Before the discovery, every prediction from Einstein's theory had been proven by direct experimental evidence — except for the existence of gravitational waves.

David H. Reitze, executive director of the US observatory's laboratory, was quoted as saying, "Our observation of gravitational waves accomplishes an ambitious goal set more than five decades ago to directly detect this elusive phenomenon and better understand the universe. Fittingly, it fulfills Einstein's legacy after the 100th anniversary of his General Theory of Relativity."

British scientist Stephen Hawking said on his Facebook account, "It is thrilling to see predictions I made over 40 years ago ... being observed within my lifetime."

Before the discovery, the existence of gravitational waves had only been demonstrated by circumstantial evidence of observed in 1970s and 80s, which was awarded the Nobel Prize in Physics in 1993.