Animation created by SXS, the Simulating eXtreme Spacetimes (SXS) project (http://www.black-holes.org)

This simulation depicts the birth, 1.3 billion years ago, of the gravitational waves discovered by LIGO on September 14, 2015.  The waves are generated by two black holes that spiral around each other, then collide and merge. In the bright green regions, the waves stretch space; in the dark green regions, they squeeze space. As the black holes approach each other, the waves get stronger and the separation between them gets shorter, giving rise to what scientists refer to as a "chirp." The two black holes collide and merge into a new black hole, bringing the waves to a crescendo. The newborn black hole vibrates briefly, then becomes quiet and stops generating waves. The waves all depart from the black hole’s vicinity, traveling out into the universe, carrying news of the black holes’ collision.