Two years ago, for the first time gravitational waves were detected in space, resulting from the collision of two black holes. This discovery fulfilled a prediction of Albert Einstein and opened up a whole new way to explore the heavens. This Tuesday, October 3, the three US scientists responsible for this achievement won the Nobel Prize 2017 in Physics. “The discovery is fantastic. A hundred years ago, Einstein realised that gravitational wave solutions existed in his general theory of relativity, “explains professor José Sande Lemos, president of the Multidisciplinary Centre for Astrophysics (CENTRA) at Técnico. “Researchers in the field of gravity have been dreaming of this discovery for more than fifty years. Finally it happened and was definitely recognised with the award of the Nobel Prize 2017 in Physics, “he reaffirmed.
“The three scientists are worthy of a Nobel prize”, says professor José Sande Lemos. In 1970, Rainer Weiss from MIT realised that a laser interferometer was the perfect detector and developed it. Kip Thorne from Caltech was the physicist who constantly developed the wave theory in the 1960’s. He joined Rainer Weiss in the construction of LIGO and, in the end of the 1990´s, Barry Barish led the Laboratory.
The highlight of this discovery was on 14th September 2015, which according to the president of CENTRA “it’s a historical moment” because it was when gravitational waves were detected for the first time. “The detected wave was traced in the final moments of the merger of two black holes”, explains the professor. Three other similar events occurred and were detected by LIGO: 26th December 2015, 4th January and 14th August 2017. We are now waiting for a possible announcement of detection of gravitational waves generated by two neutron stars. This detection will be extraordinary because it could be spotted by telescopes and gravitational wave detector at the same time”, says the president of CENTRA.
The Department of Physics and CENTRA have made important contributions through the publication of works on physics and astrophysics of black holes and neutron stars, organisation of several international conferences on this topic and training excellent PhD and MSc students. The research on black holes and gravitational waves at CENTRA has been coordinated by professors José Sande Lemos and Vítor Cardoso, the latter having won two European Research Council grants to deepen research in this area. “Our work is recognised abroad. The impact of scientific articles published in renowned magazines and the large number of most-cited papers are the proof of that”, highlights professor José Sande Lemos.
But how these discoveries can help us? We will have a much better understanding of our Universe, whether the theory of general relativity itself is correct even in situations as extreme as those involving black holes and neutron stars colliding at speeds close to the speed of light and we possibly know how many black holes and neutron stars exist per unit volume, among many other relevant things. The most curious thing is that we may be able to probe the first moments of the universe’s existence.