Black hole
hideIn general relativity, a black hole is a region of space in which the gravitational field is so powerful that nothing, including light, can escape its pull. The black hole has a one-way surface, called an event horizon, into which objects can fall, but out of which nothing can come. It is called "black" because it absorbs all the light that hits it, reflecting nothing, just like a perfect blackbody in thermodynamics. Quantum analysis of black holes shows them to possess a temperature and Hawking radiation.
Despite its invisible interior, a black hole can reveal its presence through interaction with other matter. A black hole can be inferred by tracking the movement of a group of stars that orbit a region in space which looks empty. Alternatively, one can see gas falling into a relatively small black hole, from a companion star. This gas spirals inward, heating up to very high temperature and emitting large amounts of radiation that can be detected from earthbound and earth-orbiting telescopes. Such observations have resulted in the scientific consensus that, barring a breakdown in our understanding of nature, black holes do exist in our universe.
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News tagged with black holes
Scientists Generate Black Hole Radiation in the Lab
Dec 07, 2009 |
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(PhysOrg.com) -- Due to their violent nature and long distance from Earth, black holes and their surroundings are very difficult to study. Currently, the main method to observe a black hole is to use an X-ray ...
Suzaku catches retreat of a black hole's disk
Dec 10, 2009 |
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(PhysOrg.com) -- Studies of one of the galaxy's most active black-hole binaries reveal a dramatic change that will help scientists better understand how these systems expel fast-moving particle jets.
Scientists observe super-massive black holes using Keck Observatory in Hawaii
Dec 10, 2009 |
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An international team of scientists has observed four super-massive black holes at the center of galaxies, which may provide new information on how these central black hole systems operate. Their findings ...
RIT astronomer mines Spitzer Space Telescope data for massive starbursts
Dec 08, 2009 |
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Understanding the evolution of galaxies is one of the biggest questions confronting astronomers today. Looking at distant astronomical objects gives scientists important clues to the origins of the Milky Way Galaxy and other ...
XMM-Newton celebrates decade of discovery
Space & Earth / Space Exploration
Dec 09, 2009 |
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(PhysOrg.com) -- ESA's XMM-Newton X-ray observatory is celebrating its 10th anniversary. During its decade of operation, this remarkable space observatory has supplied new data for every aspect of astronomy. ...
