問題詳情

C.Black holes are hanging out at the center of our galaxy by the thousands, according to scientists who have detected a bunchof them in the neighborhood of a supermassive black hole already known to reside at the heart of the Milky Way. Researcherssaid data from the NASA's orbiting Chandra X-ray Observatory allowed them to detect a dozen black holes surroundingSagittarius 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 scientistsestimated that up to 10,000 black holes dwell within about 3 light years of Sagittarius A, boasting ___25____ our sun and located26,000 light years from Earth. The newly detected black holes, all produced by the collapse of massive dying stars, are rare onesthat captured and bound themselves to a passing star, forming what is called a stellar binary. Black holes ____26___ are hard tofind, but the X-ray signatures of stellar binaries allowed their detection. "Black holes can form farther out from the center of thegalaxy. They gravitationally interact with stars, cosmic collisions ___27___, and lose energy," one expert in NASA said. " Asthey 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-raysfrom."
24.
(A) grow in
(B) hold on
(C) come in
(D) ward off

參考答案

答案：C
難度：適中0.5
統計：A(0),B(0),C(0),D(0),E(0)

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