“It looks like the black holes came first，”said Dr Chris Carilli，from the US National Radio Astronomy Observatory，who took part in the study.“The evidence is piling up.”

　　Earlier studies had revealed a link between the masses of black holes and the central “bulges” of stars and gas in galaxies.Generally，the black hole's mass was seen to be about one 1,000th the mass of the surrounding galactic bulge.This indicated a relationship between the black hole and the bulge.What was not clear was whether one grew before the other，or whether they grew together.

　　New radio telescope observations reaching back almost to the birth of the first galaxies may have answered that question.Radio waves received from these galaxies and traveling at the speed of light were sent out about a billion years after the Big Bang (大爆炸)which started the universe.These young distant galaxies had much larger black holes in relation to their bulge mass than older and closer galaxies.

　　“The implication is that the black holes started growing first，”said Dr Fabian Walter，from the Max­Planck Institute for Radio Astronomy in Germany.

　　The next challenge is to work out how the black hole and the bulge affect each other's growth，said the astronomers.

　　语篇解读：天文学上也有一个“先有鸡还是先有鸡蛋”的问题，即黑洞和星系哪一个先出现，对此科学家给出了答案。

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