Ancient Galaxy Megamergers
Astronomers have looked back in time to when the Universe was only a tenth of its current age...
...to see galaxy clusters — some of the most massive structures in the known Universe, as they form.
By looking 90% of the way across the observable Universe, astronomers caught groups of young galaxies about to collide.
These cosmic pile-ups will lead to the formation of colossal galaxy clusters — much earlier than astronomers expected.
Several telescopes — including ALMA, APEX and the VLT— teamed up to make this discovery possible...
...and let astronomers study galaxy clusters forming less than 1.5 billion years after the Big Bang.