Rainer Weiss, a professor at the Massachusetts Institute of Technology, and Kip Thorne and Barry Barish, both of the California Institute of Technology, were awarded the Nobel Prize in Physics for the discovery of ripples in space-time known as gravitational waves, which were predicted by Albert Einstein a century ago but had never been directly seen.
In announcing the award, the Royal Swedish Academy called it “a discovery that shook the world.”
Gravitational waves describe the stretching and squeezing of space-time that occurs when massive objects accelerate.
The warping of space resulting from the merger of two black holes was initially picked up by the US Ligo laboratory in 2015 – the culmination of a decades-long quest.
These waves would stretch and compress space in orthogonal directions as they went by, the same way that sound waves compress air.
They had never been directly seen when Dr. Weiss and, independently, Ron Drever, then at the University of Glasgow, following work by others, suggested detecting the waves by using lasers to monitor the distance between a pair of mirrors.
The researchers calculated that a typical gravitational wave from out in space would change the distance between the mirrors by an almost imperceptible amount: one part in a billion trillion, less than the diameter of a proton.
The US Ligo and European Virgo laboratories were built to detect the very subtle signal produced by these waves.
Even though they are produced by colossal phenomena, such as black holes merging, Einstein himself thought the effect might simply be too small to register by technology.
But the three new laureates led the development of a laser-based system that could reach the sensitivity required to bag a detection.
- Gravitational waves are a prediction of the Theory of General Relativity
- It took decades to develop the technology to directly detect them
- They are ripples in the fabric of space-time generated by violent events
- Accelerating masses will produce waves that propagate at the speed of light
- Detectable sources ought to include merging black holes and neutron stars
- Ligo/Virgo fire lasers into long, L-shaped tunnels; the waves disturb the light
- Detecting the waves opens up the Universe to completely new investigations
Nonetheless, the Nobel trio’s contribution is also regarded as fundamental.
Weiss set out the strategy that would be needed to make a detection.
Thorne did much of the theoretical work that underpinned the quest.
And Barish, who took over as the second director of Ligo in 1994, is credited with driving through organisational reforms and technology choices that would ultimately prove pivotal in the mission’s success.
