroscopy, features in the light will be shifted to the red end of the spectrum. This "redshift" can be used to reliably calibrate distances. The challenge is the farthest objects in the univers…
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NASA and ESA are celebrating the Hubble Space Telescope's silver anniversary of 25 years in space by unveiling some of nature's own fireworks – a giant cluster of about 3,000 stars called Westerlund 2. The cluster resides inside a vibrant stellar breeding ground known as Gum 29, located 20,000 light-years away in the constellation Carina. The comparatively young, 2-million-year-old star cluster contains some of our galaxy's hottest, brightest, and most massive stars. The largest stars are unleashing a torrent of ultraviolet light and hurricane-force winds that etch away the enveloping hydrogen gas cloud. This creates a fantasy celestial landscape of pillars, ridges, and v…
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Our Sun missed the stellar "baby boom" that erupted in our young Milky Way galaxy 10 billion years ago. During that time the Milky Way was churning out stars 30 times faster than it does today. Our galaxy was ablaze with a firestorm of star birth as its rich reservoir of hydrogen gas compressed under gravity, creating myriad stars. But our Sun was not one of them. It was a late "boomer," arising 5 billion years later, when star birth had plunged to a trickle. Astronomers compiled this story of our Milky Way's growth from studying galaxies similar in mass to our galaxy, found in deep surveys of the universe. Stretching back in time more than 10 billion years, the census …
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NASA and the Space Telescope Science Institute (STScI) have announced the selection of 17 new Hubble Fellows. STScI in Baltimore, Maryland, administers the Hubble Fellowship Program for NASA. The Hubble Fellowship Program includes all research relevant to present and future missions relating to NASA's Cosmic Origins Program. These missions currently include the Herschel Space Observatory, the Hubble Space Telescope (HST), the James Webb Space Telescope, the Stratospheric Observatory for Infrared Astronomy (SOFIA), and the Spitzer Space Telescope. The new Hubble Fellows will begin their programs in the fall of 2015. View the full article
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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 phenome…
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In particle physics labs, like the Large Hadron Collider in Geneva, Switzerland, scientists smash atoms together to study the underpinnings of matter and energy. On the scale of the macrocosm, nature provides a similar experiment by crashing clusters of galaxies together. Besides galaxies and gas, the galaxy clusters contain huge amounts of dark matter. Dark matter is a transparent form of matter that makes up most of the mass in the universe. During collisions, the clouds of gas enveloping the galaxies crash into each other and slow down or stop. Astronomers found that the dark matter continued straight through the violent collisions, without slowing down relative to the…
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Astronomers at the Space Telescope Science Institute and the Johns Hopkins University, both in Baltimore, Maryland, have created a new master catalog of astronomical objects called the Hubble Source Catalog. The catalog provides one-stop shopping for measurements of objects observed with NASA's Hubble Space Telescope. Hubble has amassed a rich legacy of images and other scientific data over its 25 years of exploring the universe. All of the images are stored in the computer-based Barbara A. Mikulski Archive for Space Telescopes (MAST), which astronomers use for their research. The archive is bursting with more than a million images, which contain roughly 100 million sma…
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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…
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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, MAC…
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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 Hubb…
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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 Herita…
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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. View the full article
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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…
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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 rep…
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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…
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It's the stuff of a science fiction movie: a mysterious form of energy that is pulling the universe apart at an ever-faster rate. Astronomers around the world are befuddled and are marshaling the world's most powerful telescopes in their search for clues to understanding what this "dark force" could be. Who knows how the story will end? This script was not written by Hollywood writers but by two teams of astronomers, including scientists at the Space Telescope Science Institute in Baltimore, Maryland. And now Hollywood has taken notice. The two groups received the $3 million Breakthrough Prize in Fundamental Physics. Adam Riess of the Space Telescope Science Institute a…
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The American Association for the Advancement of Science (AAAS) Council has elected Margaret Meixner of the Space Telescope Science Institute (STScI) and 401 other AAAS members as Fellows of AAAS. Election as an AAAS Fellow is an honor bestowed upon AAAS members by their peers. Meixner is cited by the AAAS for her "leadership in the area of infrared instrumentation for astronomy, both from the ground and from space and for distinguished service in science team management for the James Webb Space Telescope." The new Fellows will be formally announced in the AAAS News & Notes section of the journal Science on November 28, 2014. The new Fellows will be presented with an…
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The Association of Universities for Research in Astronomy (AURA) announced today that Dr. Matt Mountain, Director of the Space Telescope Science Institute in Baltimore, Maryland, will become AURA President beginning March 1, 2015. Mountain will succeed William S. Smith who served as President since 2000. In announcing the selection, the Chair of the AURA Board of Directors, Dr. Richard Green, said, "AURA is heading into an exciting period, and Matt has enormous experience in large program and large facility management in ground- and space-based organizations. This will be a great asset for AURA as we complete construction on the Daniel K. Inoue Solar Telescope, the Large …
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The Space Telescope Science Institute (STScI) in Baltimore, Maryland, has appointed Dr. Roeland van der Marel to lead its work on a proposed NASA space telescope that will provide images as sharp as the Hubble Space Telescope, but over a hundred times larger area. The space observatory, called the Wide-Field Infrared Survey Telescope-Astrophysics Focused Telescope Assets (WFIRST-AFTA), is being studied for launch in the mid-2020s, pending program approval by NASA. The telescope will be used to probe the distribution of dark matter and the characteristics of dark energy, measure the abundance and characteristics of planets orbiting other stars, and will provide observation…
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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 ill…
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