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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The Hubble telescope is following dramatic and rapid changes in Jupiter's turbulent atmosphere that will be critical for planning observations for the Galileo space probe when it arrives at the giant planet later this year. This Hubble image provides a detailed look at a unique cluster of three white, oval-shaped storms that lie southwest [below and to the left] of Jupiter's Great Red Spot [dark oval-shaped object near the picture's right edge]. The appearance of the clouds is considerably different from their appearance only seven months earlier. Hubble shows these features moving closer together as the Great Red Spot is carried westward by the prevailing winds, while …
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The Space Telescope Science Institute (STScI) has selected 12 young scientists for the 1995 Hubble Postdoctoral Fellowship Program. The awardees were selected from a pool of applications from highly qualified candidates worldwide. Inaugurated in 1990, the Hubble Fellowship Program funds research opportunities for a significant fraction of the approximately 200 Ph.D. astronomers who graduate annually. The program is a joint venture between NASA and STScI, in cooperation with astronomical institutions across the United States. View the full article
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NASA's Hubble Space Telescope has helped solve a two-decade-old cosmic mystery by showing that mysterious clouds of hydrogen in space may actually be vast halos of gas surrounding galaxies. "This conclusion runs contrary to the longstanding belief that these clouds occur in intergalactic space," says Ken Lanzetta of the State University of New York at Stony Brook. View the full article
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What's the weather for Mars and Venus? The Hubble telescope has given astronomers a peek. The telescope is serving as an interplanetary weather satellite for studying the climate on Earth's neighboring worlds, Mars and Venus. To the surprise of researchers, Hubble is showing that the Martian climate has changed considerably since the unmanned Viking spacecraft visited the Red Planet in the mid-1970s. The Hubble pictures indicate that the planet is cooler, clearer, and drier than a couple of decades ago. In striking contrast, Hubble's observations of Venus show that the atmosphere continues to recover from an intense bout of sulfuric "acid rain," triggered by the suspect…
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In July 1994, 21 chunks of comet Shoemaker-Levy 9, which had broken apart a year earlier, slammed into Jupiter. The Hubble telescope recorded this spectacular event. These images, beginning at lower right, chronicle the results of one such collision. Hubble began snapping pictures of the impact area just five minutes after the collision. Nothing can be seen. Less than two hours later, a plume of dark debris is visible [bull's-eye pattern, image second from bottom]. Two impact sites are visible in the next picture, taken a few days later. The final snapshot shows three impact sites, the newest near the bull's-eye-shaped region. View the full article
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Astronomers using the Hubble telescope have identified the presence of an extremely tenuous atmosphere of molecular oxygen around Jupiter's moon, Europa. This makes Europa the first satellite ever found to have an oxygen atmosphere and only the third such solar system object beyond Earth to possess this gaseous element. If all the oxygen on Europa were compressed to the surface pressure of Earth's atmosphere, it would fill only about a dozen Astrodome-sized stadiums. View the full article
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This Hubble telescope image of the core of the nearest starburst spiral galaxy, NGC 253, reveals violent star formation within a region 1,000 light-years across. Hubble's sharp vision allows astronomers to see complex structures in the starburst core for the first time, including luminous star clusters, filaments of glowing gas, and dust lanes that trace regions of dense gas. Hubble identifies several regions of intense star formation, including a bright, super-compact star cluster. The entire galaxy is shown in the left-hand image, taken by a ground-based telescope. View the full article
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This Hubble telescope image shows a small portion of a nebula called the "Cygnus Loop." This nebula is an expanding blast wave from a stellar cataclysm, a supernova explosion, which occurred about 15,000 years ago. The supernova blast wave, which is moving from left to right across the picture, has recently hit a cloud of denser-than-average interstellar gas. This collision drives shock waves into the cloud that heats interstellar gas, causing it to glow. View the full article
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Astronomers using NASA's Hubble Space Telescope have discovered evidence that clouds of hydrogen found between galaxies at distances of billions of light-years from Earth are at least ten times larger than previously thought - at least one million light-years in diameter - and may have a remarkable sheet-like structure. View the full article
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Astronomers report today that new observations from the Hubble telescope challenge 30 years of scientific theory about quasars, the most energetic objects in the universe. Hubble images show, to the surprise of researchers, that the environment surrounding quasars is far more violent and complex than expected, providing evidence of galactic collisions and mergers. This Hubble picture provides evidence for a merger between a quasar and a companion galaxy. The bright central object is the quasar itself, located several billion light-years away. The two wisps on the left of the central object are remnants of a bright galaxy that have been disrupted by the mutual gravitatio…
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This Hubble telescope image shows one of the most complex planetary nebulae ever seen, NGC 6543, nicknamed the "Cat's Eye Nebula." Hubble reveals surprisingly intricate structures including concentric gas shells, jets of high-speed gas, and unusual shock-induced knots of gas. Estimated to be 1,000 years old, the nebula is a visual "fossil record" of the dynamics and late evolution of a dying star. A preliminary interpretation suggests that the object might be a double-star system. The dynamical effects of two stars orbiting one another most easily explains the intricate structures, which are much more complicated than features seen in most planetary nebulae. The two sta…
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A rare and spectacular head-on collision between two galaxies appears in this Hubble telescope picture of the Cartwheel Galaxy, located 500 million light-years from Earth in the constellation Sculptor. The striking ring-like feature is a direct result of a smaller intruder galaxy - possibly one of two objects to the right of the ring - that careened through the core [close-up image at lower left] of the host galaxy. Like a rock tossed into a lake, the collision sent a ripple of energy into space, plowing gas and dust in front of it. Expanding at 200,000 mph, this cosmic tsunami leaves in its wake a firestorm of new star creation. Hubble resolves bright blue knots that a…
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The Hubble telescope has uncovered surprising evidence that powerful magnetic fields may exist around the lowest mass stars in the universe, which barely have enough nuclear fuel to burn as stars. Hubble detected a high-temperature outburst, called a flare, on the surface of the extremely small, cool red dwarf star Van Biesbroeck 10, also known as Gliese 752B. Stellar flares are caused by intense, twisted magnetic fields that accelerate and contain gases that are much hotter than a star's surface. The illustration demonstrates the complex nature of this star. View the full article
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Darth Vader take heart. Astronomers have discovered a powerful ultraviolet laser beam, several times brighter than our Sun, shooting toward Earth from a super-hot "death star." The observations, made with the Hubble telescope, have identified a gas cloud that acts as a natural ultraviolet laser near the huge, unstable star called Eta Carinae ? one of the most massive and energetic stars in our Milky Way Galaxy. The interstellar laser may result from Eta Carinae's violently chaotic eruptions, in which it blasts parts of itself out into space, like an interstellar geyser. This illustration depicts a gas cloud [left], which acts as a natural ultraviolet laser near Eta Cari…
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This Hubble telescope picture of Saturn captures a rare storm that appears as a white arrowhead-shaped feature near the planet's equator. An upwelling of warmer air, similar to a terrestrial thunderhead, generates the storm. The east-west extent of this storm is equal to the diameter of the Earth (about 7,900 miles). Hubble provides new details about the effects of Saturn's prevailing winds on the storm. These winds shape a dark "wedge" that eats into the left side of the bright central cloud. The new image shows that the storm's motion and size have changed little since its discovery in September 1994. View the full article
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The Hubble telescope's crisp vision has captured a first-time view of one of the smallest stars in our Milky Way Galaxy. Called Gliese 623b or Gl623b, the diminutive star [right of center] is 10 times less massive than the Sun and 60,000 times fainter. (If it were as far away as the Sun, it would be only eight times brighter than the full Moon). Located 25 light-years from Earth in the constellation Hercules, Gl623b is the smaller component of a double-star system, where the separation between the two members is only twice the distance between Earth and the Sun (approximately 200 million miles). The small star completes one orbit around its larger companion every four y…
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This NASA Hubble Space Telescope (HST) image of the central portion of a remote cluster of galaxies (CL 0939+4713) as it looked when the universe was two-thirds of its present age. Hubble's high resolution allows astronomers to study, for the first time, the shapes of galaxies as they were long ago. The Space Telescope pictures are sharp enough to distinguish between various forms of spiral galaxies. Most of the spiral, or disk, galaxies have odd features, suggesting they were easily distorted within the environment of the rich cluster. Hubble reveals a number of mysterious "fragments" of galaxies interspersed through the cluster. View the full article
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Astronomers using the Hubble telescope as a "time machine" have obtained the clearest views yet of distant galaxies that existed when the universe was a fraction of its current age. A series of remarkable pictures, spanning the life history of the cosmos, are providing the first clues to the life history of galaxies. The Hubble results suggest that elliptical galaxies developed remarkably quickly into their present shapes. However, spiral galaxies that existed in large clusters evolved over a much longer period - the majority being built and then torn apart by dynamic processes in a restless universe. These pictures of faraway galaxies, located 5 to 10 billion light-yea…
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Scientists for the first time have made images of the surface of Saturn's giant, haze-shrouded moon, Titan. They mapped light and dark features over the surface of the satellite during nearly a complete 16-day rotation. One prominent bright area they discovered is a surface feature 2,500 miles across, about the size of the continent of Australia. Titan, which is larger than Mercury and slightly smaller than Mars, is the only body in the solar system, other than Earth, that may have oceans and rainfall on its surface. The oceans and rain are composed of ethane-methane rather than water. View the full article
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An international team of astronomers has uncovered a galaxy in our own cosmic back yard. Though only ten million light-years away (or five times the distance of the Andromeda galaxy - closest assemblage of stars to our Milky Way Galaxy), this newly discovered city of more than 100 billion stars has gone undetected previously because it is hidden from view behind our Milky Way galaxy. View the full article
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This Hubble telescope snapshot of the planet Uranus reveals the planet's rings, at least five of the inner moons, and bright clouds in the Southern Hemisphere. Hubble allows astronomers to revisit the planet at a level of detail not possible since the Voyager 2 spacecraft flew by the planet briefly, nearly a decade ago. This picture is a combination of images showing the motion of the inner moons. Each inner moon appears as a string of three dots. Thanks to Hubble's capabilities, astronomers will be able to precisely determine the moons' orbits. View the full article
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Astronomers using the Hubble telescope have announced the most accurate distance measurement yet to the remote galaxy M100, located in the Virgo cluster of galaxies. This measurement will help provide a precise calculation of the expansion rate of the universe, called the Hubble Constant, which is crucial to determining the age and size of the universe. They calculated the distance - 56 million light-years - by measuring the brightness of several Cepheid variable stars in the galaxy. Cepheid variables are a class of pulsating star used as "milepost markers" to calculate the distance to nearby galaxies. The bottom image shows a region of M100. This Hubble telescope image…
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The Hubble telescope has provided new insights into how stars may have formed many billions of years ago in the early universe. Hubble observations of a pair of star clusters suggest they might be linked through stellar evolution processes. The pair of clusters is 166,000 light-years from Earth in the Large Magellanic Cloud in the southern constellation Doradus. The clusters are unusually close together for being distinct and separate objects, suggesting that they might be evolutionary relatives. View the full article
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Until now, the dim, small stars were considered ideal candidates for dark matter. Whatever dark matter is, its gravitational pull ultimately will determine whether the universe will expand forever or will someday collapse. Picking a region in our Milky Way Galaxy, astronomers predicted that Hubble should have spied 38 red dwarf stars if this class of objects harbored most of the dark matter. The diamond-shaped symbols in the left-hand image illustrate what scientists expected to see. Instead, they saw no stars. View the full article
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This series of eight NASA Hubble Space Telescope "snapshots" shows the evolution of the P-Q complex, also called the "gang of four" region, of comet P/Shoemaker-Levy 9. The eight individual frames chronicle changes in the comet during the 12 months before colliding with Jupiter. The sequence shows that the relative separations of the various cometary fragments, thought to range in size from about 500 meters to almost 4 km (2.5 miles) across, changed dramatically over this period. The apparent separation of Q1 and Q2 was only about 1100 kilometers (680 miles) on 1 July 1993 and increased to 28,000 kilometers (17,400 miles) by 20 July 1994. View the full article
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