Astronomers have observed a distant galaxy as it looked just 650 million years after the Big Bang, making it the farthest galaxy to have its distance reliably measured.

Pascal Oesch at Yale University in New Haven, Connecticut, and his colleagues used a telescope at the W. M. Keck Observatory in Hawaii to study the galaxy EGS-zs8-1. To gauge its age, they measured how much its light had been stretched, or redshifted, as the light travelled across the expanding Universe. They found that the object is surprisingly bright and massive for such a young galaxy — a sign of rapid star formation.

Their analysis adds weight to a theory that the peculiar colours of early galaxies, compared to later objects, may be the result of interaction between these rapidly forming stars and the gas around them.

Astrophys. J. Lett. 804, L30 (2015)