Galaxies in a cosmic house of mirrors

What happened

The brilliant golden galaxies splashed across this image belong to a galaxy cluster called MACS J0454.1-0300. While this galaxy cluster is a valuable scientific target in its own right, the real stars of this image are the galaxies that appear warped and stretched, like a painting that has been smeared by a giant hand.

The way these galaxies look is the result of gravitational lensing , in which the enormous mass of a foreground object such as a galaxy cluster bends and magnifies the light from a more distant object in the background. The gravitationally lensed areas show multiple images of galaxies from when the Universe was young: a group of galaxies 2 billion years after the Big Bang, and a single galaxy just 800 million years old after the Big Bang. The galaxy group appears to be going through a merger, resulting in an enormous burst of star formation.