This is the beginning of LIGO's beam tube. (credit: Eric Berger)

LIVINGSTON, Louisiana—In a large press event today, the scientists behind the LIGO experiment announced the first direct detection of gravitational waves, ripples in the fabric of space-time generated by strong gravitational interactions. The news, following weeks of rumors, confirms a major prediction of general relativity, and comes a century after Einstein first formulated the theory.

The waves, produced in the final moments of a black hole merger, arrived precisely at 5:51 in the morning (US Eastern), and were picked up by both LIGO detectors—one in Louisiana, one in Washington. Since the Louisiana detector picked up the signal a few milliseconds sooner, the event that produced the gravitational waves occurred in the Southern Hemisphere.

"The description of this observation is beautifully described in the Einstein theory of general relativity formulated 100 years ago," said MIT professor Rainer Weiss, part of the team that first proposed LIGO. He said it "comprises the first test of the theory in strong gravitation."

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