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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Less than 100 years ago scientists didn't know if the universe was coming or going, literally. It even fooled the great mind of Albert Einstein. He assumed the universe must be static. But to keep the universe from collapsing under gravity like a house of cards, Einstein hypothesized there was a repulsive force at work, called the cosmological constant, that counterbalanced gravity's tug. Along came Edwin Hubble in 1923 who found that galaxies were receding from us at a proportional rate, called the Hubble constant, which meant the universe was uniformly expanding, so there was no need to shore it up with any mysterious force from deep space. In measuring how this expansi…
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Bursts of star making in a galaxy have been compared to a Fourth of July fireworks display: They occur at a fast and furious pace, lighting up a region for a short time before winking out. But these fleeting starbursts are only pieces of the story, astronomers say. An analysis of archival images of small, or dwarf, galaxies taken by NASA's Hubble Space Telescope suggests that starbursts, intense regions of star formation, sweep across the whole galaxy and last 100 times longer than astronomers thought. The longer duration may affect how dwarf galaxies change over time, and therefore may shed light on galaxy evolution. View the full article
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Adam Riess was among 72 scientists elected today to membership in the National Academy of Sciences at the organization's 146th annual meeting, held in Washington, D.C. Riess, an astronomer at the Space Telescope Science Institute (STScI) and professor in the Henry A. Rowland Department of Physics and Astronomy in the Zanvyl Krieger School of Arts and Sciences, joins 20 other Johns Hopkins faculty members currently in the Academy, an honorary society that advises the government on scientific matters. View the full article
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Over the past 19 years Hubble has taken dozens of exotic pictures of galaxies going "bump in the night" as they collide with each other and have a variety of close encounters of the galactic kind. Just when you thought these interactions couldn't look any stranger, this image of a trio of galaxies, called Arp 194, looks like one of the galaxies has sprung a leak. The bright blue streamer is really a stretched spiral arm full of newborn blue stars. This typically happens when two galaxies interact and gravitationally tug at each other. Resembling a pair of owl eyes, the two nuclei of the colliding galaxies can be seen in the process of merging at the upper left. The blue…
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The most crowded collision of galaxy clusters has been identified by combining information from three different telescopes. This result gives scientists a chance to learn what happens when some of the largest objects in the universe go at each other in a cosmic free-for-all. Using data from NASA's Chandra X-ray Observatory, Hubble Space Telescope, and the Keck Observatory in Hawaii, astronomers were able to determine the three-dimensional geometry and motion in the system MACS J0717.5+3745 (or MACS J0717, for short), located about 5.4 billion light-years from Earth. View the full article
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In our violent, discordant, and effervescent universe, reality always seems to be stranger than fiction. Case in point: there is a galaxy 54 million light-years away that is shooting out a 5,000-light-year-long, narrow beam of radiation and plasma that is as opulent as a Star Wars light saber and as destructive as the film's Death Star. This extragalactic jet is being fueled and ejected from the vicinity of a monster black hole that is 3 billion times the mass of our Sun. The disk around a rapidly spinning black hole has magnetic field lines that entrap ionized gas falling toward the black hole. These particles, along with radiation, flow rapidly away from the black hole …
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On April 1-2, the Hubble Space Telescope photographed the winning target in the Space Telescope Science Institute's "You Decide" competition in celebration of the International Year of Astronomy (IYA). The winner is a group of galaxies called Arp 274. The striking object received 67,021 votes out of the nearly 140,000 votes cast for the six candidate targets. View the full article
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In 19 years of observations, the Hubble Space Telescope has amassed a huge archive of data. That archive may contain the telltale glow of undiscovered extrasolar planets, says David Lafrenière of the University of Toronto, Ontario, Canada. His team found the outermost of three massive planets known to orbit the young star HR 8799, which is 130 light-years away. The planetary trio was originally discovered in images taken with the Keck and Gemini North telescopes in 2007 and 2008. But using a new image processing technique that suppresses the glare of the parent star, Lafrenière found the telltale glow of the outermost planet in the system while studying Hubble archival da…
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Astronomers have detailed theories about what type of stars self-destruct in titanic supernova explosions. However, it would be useful to test stellar theory by actually seeing what a doomed star looked like before it blew apart. The problem is that a supernova blast pretty much eradicates all evidence of what the progenitor star was. Like a surveillance camera photographing the scene of a crime before it happened, the Hubble Space Telescope has a priceless archival photo of the galaxy that contains a picture of the supernova progenitor star as it appeared eight years before it exploded. The progenitor was comparatively easy to find because it was one of the brightest sta…
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Saturn's comparatively paper-thin rings are tilted edge on to Earth every 15 years. Because the orbits of Saturn's major satellites are in the ring plane, too, this alignment gives astronomers a rare opportunity to capture a truly spectacular parade of celestial bodies crossing the face of Saturn. Leading the parade is Saturn's giant moon Titan - larger than the planet Mercury. The frigid moon's thick nitrogen atmosphere is tinted orange with the smoggy byproducts of sunlight interacting with methane and nitrogen. Several of the much smaller icy moons that are closer in to the planet line up along the upper edge of the rings. Hubble's exquisite sharpness also reveals Satu…
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When it comes to finding dark matter in space, astronomers need to go on sort of a ghost hunt. Dark matter can't be directly seen or isolated in a laboratory. Yet it makes up the bulk of the matter in the universe. It is the invisible scaffolding for the formation of stars and galaxies. Dark matter is not made of the same stuff that stars, planets, and people are made of. That stuff is normal "baryonic" matter, consisting of electrons, protons, and neutrons. For 80 years astronomers have known about dark matter's "ghostly" pull on normal matter. They've known that without the gravitational "glue" of dark matter galaxy clusters would fly apart, and even galaxies would have…
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Though they are the largest and most widely scattered objects in the universe, galaxies do go bump in the night. The Hubble Space Telescope has photographed many pairs of galaxies colliding. Like snowflakes, no two examples look exactly alike. This is one of the most arresting galaxy smash-up images to date. At first glance, it looks as if a smaller galaxy has been caught in a tug-of-war between a Sumo-wrestler pair of elliptical galaxies. The hapless, mangled galaxy may have once looked more like our Milky Way, a pinwheel-shaped galaxy. But now that it's caught in a cosmic Cuisinart, its dust lanes are being stretched and warped by the tug of gravity. Unlike the ellipt…
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NASA has selected fellows in three areas of astronomy and astrophysics for its Einstein, Hubble, and Sagan Fellowships. The recipients of this year's postdoctoral fellowships will conduct independent research at institutions around the country. View the full article
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In 1609, Galileo first turned his telescope to the heavens and gave birth to modern astronomy. To commemorate four hundred years of exploring the universe, 2009 is designated the International Year of Astronomy. NASA's Great Observatories - the Hubble Space Telescope, Spitzer Space Telescope, and Chandra X-ray Observatory - are marking the occasion with the release of a suite of images at over 100 planetariums, museums, nature centers, and schools across the country in conjunction with Galileo's birthday on February 15. The selected sites will unveil a large, 9-square-foot print of the spiral galaxy Messier 101 that combines the optical view of Hubble, the infrared view o…
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In 1609, Galileo turned his telescope on the night sky for the first time. Now, 400 years later, your vote will help make the momentous decision of where to point modern astronomy's most famous telescope. "Hubble's Next Discovery, You Decide" is part of the International Year of Astronomy (IYA), the celebration of the 400th anniversary of Galileo's observations. People around the world can vote to select the next object the Hubble Space Telescope will view. Choose from a list of objects Hubble has never observed before and enter a drawing for one of 100 new Hubble pictures of the winning object. The winning image will be released between April 2 to 5, during the IYA's 1…
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The Hubble Space Telescope has imaged striking details of the famed planetary nebula designated NGC 2818, which lies in the southern constellation of Pyxis (the Compass). The spectacular structure of the planetary nebula contains the outer layers of a star that were expelled into interstellar space. The glowing gaseous shrouds in the nebula were shed by the central star after it ran out of fuel to sustain the nuclear reactions in its core. This Hubble image was taken in November 2008 with the Wide Field Planetary Camera 2. The colors in the image represent a range of emissions coming from the clouds of the nebula: red represents nitrogen, green represents hydrogen, and …
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Resembling comets streaking across the sky, these four speedy stars are plowing through regions of dense interstellar gas and creating brilliant arrowhead structures and trailing tails of glowing gas. The stars in these NASA Hubble Space Telescope images are among 14 young runaway stars spotted by the Advanced Camera for Surveys between October 2005 and July 2006. The images will be presented today at the American Astronomical Society meeting in Long Beach, Calif. View the full article
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This pair of NASA Hubble Space Telescope pictures shows the appearance of a mysterious burst of light that was detected on February 21, 2006, brightened over 100 days, and then faded into oblivion after another 100 days. The source of the outburst remains unidentified. The event was detected serendipitously in a Hubble search for supernovae in a distant cluster of galaxies. The light-signature of this event does not match the behavior of a supernova or any previously observed astronomical transient phenomenon in the universe. View the full article
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This composite color infrared image of the center of our Milky Way galaxy reveals a new population of massive stars and new details in complex structures in the hot ionized gas swirling around the central 300 light-years. This sweeping panorama is the sharpest infrared picture ever made of the Galactic core. It offers a nearby laboratory for how massive stars form and influence their environment in the often violent nuclear regions of other galaxies. This view combines the sharp imaging of the Hubble Space Telescope's Near Infrared Camera and Multi-Object Spectrometer (NICMOS) with color imagery from a previous Spitzer Space Telescope survey done with its Infrared Astrono…
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Brown dwarfs, objects that are less massive than stars but larger than planets, just got more elusive, based on studies of nearby multiple-star systems by NASA's Hubble Space Telescope. Hubble found only two brown dwarfs as companions to normal stars. This means the so-called "brown dwarf desert" (the absence of brown dwarfs around solar-type stars) extends to the smallest stars in the universe. The results are being reported today at the 213th meeting of the American Astronomical Society in Long Beach, Calif. View the full article
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NASA's Hubble Space Telescope has caught Jupiter's moon Ganymede playing a game of "peek-a-boo." In this crisp Hubble image, Ganymede is shown just before it ducks behind the giant planet. This color photo was made from three images taken on April 9, 2007, with the Wide Field Planetary Camera 2 in red, green, and blue filters. The image shows Jupiter and Ganymede in close to natural colors. View the full article
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NASA's Hubble Space Telescope has discovered carbon dioxide in the atmosphere of a planet orbiting another star. This is an important step along the trail of finding the chemical biotracers of extraterrestrial life as we know it. The Jupiter-sized planet, called HD 189733b, is too hot for life. But the Hubble observations are a proof-of-concept demonstration that the basic chemistry for life can be measured on planets orbiting other stars. Organic compounds can also be a by-product of life processes, and their detection on an Earth-like planet may someday provide the first evidence of life beyond Earth. View the full article
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Like a whirl of shiny flakes sparkling in a snow globe, NASA's Hubble Space Telescope catches an instantaneous glimpse of many hundreds of thousands of stars moving about in the globular cluster M13, one of the brightest and best-known globular clusters in the northern sky. This glittering metropolis of stars is easily found in the winter sky in the constellation Hercules. This image is a composite of archival Hubble data taken with the Wide Field Planetary Camera 2 and the Advanced Camera for Surveys. Observations from four separate science proposals taken in November 1999, April 2000, August 2005, and April 2006 were used. The image includes broadband filters that isola…
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Astronomers have long puzzled over why a small, nearby, isolated galaxy is pumping out new stars faster than any galaxy in our local neighborhood. Now NASA's Hubble Space Telescope has helped astronomers solve the mystery of the loner starburst galaxy, called NGC 1569, by showing that it is one and a half times farther away than astronomers thought. Hubble's Wide Field Planetary Camera 2 and Advanced Camera for Surveys made the observations of NGC 1569 in September 1999, November 2006, and January 2007. View the full article
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Astronomers using NASA's Hubble Space Telescope have taken the first visible-light snapshot of a planet orbiting another star. The images show the planet, named Fomalhaut b, as a tiny point source of light orbiting the nearby, bright southern star Fomalhaut, located 25 light-years away in the constellation Piscis Australis. An immense debris disk about 21.5 billion miles across surrounds the star. Fomalhaut b is orbiting 1.8 billion miles inside the disk's sharp inner edge. View the full article
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