The researchers said they identified gravitational waves coming from two distant black holes - extraordinarily dense objects whose existence also was foreseen by Einstein - that orbited one another, spiraled inward and smashed together at high speed to form a single, larger black hole.

The waves were unleashed by the collision of the black holes, one of them 29 times the mass of the sun and the other 36 times the solar mass, located 1.3 billion light years from Earth, the researchers said.

"Ladies and gentlemen, we have detected gravitational waves. We did it," said California Institute of Technology physicist David Reitze, triggering applause at a packed news conference in Washington.

"It's been a very long road, but this is just the beginning," Louisiana State University physicist Gabriela Gonzalez told the news conference, hailing the discovery as opening a new era in astronomy.