On the 3rd of October, the Royal Swedish Academy of Sciences announced the recipients of the Nobel Prize for physics. The Nobel Prize in Physics for 2017 was divided among three recipients: one half was awarded to Rainer Weiss, and the other half was split between Barry C. Barish and Kip S. Thorne for “for decisive contributions to the LIGO detector and the observation of gravitational waves.” All three scientists contributed key findings that led to the detection of gravitational waves within the fabric of time and space. The discoveries were made by the Laser Interferometer Gravitational Wave Observatory, more commonly known as LIGO. LIGO consists of twin ‘L-Shaped’ observatories based in Washington and Louisiana, as well as the Virgo detector in Italy. The process of detection comes after almost 45 years of cumulative investigation and the contributions of over one thousand researchers from 20 countries and has resulted in the detection of sought-after echoes from the collisions of two large entities, in this case: between two black holes.
So, what makes this discovery significant and what does it mean for the future of physics? LIGO is the brainchild of Rainer Weiss, who first hypothesised being able to identify the influence of a gravitational wave by using lasers in order to explain their existence to his students. The first official discovery of a gravitational wave occurred on the 14th of September 2015 – almost 100 years after Albert Einstein first predicted the existence of gravitational waves in his Theory of Relativity. As per Einstein’s theory, we now know that gravitational waves spread at the speed of light. This means that gravitational waves pass through all of us undetected, stretching every atom in our bodies before moving on. We are unable to sense these waves or feel them because they occur at such a low frequency. However, due to the sensitivity of the laser interferometers, they are able to measure a change “thousands of times smaller than an atomic nucleus” therefore successfully recording the ripples that were detected around the Earth’s atmosphere. The LIGO interferometers are designed to detect faint currents in the fabric of space and time as they move through the Earth’s part of space after being emitted by the collision of two black holes approximately 1.3 billion light-years away. Gravitational waves represent a brand new way of detecting the movement of mass generated by events such as the collisions of planets and black holes.
So far, other methods such as cosmic rays, neutrinos and electromagnetic radiation have been used to explore the universe, however by using gravitational waves “we now have a new way of understanding the universe by using gravity to investigate massive objects.” The significance of such a discovery will provide new insights into the nature of extreme gravity, and we now “witness the dawn of a new field: gravitational wave astronomy” (Nils Mårtensson, chair of the Nobel Committee for Physics).