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[托福阅读] 新托福阅读材料:CometsFoundOrbitingMonsterBlackHole(1)

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发表于 2012-8-14 23:21:39 | 显示全部楼层 |阅读模式
 Ghostly "comets" have been found orbiting near the mouth of a supermassive black hole, a new study says.  
9 y& U, |# b6 a7 ?  A team of European and U.S. astronomers recently used Japan's Suzaku space telescope to study radiation pouring out of a black hole that's ten million times the mass of our sun. This monster black hole sits at the core of the spiral galaxy NGC 1365, 56 million light-years from Earth.
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$ X/ U7 o( a: }( e/ F% ~  Thanks to a fortuitous alignment of the space telescope and the black hole, astronomers were able to detect weird, comet-shaped clouds orbiting close to the black hole at breakneck speeds of thousands of miles a second.+ M4 k7 H* W! {; _+ n
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  "Unlike mountain-size icy comets found in our solar system, the ones we are seeing are made of stellar-size, superhot gaseous remains of stars ripped apart by black holes," said study co-author James Reeves of Keele University in the U.K.
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  The unusual discovery suggests that all supermassive black holes might have comet-like clouds, which may change how astronomers model the way these cosmic predators devour their stellar prey, the study authors say.
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4 m( r! d/ M3 B+ q8 Y. L' [  u  "Comets" Seen Eclipsing the Black Hole
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+ d# X  C6 P" I2 Q* V  Matter is constantly falling into the supermassive black holes at the centers of galaxies, forming what are called accretion disks of superhot material that orbit the black holes.
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  A jet of high-energy particles streaming from the mouth of the black hole creates a bright point of light as seen by Suzaku's x-ray eye.  T- J; `& E0 w# f* n6 U
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  Similar to the way the moon blots out sunlight during a solar eclipse, the orbiting clouds darkened the team's x-ray readings as they passed between Earth and the central black hole in NGC 1365.
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