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Latest Accretion disc Stories

2014-03-05 12:21:30

WASHINGTON, March 5, 2014 /PRNewswire-USNewswire/ -- Astronomers have used NASA's Chandra X-ray Observatory and the European Space Agency's (ESA's) XMM-Newton to show a supermassive black hole six billion light years from Earth is spinning extremely rapidly. This first direct measurement of the spin of such a distant black hole is an important advance for understanding how black holes grow over time. http://photos.prnewswire.com/prnvar/20081007/38461LOGO Black holes are defined by...

Be Star Black Hole
2014-01-17 08:27:04

[ Watch the Video: Turn About Is Fair Play - Black Hole Caught Orbiting A Star ] John P. Millis, PhD for redOrbit.com - Your Universe Online Black holes, by their very definition, are difficult to find. Their density is so great, that light cannot be given off directly, and photons that stray too close are absorbed into the gravitational well. So researchers have to rely on indirect evidence that a black hole is present by searching for their effects on other nearby objects....

Cosmic Turbulence Black Hole Formation
2013-08-16 09:31:01

John P. Millis, PhD for redOrbit.com - Your Universe Online The mechanism by which stars and black holes are formed in extreme cases of high mass density has puzzled astronomers since Johannes Kepler first laid out his laws of planetary motion some 400 years ago. In the most basic sense, a large cloud of gas condenses into a rotating disk. Mass is then directed towards the center of the cloud where, due to the increasing density, a stellar body is eventually formed. One challenge to...

Unraveling Galactic History Begins With A Black Hole's Spin
2013-07-30 14:11:38

Brett Smith for redOrbit.com - Your Universe Online A supermassive black hole is believed to sit at the center of each large galaxy, and a new technique designed to detect the dark abyss' spin could be the key to unraveling a galaxy's history. While black holes cannot be seen directly, their behavior can be determined by looking at how they affect nearby objects. A paper published in Monthly Notices of the Royal Astronomical Society describes a new technique that was developed by...

NASA X-Ray Observatories Reveal Black Hole Spin
2013-02-27 17:22:50

John P. Millis, PhD for redOrbit.com — Your Universe Online One of the challenges of studying black holes — incredibly dense stellar remnants arising from massive supernova explosions — is that it is extremely difficult to measure the spin of such objects. And it is this motion that is of particular interest, since Einstein´s theory of General Relativity predicts that the gravitational waves produced from their rotation can distort the very fabric of space-time...

Using Black Hole Disks And Jets To Explore The Limits Of Spacetime
2013-02-22 10:37:51

Watch the video "Magneto-Spin Alignment Effect Movie (Black Hole Jet)" April Flowers for redOrbit.com - Your Universe Online Black holes are voracious monsters at the center of galaxies that shape the growth and death of the stars around them with their tremendous gravitational pull and explosive ejections of energy.  "Over its lifetime, a black hole can release more energy than all the stars in a galaxy combined," explains“¯Roger Blandford, Stanford professor,...

Astronomers Measure Black Hole Radius
2012-09-27 19:16:53

Lee Rannals for redOrbit.com — Your Universe Online An international team of astronomers was able to measure the radius of a black hole for the first time. Researchers measured the radius of a black hole at the center of the galaxy M87, which lies about 50 million light-years away from the Milky Way. M87 has a black hole 6 billion times more massive than the Sun, and the team was able to observe the glow of matter near the edge of the black hole, or the "event horizon," using...

Standard Model Does Little To Explain Why Earth Is So Dry
2012-07-18 10:59:10

Lawrence LeBlond for redOrbit.com - Your Universe Online Despite seventy percent of the Earth´s surface being covered by water, in reality the whole of the planet is only made up of 1 percent water, making it relatively dry compared to the gas giants, such as Jupiter and Neptune. And now, that dryness, which has long perplexed scientists, has been explained by a team of scientists working at the Space Telescope Science Institute (STSI) in Baltimore, Maryland. The standard model...

Gamma Rays From Milky Way’s Past Show Historically Active Black Hole
2012-05-30 03:39:18

Lee Rannals for RedOrbit.com Gamma-ray beams seen in the Milky Way's central black hole suggest that the galaxy's center was much more active in the past, according to new research. Harvard University astrophysicists used an image taken by NASA's Fermi space telescope to reveal gamma-rays from the Milky Way millions of years ago. "These faint jets are a ghost or after-image of what existed a million years ago," Meng Su, an astronomer at the Harvard-Smithsonian Center for Astrophysics...


Latest Accretion disc Reference Libraries

8_2c71772f2c3a31994d5208d4518632494
2004-10-19 04:45:44

Cosmogony -- Cosmogony is the study of the origins of celestial objects. It is most commonly used to refer to the study of the origin of the solar system. Currently, the most widely accepted theory is that the solar system was formed roughly 5 billion years ago with the collapse of a nebula of gas and dust, likely caused by shock waves generated by a nearby supernova. The solar system would have formed as a member of a star cluster, now long-since dispersed throughout the Milky Way over...

6_1446abbc556d86191d7944d6c5cf68052
2004-10-19 04:45:43

X-ray Burster -- X-ray bursters are a class of binary stars which are luminous in X-rays. They contain a neutron star and a low-mass companion star. The companion fills its Roche lobe and therefore the neutron star is accreting matter from it. The inflowing gas forms an accretion disk around the neutron star. Sometimes X-ray bursters show a sudden increase in their X-ray luminosity, called X-ray burst. All properties of the X-ray bursts can be explained assuming that they result from...

6_c7a74d948ad4cfdc1dd54ceada2509fb2
2004-10-19 04:45:42

Seyfert Galaxy -- Seyfert galaxies are spiral or irregular galaxies containing an extremely bright nucleus, most likely caused by a supermassive black hole, that can sometimes outshine the surrounding galaxy. The light from the central nucleus varies in less than a year, which implies that the emitting region must be less than one light year across. They are named for the astronomer Carl Seyfert, who studied them extensively in the 1940s. They are a subclass of active galactic nuclei....

6_c74ddf89e1e986e7de2e5e2451d6b60b2
2004-10-19 04:45:41

Microquasar -- Microquasars are smaller cousins of quasars. They are named after quasars, as they have some common characteristics: strong and variable radio emission often seen as radio jets, and an accretion disk surrounding a black hole. In quasars, the black hole is supermassive (millions of solar masses) as in microquasars, the black hole mass is a few solar masses. In microquasars, the accreted mass comes from a normal star and the accretion disk is very luminous in optical regions...

6_75b9b62fd255ef9e172fae83099783a52
2004-10-19 04:45:41

Accretion Disk -- An accretion disk is a structure formed by material falling into a gravitational source. Conservation of angular momentum requires that, as a large cloud of material collapses inward, any small rotation it may have will increase. Centrifugal force causes the rotating cloud to collapse into a disk, and tidal effects will tend to align this disk's rotation with the rotation of the gravitational source in the center. Friction between the particles of the disk generates heat...

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Word of the Day
barghest
  • A goblin in English folklore, often appearing in the shape of a large dog and believed to portend imminent death or misfortune.
  • A ghost, wraith, hobgoblin, elf, or spirit.
The origin of 'barghest' is not known, but it may be from perhaps burh-ghest, town-ghost, or German Berg-geist (mountain spirit) or Bär-geist (bear-spirit).
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