WASHINGTON — Astronomers say they’ve heard the echoes of two more crashing black holes – a discovery that hints that the unseen violence of the universe may be pretty common.

They detected a second gravitational wave. That’s the warp in the fabric in the cosmos that Albert Einstein predicted a century ago in his theory of general relativity, something that results only from the most massive space crashes. It’s something that can’t be seen and Einstein thought would never be detected, but scientists have found a way to hear it – first one note, in September 2015, and now two.

“This is what we call gravity’s music,” Louisiana State University physicist Gabriela Gonzalez, scientific spokeswoman for the discovery team said at a Wednesday press conference where the sounds from the two gravitational waves were played.

With that second, higher pitch chirp, detected Christmas night in the United States, an international team of scientists have switched from reveling in the “aha” of first discovery to the more detailed and telling recording of the historical soundtrack of a chaotic universe. Astronomers announcing the sounds likened that soundtrack to jazz, maybe with a mix of classical music.

“These events – especially the first one – are the most powerful ones we have detected since the Big Bang,” said Barnard College physicist Janna Levin, author of “Black Hole Blues And Other Songs From Outer Space.”

Scientists first heard the cosmic crash after turning on their $1.1 billion set of twin instruments known as the Laser Interferometer Gravitational-wave Observatory , or LIGO. But physicists weren’t quite certain if they lucked into a once-in-a-lifetime chirp from a rare event or if these gravitational waves are out there waiting to be listened to on a regular basis.