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C. Black holes are hanging out at the center of our galaxy by the thousands, according to scientists who have detected a bunch of them in the neighborhood of a supermassive black hole already known to reside at the heart of the Milky Way. Researchers said data from the NASA's orbiting Chandra X-ray Observatory allowed them to detect a dozen black holes surrounding Sagittarius A, the mammoth black hole at the center of our spiral-shaped galaxy. Black holes, which ___24____ a variety of sizes, are extraordinarily dense entities with gravity so powerful that not even light can escape. Based on these findings, the scientists estimated that up to 10,000 black holes dwell within about 3 light years of Sagittarius A, boasting ___25____ our sun and located 26,000 light years from Earth. The newly detected black holes, all produced by the collapse of massive dying stars, are rare ones that captured and bound themselves to a passing star, forming what is called a stellar binary. Black holes ____26___ are hard to find, but the X-ray signatures of stellar binaries allowed their detection. "Black holes can form farther out from the center of the galaxy. They gravitationally interact with stars, cosmic collisions ___27___, and lose energy," one expert in NASA said. " As they lose energy, they sink to the center of the galaxy, the same way heavy sediment sinks faster than light sediment in water. They get captured by the gravity of the supermassive black hole, catch a star, and voila, you have something we can see X-rays from."
【題組】25.
(A) the mass of four million times
(B) four million times the mass of
(C) four million times big as
(D) four million bigger than

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108正式英師，感謝阿摩 高二下 (2019/05/08)
Based on these findings, the scientists estimated that up to 10,000 black holes dwell within about 3 light years of Sagittarius A, boasting four million times the mass of our sun and located 26,000 light ye.....觀看完整全文，請先登入


C. Black holes are hanging out at the c..-阿摩線上測驗