鸡生蛋还是蛋生鸡：宇宙学中的先有黑洞还是先有星系

Chicken-or-egg cosmology Galaxies and their supermassive black holes evolve together, but which came first is an ongoing question. Now, we may finally have an answer, says Leah Crane IF, AS novelist-philosopher Samuel Butler wrote in 1878, “a hen is only an egg’s way of making another egg”, then a galaxy may only be a black hole’s way of making another black hole. Or, in the problem of which came first, it seems the black hole wins out. Every massive galaxy we’ve seen, across the universe, has a supermassive black hole at its centre. The two are inextricably linked: all the stuff of the galaxy feeds the black hole, which, in turn, shapes the galaxy’s evolution. …