The Olympics may be over, but in outer space, records are still being broken.
Scientist announced Wednesday the discovery of the Phoenix cluster, one of the most massive and luminous galaxy clusters ever identified. It's about 5.7 billion light years away, so we are getting a sense of it as it was at that time, billions of years ago.
The cluster has a mass of 2,500 trillion times that of our sun, said Michael McDonald, researcher at Massachusetts Institute of Technology, in a news conference Wednesday. It contains hundreds of thousands of galaxies the size of the Milky Way, in addition to dark matter and hot gas.