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
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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 ...
Physicists Rule Out the Production of Dangerous Black Holes at the LHC
Sep 01, 2008 |
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(PhysOrg.com) -- On August 8, the world's largest particle accelerator, the Large Hadron Collider near Geneva, Switzerland, began the process of slowly throttling to full power. When its proton beams are circling ...
Qubits and Branes Share Surprising Features
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What do black holes and entangled particles have in common? Until about a year ago, physicists thought that the two entities existed in completely separate worlds. Then, in 2007, physicist Michael Duff from ...
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 ...
Chinese scientists create metamaterial black hole
Oct 16, 2009 |
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(PhysOrg.com) -- Two physicists in China have used metamaterials to create the first artificial electromagnetic black hole. The scientists, Qiang Cheng and Tie Jun Cui from the Southeast University in Nanjing, ...
Black Holes Go 'Mano a Mano'
Oct 06, 2009 |
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(PhysOrg.com) -- Two black holes in galaxy NGC 6240 are only 3,000 light years apart -- and getting closer.
Cosmic entropy could be 100 times greater than previously thought
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(PhysOrg.com) -- A new analysis of supermassive black holes has discovered the entropy of the universe is much greater than previously thought, which means it may also be very slightly closer to ultimate heat death.
Very High Energy Gamma Rays
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(PhysOrg.com) -- Gamma-rays are the most energetic known form of electromagnetic radiation, with each gamma ray being at least one hundred thousand times more energetic than an optical light photon. The most ...
New Vista of Milky Way Center Unveiled
Sep 22, 2009 |
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(PhysOrg.com) -- A dramatic new vista of the center of the Milky Way galaxy from NASA's Chandra X-ray Observatory exposes new levels of the complexity and intrigue in the Galactic center. The mosaic of ...
Invading black holes explain cosmic flashes
Sep 18, 2009 |
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(PhysOrg.com) -- Black holes are invading stars, providing a radical explanation to bright flashes in the universe that are one of the biggest mysteries in astronomy today.
'Metamaterials' used to look at effects of black holes, other celestial objects
Sep 10, 2009 |
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(PhysOrg.com) -- Dr. Dentcho Genov, an assistant professor of physics and electrical engineering at Louisiana Tech University and a Louisiana Optical Network Initiative (LONI) Institute fellow, is featured ...
Giant Galaxy Hosts the Most Distant Supermassive Black Hole
Sep 02, 2009 |
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(PhysOrg.com) -- University of Hawaii (UH) astronomer Dr. Tomotsugu Goto and colleagues have discovered a giant galaxy surrounding the most distant supermassive black hole ever found. The galaxy, so distant ...
Researchers propose new way to reproduce a black hole
Aug 21, 2009 |
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(PhysOrg.com) -- Despite their popularity in the science fiction genre, there is much to be learned about black holes, the mysterious regions in space once thought to be absent of light. In a paper published in the August ...
