Zsuzsanna Marka, an astronomer at Columbia University, was sitting in an office on the morning of Jan. 4 when she got an email alert. She started to smile but then remembered she was not alone and the other person was not a member of LIGO, so she couldn’t say why she was smiling.

“I just kept smiling,” she said.

Upon further analysis it proved to be a perfect chirp, as predicted by Einstein’s equations. Because of the merger’s great distance, the LIGO scientists were able to verify that different frequencies of gravity waves all travel at the same speed, presumably the speed of light. As Dr. Reitze said, “Once again Einstein triumphs.”

“That’s not surprising,” Dr. Reitze went on, adding, “at some point he’s going to be wrong, and we’ll be looking.”

Poor Einstein.

Black holes were an entirely unwelcome consequence of his theory of general relativity that ascribes gravity to the warping of space-time geometry by matter and energy. Too much mass in one place, the equations said, could cause space to wrap itself around in a ball too tight and dense for even light to escape. In effect, Einstein’s theory suggested, matter, say a dead star, could disappear from the universe, leaving behind nothing but its gravitational ghost.

Einstein thought that nature would have more sense than that. But astronomers now agree that the sky is dotted with the dense dark remnants of stars that have burned up all their fuel and collapsed, often in gigantic supernova explosions. Until now, they were detectable only indirectly by the glow of X-rays or other radiation from doomed matter heated to stupendous degrees as it swirls around a cosmic drain.

But what telescopes cannot see, gadgets like LIGO now can feel, or “hear.”

Gravitational waves alternately stretch and squeeze space as they travel along at the speed of light. LIGO was designed to look for these changes by using lasers to monitor the distances between mirrors in a pair of L-shaped antennas in Hanford, Wash., and in Livingston, La. There is another antenna in Italy known as Virgo now undergoing its final testing. When it is online, possibly later this summer, having three detectors will greatly improve astronomers’ ability to tell where the gravitational waves are coming from.