NASA announced the discovery of JKCS04, a star cluster located about 10.2 billion light year away. It's the most distant and oldest galaxy cluster yet discovered, it beats the previous record holder by about a billion light years.
"This object is close to the distance limit expected for a galaxy cluster," said Stefano Andreon of the National Institute for Astrophysics in Milan. "We don't think gravity can work fast enough to make galaxy clusters much earlier."
JKCS041 was originally detected in 2006 in a survey from the United Kingdom Infrared Telescope. The distance to the cluster was then determined from optical and infrared observation. The Chandra data were the final - but crucial - piece of evidence as they showed that JKCS041 was, indeed, a genuine galaxy cluster.