On September 14, 2015 at 09:50:45 UTC the two detectors of the Laser Interferometer Gravitational-Wave Observatory simultaneously observed a transient gravitational-wave signal. The signal sweeps upwards in frequency from 35 to 250 Hz with a peak gravitational-wave strain of 1.0×10−21. It matches the waveform predicted by general relativity for the inspiral and merger of a pair of black holes and
![Observation of Gravitational Waves from a Binary Black Hole Merger](https://cdn-ak-scissors.b.st-hatena.com/image/square/872e17c27320d03c29010276e20004da0396400c/height=288;version=1;width=512/https%3A%2F%2Fcdn.journals.aps.org%2Fjournals%2FPRL%2Fkey_images%2F10.1103%2FPhysRevLett.116.061102.png)