blockmemento

// block 397918 · science · 11 February 2016

Gravitational waves announced

The moment this block marks: the start of the NSF press conference in Washington, 10:30 local time, 11 February 2016, 15:30:00 UTC. The first block mined after it is block 397,918, 11 February 2016, 15:30:28 UTC.

For five months, the LIGO and Virgo collaborations had kept a secret. On 14 September 2015 the two LIGO detectors had recorded gravitational waves from a pair of colliding black holes, and since then hundreds of people had gone through the data to rule out every other explanation. The paper describing the result had been sent to Physical Review Letters, and the National Science Foundation had set a date for the announcement.

At 10:30 in the morning on 11 February 2016, at the National Press Club in Washington, the NSF director France Córdova opened the press conference. Soon after, David Reitze, executive director of the LIGO Laboratory, told the room, pausing between the words, that they had detected gravitational waves. The journalists applauded, and so did the collaboration members watching the live stream at the observatories in Hanford and Livingston, at Caltech, at MIT and around the world, free at last to talk about what they had found.

The announcement confirmed a prediction Einstein had made a century before, and opened a new way of studying the universe: by the vibrations of space itself rather than by light. Rainer Weiss, Kip Thorne and Barry Barish, who had led the building of LIGO, received the Nobel Prize in Physics the following year.

The first block mined after the conference opened, block 397,918, followed just 28 seconds later, while the NSF director was still opening the proceedings and before the discovery had been announced in the room. Its hash, like every hash, can be checked on any node.

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