As two black holes spiraled toward each other and merged, they created ripples in the fabric of the cosmos in exactly the form physicists have predicted for a century: gravitational waves. Unveiled today during a suite of international press conferences, the signal paves the way for a whole new understanding of the universe.

"This is the first time the universe has spoken to us through gravitational waves. Up until now we have been deaf,"LIGO Laboratory Director David Reitze, of the University of Florida, said today at a press event in Washington, D.C.

At the root of gravitational waves is Albert Einstein's theory of gravity, which says that anything with mass warps the very fabric of space-time. When massive objects move, they create distortions in the cosmic fabric, generating gravitational waves. These waves ripple through the universe like sound waves pulsing through the air.