新托福阅读材料：CometsFoundOrbitingMonsterBlackHole(1)

　Ghostly "comets" have been found orbiting near the mouth of a supermassive black hole, a new study says.

 

　　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.

 

　　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.

 

　　"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.

 

　　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.

 

　　"Comets" Seen Eclipsing the Black Hole

 

　　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.

 

　　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.

 

　　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.