The explosive event, likely originating from a star cluster in a chaotic galaxy, brightened rapidly over weeks and continued emitting radio waves for over 1,000 Earth-days, resembling the echo of a single, very powerful explosion.

Add Yahoo as a preferred source to see more of our stories on Google. Billions of light years away in a remote part of the universe, two neutron stars - the ultradense remnants of dead stars - collided.