Bharat SainiLast Updated on November 7, 2017 by Bharat Saini
Nobel Prize in Physics 2017 has been awarded by the Royal Swedish Academy on Tuesday October 3, 2017 to Rainer Weiss, Barry C. Barish and Kip S. Thorne, three Americans members of the LIGO-Virgo detector collaboration, for their pioneering role in the detection of gravitational waves; “for decisive contributions to the LIGO detector and the observation of gravitational waves”. According to Nobel committee representative Göran K. Hansson in Stockholm, “This year’s prize is about a discovery that shook the world”. Albert Einstein predicted in his 1915 general theory of relativity that distortions in gravity would travel through space-time like a shock wave. It took nearly a century to confirm that these distortions exist, a feat that required huge contraptions in two locations to detect an ultra-tiny ripple in the fabric of space. One half of the prize went to Weiss born 1932 in Berlin, Germany and now a U.S. citizen, who is a physics professor at the Massachusetts Institute of Technology. And the other half went jointly to Barish born 1936 in Omaha, NE, USA, a Nebraska native, and Thorne born 1940 in Logan, Utah, USA. Both work at the California Institute of Technology. LIGO, the Laser Interferometer Gravitational-Wave Observatory, is a collaborative project with over one thousand researchers from more than twenty countries.
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 rotates 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.
Rainer Weiss had already analysed in the mid-1970s, the 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.
The universe’s gravitational waves were observed for the very first time On 14 September 2015. 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.
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 space time 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.
