Locating gravity wave source. The Fermi Gamma-ray Space Telescope's Gamma-ray Burst Monitor (GBM) detected a fading X-ray flash at nearly the same moment LIGO (Laser Interferometer Gravitational-Wave Observatory) detected gravitational waves from a black hole merger in September 2015. It is likely that the two events are connected, and using the data from both observations has allowed scientists to narrow the area of search for the source. Gravity is the distortion of space-time by mass, and changes in this distortion travel in waves at the speed of light, as predicted by Einstein's theory of general relativity. The effect is most pronounced where extremely massive objects are subject to extremely high acceleration, for instance where black holes or neutron stars are in a close orbit.