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Black hole seen ripping star apart Two space observatories have provided the first strong evidence of a supermassive black hole stretching, tearing apart and partially gobbling up a star flung into reach of its enormous gravity, astronomers said. The event had long been predicted by theory but never confirmed. A powerful X-ray blast drew the attention of astronomers to the event, located near the center of a galaxy about 700 million light-years from Earth. The international team of astronomers believe gases from the star, heated to multimillion-degree temperatures as they fell toward the black hole near the heart of galaxy RX J1242-11, produced the blast. Astronomers said a star about the size of our sun neared the black hole after veering off course following a close encounter with another star. The tremendous gravity of the black hole, estimated to have a mass 100 million times that of our sun, then stretched the star to the point of breaking. "This is the ultimate David versus Goliath battle, but here David loses," said Gunther Hasinger, of the Max Planck Institute for Extraterrestrial Physics in Germany. The effect is the same that the tug of the moon has on the Earth's oceans, but with much more violent results. The black hole consumed an estimated 1 percent of the doomed star, flinging the rest out into space. "This unlucky star just wandered into the wrong neighborhood," said Stefanie Komossa, also of the Max Planck Institute. Astronomers used NASA's Chandra and the European Space Agency's XMM-Newton X-ray observatories to capture the event. Similar events are estimated to occur just once every 10,000 years in a typical galaxy. Astronomers have seen other similar X-ray blasts before, but never were able to pinpoint them at the center of a galaxy, where black holes lurk. The new observations also revealed the characteristic X-ray signature expected of the surroundings of a black hole. The blast first was seen in 1992 and remains visible as it fades, said Chandra press scientist Peter Edmonds, of the Harvard-Smithsonian Center for Astrophysics.
2007年01月02日 07点01分
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