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 has detected a long-sought population of comets dwelling at the icy fringe of the solar system. The observation, which is the astronomical equivalent to finding the proverbial needle-in-a-haystack, bolsters proof for a primordial comet reservoir just beyond Neptune. The circles pinpoint one of the candidate Kuiper belt objects. The dotted lines represent a possible orbit that this Kuiper belt comet is following. Based on the Hubble observations, a team of astronomers estimate that the belt contains at least 200 million comets, which have remained essentially unchanged since the birth of the solar system 4.5 billion years ago. View the full ar…
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Astronomers using the Hopkins Ultraviolet Telescope (HUT), flown aboard the Shuttle ASTRO-2 mission, have been able to exclude one explanation for the mysterious far ultraviolet background radiation that existed when the universe was young. They find that starburst galaxies -- galaxies forming new stars at an extremely high rate -- were largely opaque to the UV radiation from hot newborn stars embedded within them. Contrary to earlier ideas, this means that starburst galaxies did not contribute significantly to heating, or ionizing, the early universe. View the full article
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Observations with the Hopkins Ultraviolet Telescope (HUT) of the most massive star currently known have revealed new features of its hot outer layers, which are being blown away from the star at speeds of up to 2300 miles per second due to its extreme luminous energy output. These features in turn provide information about physical characteristics of the star, such as its temperature, luminosity, chemical composition, age, and mass, or the total amount of matter it contains. View the full article
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The Hubble telescope has provided a detailed look at the fitful, eruptive, and dynamic processes accompanying the final stages of a star's "construction." These three images provide a dramatically clear look at collapsing circumstellar disks of dust and gas that build stars and provide the ingredients for a planetary system. The pictures also show blowtorch-like jets of hot gas funneled from deep within several embryonic systems and machine gun-like bursts of material fired from the stars at speeds of a half-million mph. The Hubble observations shed new light on one of modern astronomy's central questions: How do tenuous clouds of interstellar gas and dust make stars li…
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This sequence of images from the Hubble telescope documents a rare astronomical alignment: Saturn's magnificent ring system turned edge-on. This event occurs when the Earth passes through Saturn's ring plane, as it does about every 15 years. In these pictures, Hubble can see details on Saturn as small as 450 miles (725 kilometers) across. In each image the dark band across Saturn is the ring shadow cast by the Sun, which is still slightly above the planet's ring plane. The bright dots to the left of Saturn and in the boxes to the right are some of the planet's moons. The boxes around the western portion of the rings [on the right] indicate the area in which the faint li…
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Peering into the heart of two recently exploded double-star systems, the Hubble telescope has surprised researchers by finding that the white dwarf stars at the center of the fireworks are cooler than expected and spin more slowly than previously thought. Each dwarf - dense, burned-out stars that have collapsed to the size of Earth - is in a compact binary system, called a cataclysmic variable, where its companion is a normal star similar to, but smaller than the Sun. The stars are so close together that the entire binary system would fit inside the Sun. Their closeness allows gas to flow from the normal star onto the dwarf, where it swirls into a pancake-shaped disk [s…
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Hubble telescope images of the asteroid Vesta are providing astronomers with a glimpse of the oldest terrain ever seen in the solar system and a peek into a broken-off section of the "mini-planet," which exposes its interior. Hubble's pictures provide the best view yet of Vesta's complex surface, which has geologic features similar to those of terrestrial worlds such as Earth or Mars. The asteroid's ancient surface, battered by collisions eons ago, allows astronomers to peer below the asteroid's crust and into its past. These images trace the asteroid through a full rotation. View the full article
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The distant, blue-green planet Neptune has again surprised astronomers with the emergence of a new great dark spot in the cloudy planet's Northern Hemisphere, discovered by the Hubble telescope. Only last June, Hubble images revealed that a great dark spot in the Southern Hemisphere discovered by the Voyager 2 spacecraft during its 1989 flyby had mysteriously disappeared. The new dark spot is a near mirror image of the one found in the Southern Hemisphere. Bright, high-altitude clouds accompany the new northern dark spot. Atmospheric gases that flow up over the spot cool to form the methane-ice crystal clouds. The new spot might be a hole in Neptune's methane cloud tops…
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This is a Hubble telescope image of the tattered debris of a star that exploded 3,000 years ago as a supernova. This supernova remnant, called N132D, lies 169,000 light-years from Earth in the satellite galaxy, the Large Magellanic Cloud. A Hubble snapshot of the supernova's inner regions shows the complex collisions that take place as fast-moving material slams into cool, dense interstellar clouds. This level of detail in the expanding filaments could only be seen previously in much closer supernova remnants. Now, Hubble's capabilities extend the detailed study of supernovae to the distance of a neighboring galaxy. View the full article
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This Hubble telescope image of a rich cluster of galaxies called Abell 2218 is a spectacular example of gravitational lensing. The arc-like pattern spread across the picture like a spider web is an illusion caused by the cluster's gravitational field. This cluster of galaxies is so massive and compact that light rays passing through it are deflected by its enormous gravitational field, much as a camera's lens bends light to form an image. This phenomenon magnifies, brightens, and distorts images of those faraway objects, providing a powerful "zoom lens" for viewing galaxies that are so far away they could not normally be observed with the largest telescopes. View…
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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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