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
Black Holes in Star Clusters stir up Time and Space (w/ Video)
Dec 16, 2009 |
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(PhysOrg.com) -- Within a decade scientists could be able to detect the merger of tens of pairs of black holes every year, according to a team of astronomers at the University of Bonn’s Argelander-Institut ...
Theorists propose a new way to shine -- and a new kind of star
Dec 14, 2009 |
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Dying, for stars, has just gotten more complicated. For some stellar objects, the final phase before or instead of collapsing into a black hole may be what a group of physicists is calling an electroweak star.
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 ...
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.
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. ...
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 ...
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 ...
Black hole caught zapping galaxy into existence?
Nov 30, 2009 |
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(PhysOrg.com) -- Which come first, the supermassive black holes that frantically devour matter or the enormous galaxies where they reside? A brand new scenario has emerged from a recent set of outstanding ...
Fermi Telescope Peers Deep into Microquasar (w/ Video)
Nov 27, 2009 |
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(PhysOrg.com) -- NASA's Fermi Gamma-ray Space Telescope has made the first unambiguous detection of high-energy gamma-rays from an enigmatic binary system known as Cygnus X-3. The system pairs a hot, massive ...
The Energy Sources of Ultraluminous Galaxies
Nov 27, 2009 |
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(PhysOrg.com) -- Ultraluminous infrared galaxies ((ULIRGs) are galaxies whose luminosity exceeds that of a trillion suns; for comparison, the Milky Way galaxy has a typical (and much more modest) luminosity ...
First black holes may have incubated in giant, starlike cocoons
Nov 24, 2009 |
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(PhysOrg.com) -- The first large black holes in the universe likely formed and grew deep inside gigantic, starlike cocoons that smothered their powerful x-ray radiation and prevented surrounding gases from ...
Mysterious X-rays from a Nearby Galaxy
Nov 13, 2009 |
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(PhysOrg.com) -- The nucleus of an active galaxy, an AGN, contains a massive black hole that is vigorously accreting material. In the process it typically ejects jets of particles and radiates brightly at ...
NASA's Great Observatories Celebrate International Year of Astronomy
Nov 10, 2009 |
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(PhysOrg.com) -- A never-before-seen view of the turbulent heart of our Milky Way galaxy is being unveiled by NASA on Nov. 10. This event will commemorate the 400 years since Galileo first turned his telescope ...
Swift, XMM-Newton satellites tune into a middleweight black hole
Nov 10, 2009 |
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(PhysOrg.com) -- While astronomers have studied lightweight and heavyweight black holes for decades, the evidence for black holes with intermediate masses has been much harder to come by. Now, astronomers ...
Stars Fueled by Dark Matter Could Hold Secrets to the Universe
Nov 03, 2009 |
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(PhysOrg.com) -- The first stars in the universe may have been very different from the stars we see today, yet they may hold clues to understanding some of the mysterious features of the universe. These "dark ...
