By Andy Coghlan
Just two years after their discovery, gravitational waves have earned a Nobel prize for Rainer Weiss, Barry Barish and Kip Thorne, the three leaders of the LIGO/VIRGO collaboration that found the waves on 14 September 2015. The discovery, which was announced publicly in 2016, confirmed predictions made 100 years ago by Albert Einstein.
Half of the $1.1 million prize went to Weiss, the remainder shared between Barish and Thorne. “It’s really wonderful, but I view this more as recognition of around 1000 people who contributed and a result of dedicated efforts over 40 years,” said Weiss, reacting to the announcement.
“The discovery, the first ever observation of gravity waves, is a milestone opening a new window into the universe,” said Olga Botner of Uppsala University in Sweden, and a member of the Nobel committee for Physics that awarded the prize. “Einstein was obviously right again, and the prize goes to the leaders of the international team for the discovery that shook the world.”
They were detected within 69 milliseconds apart at LIGO’s major detectors. The first trace at Hanford, Washington state, matched almost exactly the second at Livingston, Louisiana, 3000 kilometres away. Their perfect overlap allowed the team to rule out a false signal, said Botner.
LIGO used a pair of laser interferometers to measure a change thousands of times smaller than an atomic nucleus as the wave passed through the Earth. “The detectors are amazingly sensitive,” said Botner.
Weiss’s major contribution back in the 1970s at MIT was to find ways of cancelling out sources of background noise that could be mistaken for gravitational waves. “A passing truck or waves lapping against the ocean shore had to be excluded,” said Botner. Weiss pioneered ingenious ways of suspending mirrors that would capture the tiny movements caused by gravitational waves without any worldly disturbances.
Thorne, based at Caltech in Los Angeles, joined forces with Weiss to develop the interferometer itself, in collaboration with Scottish scientist, Ronald Drever, who passed away in March this year.
Barish took over the reins in 1994 as leader of LIGO and transformed what was a small research group of 40 into a major international collaboration of 1000 scientists.
Responding to the announcement today, Weiss said that the discovery would open new windows on sources of gravitational waves in the Universe. “We know about black holes and neutron stars, but we hope there are other phenomena we can see because of the gravitational waves they emit,” he said.