![An artist's illustration of two black holes merging.](https://cdn.mos.cms.futurecdn.net/PzTnxiJLxCaBbQPLmtzevN-320-80.jpg)
Astronomers discover the 1st-ever merging galaxy cores at cosmic dawn
Two superluminous quasars, or active black holes at the centers of large galaxies, were found just 900 million years after the Big Bang — the earliest detection of a pair of merging quasars ever seen.