Two black holes merged despite being born far apart in space

The black holes found each other late in life before colliding

Illustration of two black holes merging and emitting gravitational waves. The black holes, illustrated as dark spheres, have green arrows indicating spin in opposite directions

A detection of gravitational waves (illustrated) from the merger of two black holes that spin in different directions (green arrows) suggests they were born in very different places. If so, it’s the first time that kind of merger has been detected.

C. Henze/Ames Research Center/NASA

Signals buried deep in data from gravitational wave observatories imply a collision of two black holes that were clearly born in different places.