IOP hails detection of gravitational waves from collision of neutron stars

16 October 2017

The IOP has hailed today’s announcement that gravitational waves have been detected from the collision of two neutron stars – an event that was also observable in visible light.

IOP hails detection of gravitational waves from collision of neutron stars
NSF/LIGO

UK scientists representing the Laser Interferometer Gravitational-Wave Observatory (LIGO), Virgo, and some 70 observatories worldwide delivered details of the new findings in the study of extreme events in the cosmos at a briefing at the Royal Society in London, held simultaneously with similar events in Washington and Munich.

Today’s ground-breaking news represents a major step forward in astronomy and astrophysics and is providing astrophysicists with an unprecedented wealth of data about the universe, 130 million years after the stars met their violent end.

On 17 August this year, a gravitational wave signal was picked up by the LIGO detectors in the US. The signal came from the collision of two neutron stars – the densest stars known to exist. In their final moments of orbiting each other, as their separation shrunk to within a few hundred miles, the stars spiralled ever faster and closer together, stretching and distorting spacetime around them and giving off energy in the form of powerful gravitational waves.

These findings – the first time that physicists have detected gravitational waves from an event that was also observable in visible light – provide further confirmation for Einstein’s general theory of relativity, which predicts that gravitational waves should travel at the speed of light.

Delivering the findings in the UK were Lord Rees, Astronomer Royal, Dr John Veitch, University of Glasgow, Dr Kate Maguire, Queen’s University Belfast, Dr Phil Evans, University of Leicester, Dr Will Farr, University of Birmingham and Dr Francesco Pannarale Greco of Cardiff University.

Professor Paul Hardaker, chief executive officer at the IOP, said: “This is just such an exciting discovery and reinforces why this year’s Nobel Prize in Physics for those working on the detection of gravitational waves was very timely and well deserved.

“For as long as we have had astronomy we have used light, in one form or another, to observe the universe. Using gravity itself has opened up a whole new window on our universe, and with this discovery we have been able to combine these two methods – and the result is quite remarkable.

“It is already allowing us to explore more deeply the fundamentals of how our universe works, like how stars and galaxies form and how fast the universe is accelerating. What an amazing set of observations and, excitingly, I am sure there is much more to come.”

Professor Sheila Rowan, director of the Institute for Gravitational Research (IGR) at the University of Glasgow, said: “This year Nature has given us the most dazzling gift. The first gravitational wave signals from colliding neutron stars are a key that has allowed us to unlock the door to answer several longstanding mysteries.

“One of these, tackled by working in partnership with colleagues whose telescopes observed the light, radio and other signals form this violent merger, is the puzzle of where some of the gold and other heavy elements in the cosmos come from. We now believe that the violent collision of neutron stars could be a gold factory.

“With this binary neutron star detection, we’ve been able to both look and ‘listen’ for the first time and the results are quite extraordinary.”

Dr John Veitch, a research fellow at the IGR, added: “Unlike black holes, neutron stars are made of matter, with an accompanying mass that we can measure – in this case, we’ve learned that the signal originated from neutron stars with a mass roughly equivalent to our sun but compressed way down into a space about the size of the city of Glasgow.”

Professor Martin Hendry, head of the School of Physics and Astronomy, concluded: “To measure the expansion rate of the universe using the gravitational waves from colliding neutron stars has been my burning ambition for nearly 20 years. It’s beyond my wildest hopes that we would be able to make this measurement so soon – with such exquisite observations not just in gravitational waves but across the entire electromagnetic spectrum.”

Gravitational waves were officially confirmed for the first time in February 2016, when LIGO announced that it had detected the phenomenon, caused by a collision between two black holes. Since then, gravitational waves have been detected three more times. These findings have opened up a new field of gravitational-wave astronomy – with UK physicists playing a leading role in the key technological and computing advances that have enabled these historic detections. The 2017 Nobel Prize in Physics was awarded to the team behind the gravitational waves breakthrough.