The 2017 Nobel prize in Physics has been awarded to Rainer Weiss, Barry C. Barish and Kip S. Thorne “for decisive contributions to the LIGO detector and the observation of gravitational waves”.
It is, frankly, difficult to find something original to say about the detection of gravitational waves that hasn't been said already. The technological feat of measuring fluctuations in the fabric of spacetime less than one-thousandth the width of an atomic nucleus is quite simply astonishing. The scientific achievement represented by the confirmation of a century-old prediction by Albert Einstein is unique. And the collaborative effort that made the discovery possible — the Laser Interferometer Gravitational-Wave Observatory (LIGO) — is inspiring.
Rainer Weiss and Kip Thorne were, along with the late Ronald Drever, founders of the project that eventually became known as LIGO. In the 1960s, Thorne, a black hole expert, had come to believe that his objects of interest should be detectable as gravitational waves. Separately, and inspired by previous proposals, Weiss came up with the first calculations detailing how an interferometer could be used to detect them in 1972. By the early 1980s they had joined forces with Drever to work on the giant twin detectors that would eventually be set up in Livingston, Louisiana, and Hanford, Washington. This not only required scientific and technological vision, but also political skill and pragmatism to get the project funded by the US National Science Foundation (and eventually by an international consortium of funding agencies).
Barry Barish, who was the director of LIGO from 1997 to 2005, is widely credited with transforming it into a 'big physics' collaboration, and providing the organizational structure required to ensure it worked. Of course, the passion, skill and dedication of the thousand or so scientists that worked on LIGO over many decades was essential to its scientific success — an aspect all three laureates and the Nobel committee itself have been keen to stress.
The discovery of GW150914 (pictured), the echo from a collision of two black holes about 1.3 billion light years away, caused a media sensation when it was announced in February last year. It was, rightly, heralded as the dawn of a revolution in astrophysics.
Last month we received a spectacular demonstration that talk of a new era of gravitational astronomy was no exaggeration. Cued by detections at LIGO and Virgo, an interferometer based in Pisa, Italy, more than 70 teams of researchers working at different telescopes around the world confirmed the observation of a neutron-star merger. A slew of papers published on 16 October reported the electromagnetic counterpart to the gravitational-wave detection.
These observations simultaneously solve a number of outstanding problems, including the origin of the heavier elements of the periodic table. It is difficult to imagine that this is the last time that ripples of spacetime will reach Stockholm.