Astronomy and Stars
Discussions about astronomy and stars. As we look further out what can we find in the universe beyond Earth's atmosphere?
2,069 topics in this forum
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The planets Neptune and Pluto have been selected as targets for original observations by students who will soon be serving as Hubble Space Telescope (HST) "Co-Investigators", working alongside some of America's foremost astronomers. In Spring 1996, for the first time ever, students in grades K-12 will have a chance to help do real science using the HST. The Space Telescope Science Institute (STScI), which oversees Hubble's science program for NASA and the European Space Agency, contributed three HST orbits to the PASSPORT TO KNOWLEDGE educational project for this purpose. View the full article
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The Hubble telescope has provided strong evidence for the existence of a roughly Jupiter-sized planet orbiting the star Beta Pictoris. Detailed Hubble snapshots of the inner region of the 200-billion-mile-wide dust disk encircling the star reveal an unexpected warp. Researchers say the warp can be best explained as caused by the tug of an unseen planet. This is a visible-light image of the disk, which looks like a spindle because it is tilted nearly edge-on to our view. The bright star, which lies at the center of the disk, is blocked out in this image. View the full article
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This Hubble telescope picture of planetary nebula NGC 7027 reveals remarkable new details of the process by which a star like the Sun dies. The nebula is a glowing record of the star's final death throes. New features include faint, blue, concentric shells surrounding the nebula; an extensive network of red dust clouds throughout the bright inner region; and the hot, central white dwarf, visible as a white dot at the center. View the full article
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This Hubble telescope picture of the Egg Nebula, also known as CRL2688, shows a pair of mysterious "searchlight" beams emerging from a hidden star and criss-crossed by numerous bright arcs. This image sheds new light on the poorly understood ejection of stellar matter that accompanies the slow death of Sun-like stars. The nebula is really a large cloud of dust and gas ejected by the star, expanding at a speed of 115,000 mph (20 km/s). A dense cocoon of dust [the dark band in the center] enshrouds the star and hides it from our view. Starlight escapes more easily in directions where the cocoon is thinner and is reflected towards us by dust particles in the cloud, giving …
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This Hubble telescope snapshot of MyCn18, a young planetary nebula, reveals that the object has an hourglass shape with an intricate pattern of "etchings" in its walls. A planetary nebula is the glowing relic of a dying, Sun-like star. The results are of great interest because they shed new light on the poorly understood ejection of stellar matter that accompanies the slow death of Sun-like stars. According to one theory on the formation of planetary nebulae, the hourglass shape is produced by the expansion of a fast stellar wind within a slowly expanding cloud, which is denser near its equator than near its poles. View the full article
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One peek into a small part of the sky, one giant leap back in time. The Hubble telescope has provided mankind's deepest, most detailed visible view of the universe. Representing a narrow "keyhole" view stretching to the visible horizon of the universe, the Hubble Deep Field image covers a speck of the sky only about the width of a dime 75 feet away. Though the field is a very small sample of the heavens, it is considered representative of the typical distribution of galaxies in space, because the universe, statistically, looks largely the same in all directions. Gazing into this small field, Hubble uncovered a bewildering assortment of at least 1,500galaxies at various …
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Confirming the presence of yet another super-massive black hole in the universe, astronomers using the Hubble telescope have found unexpected mysteries. The black hole and an 800-light-year-wide, spiral-shaped disk of dust fueling it are slightly offset from the center of the host galaxy, NGC 4261. Prior to Hubble observations, astronomers did not think dust was common in elliptical galaxies like NGC 4261, which were thought to have stopped making stars long ago due to the absence of the requisite raw materials: gas and dust. However, Hubble is showing that dust and dust disks are common in the centers of elliptical galaxies. View the full article
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The evidence consists of observations from 60-inch and 200-inch telescopes on Mount Palomar, and a confirmatory image from the Hubble telescope. The brown dwarf, called Gliese 229B (GL229B), is a small companion to the cool, red star Gliese 229, located 19 light-years from Earth in the constellation Lepus. Estimated to be 20 to 50 times the mass of Jupiter, GL229B is too massive and hot to be classified as a planet, but too small and cool to shine like a star. At least 100,000 times dimmer than Earth's Sun, the brown dwarf is the faintest object ever seen orbiting another star. View the full article
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Hubble Space Telescope evokes a new sense of awe and wonder about the infinite richness of our universe in dramatic, unprecedented pictures of celestial objects. Like a traveler sharing their best snapshots, we present a selection of Hubble's most spectacular images (1990-1995). View the full article
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This spectacular color panorama of the center of the Orion Nebula is one of the largest pictures ever assembled from individual images taken with the Hubble telescope. The seemingly infinite tapestry of rich detail revealed by Hubble shows a churning, turbulent star factory set within a maelstrom of flowing, luminescent gas. Though this 2.5-light-year-wide view is a small portion of the entire nebula, it includes a star cluster and almost all of the light from the bright glowing clouds of gas that make up the nebula. View the full article
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This Hubble telescope image of Jupiter [left] was taken when the giant planet was 534 million miles (854 million kilometers) from Earth. The arrow points to the predicted site at which the Galileo probe will enter Jupiter's atmosphere on December 7, 1995. At this latitude, the eastward winds have speeds of about 250 mph (110 meters per second). The white oval to the north of the probe site drifts westward at 13 mph (6 meters per second), rolling in the winds, which increase sharply toward the equator. The four enlarged Hubble images of Jupiter's equatorial region [right] show clouds sweeping across the predicted Galileo probe entry site, which is at the exact center of …
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By pinpointing individual suns in the glare of the most tightly packed cluster of stars in our galaxy, the Hubble telescope has unveiled hints of either a massive black hole or another remarkable phenomenon: a "core collapse" driven by the intense gravitational pull of so many stars in such a small volume of space. Astronomers used the telescope's sharp images to count an extraordinary number of stars in the ancient globular cluster M15, about 37,000 light-years from Earth. Hubble spied hundreds of stars in a tiny area at the center of this cluster. Careful analysis of the distribution of these and thousands of neighboring stars suggest that at some point in the distant…
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Eerie, dramatic pictures from the Hubble telescope show newborn stars emerging from "eggs" – not the barnyard variety – but rather, dense, compact pockets of interstellar gas called evaporating gaseous globules (EGGs). Hubble found the "EGGs," appropriately enough, in the Eagle nebula, a nearby star-forming region 7,000 light-years from Earth in the constellation Serpens. These striking pictures resolve the EGGs at the tip of finger-like features protruding from monstrous columns of cold gas and dust in the Eagle Nebula (also called M16). The columns – dubbed "elephant trunks" – protrude from the wall of a vast cloud of molecular hydrogen, like stalagmites rising above …
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The Hubble telescope has discovered a new, distant class of quadruple or cross-shaped gravitational lenses. The new class of objects might eventually provide astronomers with a powerful "magnifying glass" for probing a variety of characteristics of the universe: the distribution of dark matter, the abundance of super-massive black holes, and the eventual fate of the universe. In Hubble pictures of two such objects, astronomers have found four images of a faraway galaxy [the blue blobs] gathered around a red elliptical galaxy. A gravitational lens is produced by a massive object's enormous gravitational field, which bends light to magnify, brighten, and distort the image…
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Located approximately a half billion miles away, the moons are so small that, in visible light, they appear as fuzzy disks in the largest ground-based telescopes. Hubble can resolve surface details seen previously only by the Voyager space probes in the early 1980s. While the Voyager probes provided close-up snapshots of the satellites, Hubble can now follow changes on the moons and reveal other characteristics at ultraviolet and near-infrared wavelengths. View the full article
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Though ozone may be diminishing on Earth, it is being manufactured one-half billion miles away, on Jupiter's largest satellite, Ganymede. NASA's Hubble Space Telescope found ozone's spectral "fingerprint" during observations of Ganymede made by Keith Noll and colleagues at the Space Telescope Science Institute in Baltimore, Maryland. These Hubble Faint Object Spectrograph results were presented at the American Astronomical Society's 27th Annual Meeting of the Division of Planetary Sciences in Kona, Hawaii. View the full article
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This pair of images of Jupiter's volcanic moon Io, taken with the Hubble telescope, shows the surprising emergence of a 200-mile-wide, yellowish-white feature near the center of the moon's disk [photo on the right]. This represents a more dramatic change in 16 months than any seen over the previous 15 years, say researchers. They suggest the spot may be a new class of transient feature on the moon. For comparison the photo on the left was taken in March 1994, before the spot emerged. The photo indicates that Io's surface had undergone only subtle changes since it was last seen close-up by the Voyager 2 probe in 1979. View the full article
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This Hubble telescope image of a portion of a vast dust disk around the star Beta Pictoris [top picture] shows that the disk is thinner than previously thought. Estimates based on the Hubble snapshot place the disk's thickness as no more than one billion miles (600 million kilometers). For comparison the disk appears four times thicker in a ground-based image. The disk is tilted nearly edge-on to Earth and may be older than some previous estimates because its dust has had enough time to settle into a flat plane. A thin disk also increases the probability that comet-sized or larger bodies have formed through accretion in the disk. Both conditions are believed to be chara…
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The Hubble telescope has taken the first picture of bright aurorae at Saturn's northern and southern poles [top picture]. The picture at the bottom was taken in visible light. Hubble's far-ultraviolet-light image resolves a luminous, circular band centered on the north pole, where an enormous curtain of light rises as far as 1,200 miles (2,000 kilometers) above the cloud tops. This curtain changed rapidly in brightness and extent over the two-hour period of observations. View the full article
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These two surface maps of the asteroid Vesta are derived from Hubble telescope images taken between November 28 and December 1, 1994. The pictures show surface details as small as 35 miles across. Vesta is 320 miles in diameter, and the map covers the asteroid's entire surface area, about 200,000 miles. The top panel indicates sharp contrasts in Vesta's surface color. The surface markings may represent ancient volcanic activity such as lava flows and, in addition, regions where major collisions have stripped away the surface. The bottom panel reveals that Vesta's surface is made up of igneous rock, indicating that either the entire surface was once melted or lava flowin…
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These Hubble telescope pictures of comet Hale-Bopp show a remarkable "pinwheel" pattern and a blob of free-flying debris near its center. The image at left shows the entire comet; the picture at right is a close-up of the nucleus. The bright clump of light along the spiral [just above the center of the picture] may be a piece of the comet's icy crust. Although the "blob" is about 3.5 times fainter than the brightest portion at the comet's center, the lump appears brighter because it covers a larger area. The debris follows a spiral pattern outward because the solid center is rotating like a lawn sprinkler, completing a single rotation about once per week. View th…
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This Hubble telescope picture reveals one of the least massive and coolest stars ever seen [upper right]. This star is a diminutive companion to the K dwarf star called GL 105A (also known as HD 16160), seen at lower left. The pair is located 27 light-years from Earth in the constellation Cetus. Based on the Hubble observation, astronomers calculate that the cool, lightweight star, called GL 105C, is 25,000 times fainter than GL 105A in visible light. If the dim companion were at the distance of our Sun, it would be only four times brighter than the full moon. View the full article
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Peering deep into the globular star cluster M4 with the Hubble telescope, Canadian and American astronomers have discovered a large number of "stellar corpses," called white dwarf stars, which may be used eventually to refine age estimates of the universe. The observation was so sensitive that even the brightest of the detected white dwarfs was no more luminous than a 100-watt light bulb seen at the moon's distance (239,000 miles). A Hubble color image of a small portion of the cluster reveals eight white dwarf stars [inside the white circles] among the cluster's much brighter population of yellow, Sun-like stars and cooler red dwarf stars. Hubble reveals a total of 75 …
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Saturn's magnificent ring system is seen tilted edge-on - for the second time in 1995 - in this Hubble telescope picture taken Aug. 10, when the planet was 895 million miles (1,440 million kilometers) away from Earth. Hubble snapped the image as Earth sped back across Saturn's ring plane to the sunlit side of the rings. Several of Saturn's icy moons are visible as tiny star-like objects in or near the ring plane. On May 22, 1995 Earth dipped below the ring plane, giving observers a brief look at the backlit side of the rings. Ring-plane crossing events occur approximately every 15 years. Earthbound observers won't have as good a view until the year 2038. View the…
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Probing some of the most distant and energetic galaxies in the universe, the Hubble telescope has uncovered surprisingly varied and intricate structures of stars and gas, suggesting that the processes powering these so-called radio galaxies are more complex than previously thought. The radio galaxies observed are far across the cosmos, existing when the universe was half its present age. Light from these galaxies is just now reaching Earth. The Hubble observations should shed light on galaxy evolution and on the nature of active galaxies, which may be powered by immense black holes at their cores. These Hubble images, combined with radio maps produced by the Very Large …
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