In this file photo dated Thursday, Feb. 11, 2016, Laser Interferometer Gravitational-Wave Observatory (LIGO) Co-Founder Rainer Weiss speaks during a news conference at the National Press Club in Washington, as it is announced that scientists have finally detected gravitational waves. Photo: Andrew Harnik, AP File

Many of the Nobel Prizes are bestowed upon scientists, thinkers and writers only decades after their biggest contributions to their respective fields. The Medicine Prize, given yesterday, was given to three scientists for work mostly completed in the 1980s and 1990s.

But this year’s Nobel in Physics is a bit different. The three American physicists who garnered the Prize this morning (ages 85, 81, and 77) made their arguably biggest contribution just two years ago.

The discovery of gravitational waves, the ripples in space-time that proved some of the century-old theories of Albert Einstein, was the work that earned Rainer Weiss, Barry C. Barish, and Kip S. Thorne the Prize this year.

Gravitational waves were first detected at the Laser Interferometer Gravitational-Wave Observatory detectors in Louisiana and Washington state on Sept. 14, 2015. The announcement was made in February 2016, just a few months later. The fourth detection of such waves, based on the changes to the direction of lasers bouncing back and forth between mirrors at the massive facilities, was made on Aug. 14.

Weiss, of the Massachusetts Institute of Technology, first designed the laser interferometer, and refined the performance thresholds for the evolving tool. Thorne, now of the California Institute of Technology, was an early supporter and collaborator, and was the hand that predicted what the signals would “sound” like. Barish, now also at Caltech, was hailed today for leading the LIGO project to its ultimate completion by being a “scientific leader” in making the project happen, according to Nils Martensson, the acting chairman of this year’s Nobel Committee for Physics.

“This year’s Nobel laureates represent – in an excellent way – the diverse competences needed for LIGO success,” said Martensson, in this morning announcement. “Without them, the discovery would not have happened.”

The detection, Martensson added, was a “truly remarkable achievement which crowns almost 50 years of experimental efforts.”

Weiss told the press conference by phone he had finally dressed since getting the early call, and took a few questions from the international press corps.

“There’s a huge amount of things to find out in the universe that radiate gravitational waves,” the physicist explained. “The black holes are probably the strongest source, but there are many, many others.”

But the trio were not alone in making the work happen, Weiss said.

Hundreds of scientists and engineers were involved in the work leading up to the 2015 detection, Martensson added. Currently, the LIGO-Virgo collaboration has grown to 1,000 members on five continents, the Nobel committee explained in awarding the prize.

“They were so humbled and very, very, gratified they were awarded the Prize, but also – all three of them – mentioned: one, that they were happy they were not alone; and two, that we should stress the role of the collaboration at the press conference, and even at the award ceremony,” said Olga Botner, a member of the Nobel committee, and herself a professor of experimental elementary particle physics.

Weiss will get half the 9 million Swedish krona, while Barish and Throne will split the other half of the award.