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 highest velocity material expelled in a cataclysmic, stellar explosion 10 years ago has been detected for the first time by the Hubble telescope's imaging spectrograph. The top image, taken with Hubble's visible-light camera, shows the orange-red rings surrounding Supernova 1987A in the Large Magellanic Cloud. The glowing debris of the supernova explosion, which occurred in February 1987, is at the center of the inner ring. The small, white square indicates the location of the imaging spectrograph aperture. The Hubble data in the middle panel [and a schematic representation in the bottom panel] shows the presence of glowing hydrogen expanding at a speed of 33 millio…
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As two NASA spacecraft speed toward a mid-year rendezvous with Mars, astronomers using the Hubble telescope are providing updated planetary weather reports to help plan the missions. Hubble's new images show that the "Martian invasion" of spacecraft will experience considerably different weather conditions than seen by the last U.S. spacecraft to land on Mars 21 years ago. Martian atmospheric conditions will affect the operation of both the Mars Pathfinder landing on July 4, 1997 and the September 11 arrival of the Mars Global Surveyor, which will map the planet from orbit. These two Hubble snapshots were taken barely three weeks after another Hubble observations of the…
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The Egg Nebula, also known as CRL 2688, is shown on the left as it appears in visible light and on the right as it looks in infrared light. Both Hubble views recount the last gasps of a dying, Sun-like star. Objects like the Egg Nebula are helping astronomers understand how stars like our Sun expel carbon and nitrogen – elements crucial for life – into space. Studies on the Egg Nebula show that these dying stars eject matter at high speeds along a preferred axis and may even have multiple jet-like outflows. The signature of the collision between this fast-moving material and the slower, out-flowing shells is the glow of hydrogen molecules [the red material] captured in …
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The colorful "zigzag" on the right is not the work of a flamboyant artist, but the signature of a super-massive black hole in the center of galaxy M84, discovered by the Hubble telescope's imaging spectrograph. The image on the left, also taken by Hubble, shows the core of the galaxy where the suspected black hole dwells. In a single exposure, astronomers mapped the motions of gas in the grip of the black hole's powerful gravitational pull by aligning Hubble's spectroscopic slit across the nucleus. View the full article
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The Hubble telescope's infrared vision is providing a dramatic new look at the beautiful Orion Nebula, which contains the nearest nursery for massive stars. For comparison, Hubble's visible-light view of the nebula is on the left. The heart of the giant Orion molecular cloud, OMC-1, is included in the relatively dim and featureless area inside the blue outline near the top of the image. Light from a few foreground stars provides only a hint of the many other stars embedded in this dense cloud. Hubble's infrared camera reveals a chaotic, active star birth region [as seen in the right-hand picture]. Here, stars and glowing interstellar dust, heated by and scattering the i…
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These pictures from the Hubble telescope's imaging spectrograph provide a new and unprecedented look at one of the most unique and complex structures in the universe – a light-year-wide ring of glowing gas around supernova 1987A, the nearest stellar explosion in 400 years The long-slit spectrograph viewed the entire ring system, dissecting its light and producing a detailed image of the ring in each of its component colors [the colorful loops on the right]. Each color represents light from specific elements in the ring's gases, including oxygen [single green ring], nitrogen and hydrogen [triple-orange rings], and sulfur [double-red rings]. By dismantling the ring into i…
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The Hubble telescope has made an important contribution toward solving one of astronomy's greatest enigmas by allowing astronomers to continue watching the fading visible-light counterpart of a gamma-ray burst, one of the most energetic and mysterious events in the universe. The so-called optical counterpart is presumably a cooling fireball from the catastrophic event that triggered the massive burst of invisible gamma rays – the highest-energy radiation in the universe. This event may have unleashed as much energy in a few seconds as the Sun does in 10 billion years! The orange dot in the center of this Hubble image represents the burst's visible-light glow. Vie…
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Completing an unprecedented yearlong study of Comet Hale-Bopp with two NASA observatories, including the Hubble telescope, astronomers report that they are surprised to find that the different ices in the nucleus seem to be isolated from each other. They also have seen unexpectedly brief and intense bursts of activity from the nucleus during the monitoring period. The Hubble observations suggest that the nucleus is huge, 19 to 25 miles (30 to 40 kilometers) across. Here are a series of Hubble telescope observations of the region around the nucleus of Hale-Bopp, taken on eight different dates since September 1995. They chronicle changes in the evolution of the nucleus as…
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The recently refurbished Hubble telescope obtained the sharpest view of Mars ever taken from Earth. This stunning portrait was taken with March 10, 1997, just before the Red Planet made one of its closest passes to Earth (about 60 million miles or 100 million kilometers). The Martian North Pole is at the top [near the center of the bright polar cap] and east is to the right. This view of Mars was taken on the last day of Martian spring in the Northern Hemisphere. View the full article
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The Space Telescope Science Institute (STScI) has selected fifteen young scientists for the 1997 Hubble Postdoctoral Fellowship Program. The awardees were selected from a pool of applications received from highly qualified candidates worldwide. View the full article
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The Hubble telescope is back at work, capturing this view of the butterfly-wing-shaped nebula, NGC 2346. The nebula is about 2,000 light-years away from Earth in the direction of the constellation Monoceros. It represents the spectacular "last gasp" of a double-star system at the nebula's center. The image was taken March 6, 1997 as part of the re-commissioning of Hubble's previously installed scientific instruments following a successful servicing mission. View the full article
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This Hubble telescope snapshot unveils a pair of one-half, light-year-long interstellar "twisters" – eerie funnels and twisted-rope structures [upper left] – in the heart of the Lagoon Nebula (M8) which lies 5,000 light-years from Earth in the direction of the constellation Sagittarius. The hot, central star, O Herschel 36 [upper left], is the primary source of the illuminating light for the brightest region in the nebula, called the Hourglass. The glare from this hot star is eroding the clouds by heating the hydrogen gas in them [seen as a blue "mist" at the right of the image]. This activity drives away violent stellar winds that are tearing into the cool clouds. …
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The Hubble telescope has found a long-sought population of "stellar outcasts" ? stars tossed out of their home galaxies into the dark emptiness of intergalactic space. This is the first time stars have been found more than 300,000 light-years (three Milky Way diameters) from the nearest big galaxy. The isolated stars dwell in the Virgo cluster of galaxies, about 60 million light-years from Earth. The results suggest this population of "lone stars" accounts for 10 percent of the Virgo cluster's mass, or 1 trillion Sun-like stars adrift among the 2,500 galaxies in Virgo. This is an illustration of the view of the nighttime sky from the surface of a hypothetical planet orb…
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Though the brightest supernova in four centuries lit up the southern sky almost exactly 10 years ago on Feb. 23, 1987, astronomers have waited a decade for the ballooning fireball to become large enough ? about one-sixth of a light-year ? to be resolved from Earth's orbit with the Hubble telescope. Hubble's sharp "eyes" have resolved a dumbbell-shaped structure ? one-tenth of a light-year long ? that consists of two blobs of debris expanding apart at nearly 6 million mph from each other. This Hubble picture shows the supernova, designated 1987A, and its neighborhood. The four frames follow the evolution of the supernova debris. View the full article
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Announcing the discovery of three black holes in three normal galaxies, astronomers suggest that nearly all galaxies may harbor super-massive black holes that once powered quasars (extremely luminous objects in the centers of galaxies), but are now quiescent. This conclusion is based on a census of 27 nearby galaxies carried out by the Hubble telescope and ground-based observatories in Hawaii. The three galaxies in these images are believed to contain central, super-massive black holes. The galaxy NGC 4486B [lower left] shows a double nucleus [lower right]. The picture at lower right is a close-up of the central region of NGC 4486B. View the full article
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Analyzing the pictures of some of the most distant galaxies in the universe, astronomers are uncovering intriguing new evidence that the Big Bang was followed by a stellar "baby boom." Hubble's unprecedented measurement of the rate of star birth in remote galaxies, which existed when the cosmos was less than 10 percent its current age, supports the emerging view that the early universe had an active, dynamic youth where stars formed out of dust and gas at a ferocious rate. The graph is based on observations of distant galaxies made by the Hubble telescope and ground-based observatories. Hubble shows a steep rise in star birth that happened shortly after the Big Bang. Th…
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This is the first direct image of a star other than the Sun. Called Alpha Orionis, or Betelgeuse, the star is a red super giant, a Sun-like star nearing the end of its life. The Hubble picture reveals a huge ultraviolet atmosphere with a mysterious hot spot on the stellar behemoth's surface. The enormous bright spot, twice the diameter of the Earth's orbit, is at least 2,000 degrees Kelvin hotter than the star's surface. View the full article
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Analysis of dramatic Hubble telescope images reveals immense comet-shaped knots of gas in the heart of the Cartwheel Galaxy. The galaxy's unusual wagon-wheel shape was created by a nearly head-on collision with a smaller galaxy about 200 million years ago. The discovery of the knots may eventually help answer some compelling questions, such as why the center of the Cartwheel has little star formation and what causes the unusual spoke-shaped pattern between the bright outer ring of young stars and the mysterious, dusty galactic center. The galaxy's center is the bright object in the center of the left-hand picture; the spoke-like structures are wisps of material connecti…
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Dramatic Hubble telescope pictures reveal that quasars live in a remarkable assortment of galaxies, many of which are violently colliding. This complicated picture suggests there may be a variety of mechanisms – some quite subtle – for "turning on" quasars, the universe's most energetic objects. When seen through ground-based telescopes, these compact, enigmatic light sources resemble stars, yet they are billions of light-years away and several hundred billion times brighter than normal stars. The following Hubble snapshots offer examples of quasar home sites. Astronomers believe that a quasar turns on when a massive black hole at the center of a galaxy feeds on gas and…
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Two Hubble telescope images of Mars, taken about a month apart, reveal a state-sized dust storm churning near the edge of the northern polar cap. The polar storm is probably a consequence of large temperature differences between the polar ice and the dark regions to the south, which are heated by the springtime sun. The increased sunlight also causes the dry ice in the polar cap to shrink. Mars is famous for large, planet-wide dust storms. This is the first time that such an event has been caught near the receding northern polar cap. In the top picture, the salmon-colored notch in the white northern polar cap is a 600-mile-long (1,000 kilometer-long) storm – nearly the …
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The Hubble telescope has been used to assemble a time-lapse color movie showing a full 16-hour rotation of the distant planet Neptune. The movie, made from a series of Hubble observations over nine consecutive orbits, allows astronomers to track cloud motion on the planet. The clear pictures reveal the planet's powerful equatorial jet stream, immense storms, and dark spot in the Northern Hemisphere. These snapshots provide views of the weather on opposite hemispheres. The photos disclose features of Neptune's blustery weather. View the full article
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The Hubble telescope's sharp view of the rapid, spectacular dance of luminescent gases high in Jupiter's atmosphere – better known as aurora – is allowing astronomers to map Jupiter's immense magnetic field and better understand how it generates such phenomena. The ultraviolet-light images [bottom frames] show how the auroral emissions change in brightness and shape as Jupiter rotates. The aurorae are the bright, circular features at the top and bottom of the planet. The top panel illustrates the effects of emissions from Io, one of Jupiter's moons. Io ejects an invisible electrical current of charged particles, which flow along the planet's magnetic field lines. …
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Clusters of stars and a fishhook-shaped cloud of luminescent gases glow brilliantly in NGC 2363, a giant star-forming region in the Magellanic galaxy NGC 2366. The brightest object visible in the Hubble telescope image [right] is a member of a rare class of stars called an erupting Luminous Blue Variable [at the tip of the fishhook]. This monstrous star (30 to 60 times as massive as the Sun) is in a very unstable, eruptive phase of its life. The Hubble telescope photo is the only one in which the star can be clearly isolated from the rest of the cluster. A view of this region from a terrestrial telescope is on the left. Only four giant eruptions of these special stars h…
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This image shows Jupiter's volcanic moon Io passing above the turbulent clouds of the giant planet. The conspicuous black spot on Jupiter is Io's shadow. This shadow is about the size of Io (2,262 miles or 3,640 kilometers across) and sweeps across the face of Jupiter at 38,000 mph (17 kilometers per second). The smallest details seen on Io and Jupiter are about 100 miles across. Bright patches visible on Io are regions of sulfur dioxide frost. Io is roughly the size of Earth's moon but 2,000 times farther away. View the full article
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New Hubble telescope images unveil what may be galaxies under construction in the early universe. Hubble's detailed pictures reveal a grouping of 18 gigantic star clusters that appear to be the same distance from Earth, and close enough to each other that they will eventually merge into a few galaxy- sized objects. They are so far away, 11 billion light-years, that they existed during the epoch when it is commonly believed galaxies started to form. These results add weight to a leading theory that galaxies grew by starting out as clumps of stars, which, through a complex series of encounters, consolidated into larger assemblages that we see as fully formed galaxies. …
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