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, the AP reports. They detected a second gravitational wave. That's the warp in the fabric in the cosmos that Albert Einstein predicted a century ago and only 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," a Louisiana State University physicist says.
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. "This event really does establish that there are quite a few merging black holes in the nearby universe," a Penn State University physicist says. "The universe is full of these tremendous collisions that are depositing tremendous energy." The latest sound was from a cosmic crash 1.4 billion light-years away. A light-year is 5.9 trillion miles. (Read more gravitational waves stories.)