It's the source of a long-standing cosmological quandary. Galaxies or black holes: Which came first? Today, they exist as neatly matched pairs, a black hole nested in the heart of a swirling galaxy, but it seems possible that the growth of one drove the growth of the other. By peering deep into the early universe, astronomers have edged ever closer to an answer. But they did not identify a leader of this cosmic tango, as galaxies and black holes appear to have matched each other step for step as early as a billion years after the universe began. Perhaps, then, they simply developed in tandem. [More]




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