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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Astronomers using the Hubble telescope have taken their first direct look in visible light at a lone neutron star. This view offers a unique opportunity to pinpoint the star's size and to narrow theories about the composition and structure of this bizarre class of gravitationally collapsed, burned out stars. The Hubble results show that the star [marked by white arrow] is very hot and can be no larger than 16.8 miles (28 kilometers) across. These findings prove that the object must be a neutron star, for no other known type of object can be this hot, small, and dim. View the full article
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Nova eruptions by dying stars were thought to be simple, predictable acts of violence. Astronomers could point a telescope at the most recently exploded novae and see an expanding bubble of gaseous debris around each star. Scientists using the Hubble telescope, however, were surprised to find that some nova outbursts may not produce smooth shells of gas, but thousands of gaseous blobs, each the size of our solar system. In this Hubble picture of the nova T Pyxidis, the shells of gas ejected by the star are actually more than 2,000 gaseous blobs packed into an area that is 1 light-year across. View the full article
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This Hubble telescope picture of Mars was taken Sept. 12, 1997, one day after the arrival of the Mars Global Surveyor (MGS) spacecraft and only five hours before the beginning of autumn in the Martian Northern Hemisphere. This Hubble picture was taken in support of the MGS mission. Hubble is monitoring Martian weather conditions, such as large dust storms, during the early phases of the spacecraft's aerobraking. View the full article
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Hubble telescope observations of the ever-fading fireball from one of the universe's most mysterious phenomena ? a gamma-ray burst ? is reinforcing the emerging view that these titanic explosions happen far away in other galaxies and are among the most spectacularly energetic events in the universe. In this Hubble image of the gamma-ray burst's visible-light component, the fireball has faded to 1/500th its brightness since its discovery in March 1997 by ground-based telescopes. Hubble continues to clearly see the fireball [center of picture] and a cloud of material surrounding it, which is considered to be its host galaxy. View the full article
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Probing the heart of the active galaxy NGC 6251, the Hubble telescope has provided a never-before-seen view of a warped disk or ring of dust caught in a blazing torrent of ultraviolet light from a suspected massive black hole. This discovery suggests that the environments around black holes may be more varied than thought previously and may provide a new link in the evolution of black holes in the centers of galaxies. This composite picture of the galaxy's core of the galaxy combines visible- and ultraviolet-light observations. While the visible-light image shows a dark dust disk, the ultraviolet image [color-coded blue] reveals a bright feature along one side of the di…
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Astronomers have used the Hubble Space telescope to discover a giant impact crater on the asteroid Vesta. The crater is a link in a chain of events thought responsible for forming a distinctive class of tiny asteroids as well as some meteorites that have reached the Earth. The giant crater is 285 miles across, which is nearly equal to Vesta's 330-mile diameter. If Earth had a crater of proportional size, it would fill the Pacific Ocean basin. Astronomers had predicted the existence of one or more large craters, reasoning that if Vesta is the true "parent body" of some smaller asteroids then it should have the wound of a major impact that was catastrophic enough to knock…
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Although the giant star Mira has been known for about 400 years, astronomers have had to wait for the Hubble telescope to provide the first ultraviolet-light images of the extended atmosphere of the cool red giant star and its nearby, hot companion. By giving astronomers a clear view of the individual members of this system, Hubble has provided valuable insights into other types of double-star systems where the stars are so close they interact with one another. In ultraviolet light, Hubble resolves a small, hook-like appendage extending from Mira and pointing towards the smaller companion. This material could be gravitationally drawn towards Mira's mate. View the…
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An international team of astronomers has discovered the most distant galaxy in the universe to date. They found it by combining the unique sharpness of the Hubble telescope with the light-collecting power of the W. M. Keck Telescopes – with an added boost from a gravitational lens in space. The results show the young galaxy is as far as 13 billion light-years from Earth, based on an estimated age for the universe of approximately 14 billion years. The Hubble picture at left shows the young galaxy as a red crescent to the lower right of center. The galaxy's image is brightened, magnified, and smeared into this arc-shape by the gravitational influence of an intervening ga…
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Astronomers using the Hubble telescope to track weather on Mars and how it might affect the Pathfinder landing site in Ares Vallis report that a large dust storm seen south of the site only 12 days earlier has dissipated. However, a new dust storm has appeared in the polar region, about 1,200 miles (2,000 kilometers) due north of the landing site. The Hubble researchers conclude that Pathfinder landed during a period when large changes in the regional distributions of dust and clouds were taking place on Mars. The green cross on the bottom picture identifies the Pathfinder landing site. View the full article
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Hubble telescope pictures of Mars, taken June 27, 1997 in preparation for the July 4 landing of the Pathfinder spacecraft, show a dust storm churning through the deep canyons of Valles Marineris, just 600 miles (1,000 kilometers) south of the Pathfinder spacecraft landing site. Astronomers also report the presence of patchy cirrus clouds over the landing site and very thick clouds to the north. Because there are so many clouds (related to low temperatures in the atmosphere causing water vapor to freeze), the dust will probably stay confined to the canyons, they conclude. The green cross on the bottom picture identifies the Pathfinder landing site. View the full a…
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The Hubble telescope has snapped a picture of a 400-kilometer-high (250-mile-high) plume of gas and dust from a volcanic eruption on Io, Jupiter's large, innermost moon. Io was passing in front of Jupiter when Hubble took this image. The plume appears as an orange patch just off the edge of Io [at eight o'clock], against the blue background of Jupiter's clouds. Io's volcanic eruptions blast material hundreds of kilometers into space in giant plumes of gas and dust. In this image, material must have been blown out of the volcano at more than 2,000 mph to form a plume of this size, which is the largest yet seen on Io. View the full article
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Nature's most powerful explosions, gamma-ray bursts, occur among the normal stellar population inside galaxies scattered across the universe. The energy released in such a titanic explosion, which can last from a fraction of a second to a few hundred seconds, is equal to all of the Sun's energy generated over its 10-billion-year lifetime. Here is the visible glow from one such burst, GRB 970228. This Hubble telescope picture is the first visible-light view ever taken that links a gamma-ray burst with a potential host galaxy. This observation provides strong supporting evidence that gamma-ray bursts are cosmological- they originate in distant galaxies across the universe…
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The visible fireball from a titanic explosion in deep space, called a gamma-ray burst, blazes in the center of this image, taken with the Hubble telescope's imaging spectrograph. The burst occurred on May 8, 1997, and Hubble observations to acquire the fading fireball were made on June 2. No accompanying object, such as a host galaxy, can be found near the burst. This result adds to the puzzlement over the source of these enigmatic explosions, because a previous Hubble picture of the visible glow from another gamma-ray burst identified a potential host galaxy. View the full article
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The Hubble telescope's infrared camera has peered into the Cone Nebula, revealing a stunning picture of six babies, Sun-like stars surrounding their mother, a bright, massive star. Known as NGC 2264 IRS, the massive star triggered the creation of these baby stars by releasing high-speed particles of dust and gas during its formative years. The image on the left, taken in visible light by a terrestrial telescope, shows the Cone Nebula, located 2,500 light-years away in the constellation Monoceros. The white box pinpoints the location of the star nursery, which cannot be seen in this image because dust and gas obscure it. The infrared image on the right shows the massive …
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The Hubble telescope's infrared camera has uncovered a collision between two spiral galaxies in the heart of the peculiar galaxy called Arp 220. The collision has provided the spark for a burst of star formation. Hubble's infrared vision has captured bright knots of stars forming in the heart of Arp 220. The bright, crescent, moon-shaped object is a remnant core of one of the colliding galaxies. The core is a cluster of 1 billion stars. The core's half-moon shape suggests that its bottom half is obscured by a disk of dust about 300 light-years across. This disk is embedded in the core and may be swirling around a black hole. The core of the other colliding galaxy is the…
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The Hubble telescope's imaging spectrograph simultaneously records, in unprecedented detail, the velocities of hundreds of gas knots streaming at hundreds of thousands of miles per hour from the nucleus of NGC 4151, thought to house a super-massive black hole. This is the first time the velocity structure in the heart of this object, or similar objects, has been mapped so vividly this close to its central black hole. The heart of NGC 4151 was captured in visible light in the upper left picture. In the other images, Hubble's imaging spectrograph has zeroed in on the galaxy's active central region. The Hubble data clearly show that the some material in the galaxy's hub is…
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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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