Nobel Prize for Physics awarded for detection of gravitational waves
Image credit: TT News Agency/Jessica Gow
The Nobel Prize for Physics 2017 has been awarded to a trio of US scientists who played key roles in the detection of gravitational waves. The effort involved a combination of cutting-edge experimental and theoretical work and more than 1,000 scientists around the globe.
The waves - often described as ripples in interwoven spacetime - were predicted by Albert Einstein on the basis on his theory of general relativity, along with the existence of black holes and other cosmological phenomena.
Gravitational waves are caused by colossal astronomical disturbances, such as the collision of black holes, causing ripples in spacetime to spread from the source at the speed of light.
Einstein himself believed that gravitational waves would never be observed due to the signal reaching Earth being far too weak for detection. A century passed between the prediction of gravitational waves and their detection at the Laser Interferometer Gravitational-Wave Observatory (Ligo) detectors.
Ligo is one of the largest scientific facilities on Earth, built by Massachusetts Institute of Technology (MIT) and California Institute of Technology (CalTech) specifically for the detection of gravitational waves. The twin observatories contain L-shaped systems containing multiple laser interferometers, which measure the displacement of light.
For such a catastrophic event – the rapid, violent circling and collision of two black holes – the signal the researchers were in search for was extremely subtle. The detectors were designed to capture a tiny disruption (of a thousandth the diameter of a proton) across a 4,000m laser beam.
The facility began searching for these tiny ripples in 2002, undergoing regular upgrades to increase its sensitivity. After “Advanced Ligo” came online in 2015, it took mere weeks to capture the signal of a gravitational wave, caused by the merging of two black holes 1.3 trillion light years from Earth.
“This is something completely new and different, opening up unseen worlds,” a statement by the Royal Swedish Academy of Sciences said. “A wealth of discoveries awaits those who succeed in capturing the waves and interpreting their message.”
The Academy stated that the signal was “already promising a revolution in astrophysics”.
The prize money will be awarded to Rainer Weiss, emeritus professor of physics at MIT, Kip Thorne, professor of theoretical physics at CalTech, and Barry Barish, emeritus professor of physics at CalTech.
Professor Weiss played an enormous role in the conception and construction of Ligo, having developed the technique on which it is based on. Professor Barish oversaw the project for many years as its executive director, and Professor Thorne, a theoretician, calculated how a trace of a gravitational wave would look in the detectors.
In a phone call thanking the Nobel committee, Professor Weiss said that: “I view this more as a thing that recognises the work of about 1,000 people, a really dedicated effort that’s been going on for - I hate to tell you - as long as 40 years.”
More than 1,000 other scientists around the world have been involved with the Ligo Scientific Collaboration, assisting in every stage from the design of the facility’s components to the analysis of data.
Ligo has since captured three more signals of gravitational waves: one in 2016 and two in 2017.