Three US scientists share Physics Nobel for work on gravitational waves

A day after three US scientists won the Nobel Prize for Medicine or physiology, three other US scientists - Rainer Weiss, Barry C Barish, and Kip S Thorne – all colleagues at the LIGO project - have won the Nobel Prize for Physics

The Laser Interferometer Gravitational-Wave Observatory (LIGO) is run by the California Institute of Technology and the Massachusetts Institute of Technology.

The three have jointly won the 2017 Nobel Prize in physics, for their contributions to work that led to the observation of gravitational waves - something that happened for the first time in 2015 at the LIGO project.

The Royal Swedish Academy of Sciences has decided to award the Nobel Prize in Physics 2017 with one half to Rainer Weiss and the other half jointly to Barry C Barish and Kip S Thorne "for decisive contributions to the LIGO detector and the observation of gravitational waves"

On 14 September 2015, the universe's gravitational waves were observed for the very first time. The waves, which were predicted by Albert Einstein a hundred years ago, came from a collision between two black holes. It took 1.3 billion years for the waves to arrive at the LIGO detector in the USA.

The signal was extremely weak when it reached Earth, but is already promising a revolution in astrophysics. Gravitational waves are an entirely new way of observing the most violent events in space and testing the limits of our knowledge.

LIGO, the Laser Interferometer Gravitational-Wave Observatory, is a collaborative project with over one thousand researchers from more than 20 countries.

Pioneers Rainer Weiss and Kip S Thorne, together with Barry C Barish, the scientist and leader who brought the project to completion, ensured that four decades of effort led to gravitational waves finally being observed.

In the mid-1970s, Rainer Weiss had already analysed possible sources of background noise that would disturb measurements, and had also designed a detector, a laser-based interferometer, which would overcome this noise. Early on, both Kip Thorne and Rainer Weiss were firmly convinced that gravitational waves could be detected and bring about a revolution in our knowledge of the universe.

Gravitational waves spread at the speed of light, filling the universe, as Albert Einstein described in his general theory of relativity. They are always created when a mass accelerates, like when an ice-skater pirouettes or a pair of black holes rotate around each other. Einstein was convinced it would never be possible to measure them. The LIGO project's achievement was using a pair of gigantic laser interferometers to measure a change thousands of times smaller than an atomic nucleus, as the gravitational wave passed the Earth.

''So far all sorts of electromagnetic radiation and particles, such as cosmic rays or neutrinos, have been used to explore the universe. However, gravitational waves are direct testimony to disruptions in spacetime itself. This is something completely new and different, opening up unseen worlds. A wealth of discoveries awaits those who succeed in capturing the waves and interpreting their message.'' The Nobel Prize Committee said in a release.

Rainer Weiss was born on 29 September 1932 in Berlin, Germany He was educated at the Massachusetts Institute of Technology (1962). He had won the Gruber Prize in Cosmology. It was he who pioneered the laser interferometric gravitational wave observation.

Barry C Barish was born in 1936 in Omaha, Nebraska, US. He received his PhD in from University of California, Berkeley, California, US, in 1962. He was Linde Professor of Physics at the California Institute of Technology, Pasadena, California.

Kip S Thorne was born in 1940 in Logan, Utah, US. He received his Ph.D from Princeton University, New Jersey, US in 1965. He was Feynman Professor of Theoretical Physics at the California Institute of Technology, Pasadena, California