For the first time, gravitational waves were detected the waves. LIGO researchers sensed a wave that stretched space by one part in 1021, making the entire Earth expand and contract by 1/100,000 of a nanometer, about the width of an atomic nucleus. The observation tests Einstein’s theory of gravity, the general theory of relativity, with unprecedented rigor and provides proof positive that black holes exist. The signal exceeds the “five-sigma” standard of statistical significance that physicists use to claim a discovery. Comparison with computer simulations reveals that the wave came from two objects 29 and 36 times as massive as the sun spiraling to within 210 kilometers of each other before merging. The collision produced an astounding, invisible explosion. Modeling shows that the final black hole totals 62 solar masses—3 solar masses less than the sum of the initial black holes. The missing mass vanished in gravitational radiation.
