FILE - -In this photo taken Feb. 11, 2016, Laser Interferometer Gravitational-Wave Observatory (LIGO) Scientific Collaboration Spokesperson Gabriela Gonzalez holds up a scarf depicting gravitational waves for photographs following a news conference at the National Press Club in Washington, Thursday, Feb. 11, 2016, to announce that scientists they have finally detected gravitational waves, the ripples in the fabric of space-time that Einstein predicted a century ago. Astronomers say they???ve heard the echoes of yet 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. (AP Photo/Andrew Harnik, File)