An international team of scientists have announced the first-ever direct detection of gravitational waves. The discovery opens a new astronomy window on the universe and confirms a major prediction of Albert Einstein’s 1915 general theory of relativity, and was made possible by British and German advances in technology.

“This is a monumental leap forward for physics and astrophysics – taking Einstein’s predictions and turning them into an entirely new way to sense some of the most fascinating objects in our Universe,” said Professor Sheila Rowan, Director of the University of Glasgow’s Institute for Gravitational Research, and a member of the discovery team.

Members of the IGR at the announcement of the detection in Glasgow.

The gravitational waves were detected on 14 September 2015 at 09:51 UK time by both LIGO (Laser Interferometer Gravitational-wave Observatory) detectors in Louisiana and Washington state in the US. They originated from two black holes, each around 30 times the mass of the Sun and located more than 1.3 billion light years from Earth, coalescing to form a single, even more massive black hole.

“Scientists have been looking for gravitational waves for decades, but we’ve only now been able to achieve the incredibly precise technologies needed to pick up these very, very faint echoes from across the Universe,” said Professor Karsten Danzmann, the Director of the Albert-Einstein-Institut in Hannover, and a member of the LIGO collaboration. “We tested these technologies at the joint German-UK GEO600 detector near Hannover before fitting them to LIGO.”

Professor Kenneth Strain is deputy director of the Institute for Gravitational Research at the University of Glasgow and principal investigator of the Advanced LIGO project team in the UK.
He said: "We’ve been involved with the LIGO and aLIGO initiatives from the beginning, and the simultaneous discovery of both evidence of gravitational waves and the collision of black holes is more than we ever could have hoped for. Many significant discoveries will be made as the field continues, which is enormously exciting. aLIGO’s discoveries will be immensely important in expanding our understanding of the universe, and we’re pleased and proud to be involved in this historic project.”

Professor Jim Hough, associate director of the University of Glasgow’s Institute for Gravitational Research, said:
"I began looking for evidence of gravitational waves in 1971, and I’ve spent my career since then involved in projects aiming to discover experimental proof of their existence. My immediate reaction when we heard about the first detection was a certain amount of delighted surprise, followed by great excitement when it became clear that the evidence was solid."

Dr Jonathan Gair from the School of Mathematics at the University of Edinburgh, said:
“2015 was a landmark year for gravitational wave science. Not only has LIGO directly detected gravitational waves from a merging black hole binary for the first time, but ESA successfully launched the LISA Pathfinder satellite in December, which will pave the way for a space-based gravitational wave detector within the next two decades. A fantastic way to celebrate the hundredth anniversary of the prediction of the existence of gravitational waves! This detection is a remarkable achievement of human endeavour, both in terms of the construction and operation of these amazingly sensitive detectors and in the analysis of the data they generate. I feel very privileged to have been involved with this work and the continued development of this new field. I am very excited to see what discoveries the next few years will yield, as we use these new observations to learn about exotic astrophysical systems, to put Einstein’s theory of relativity to the test in a new regime and perhaps also to see something completely unexpected!”

Dr Nicholas Lockerbie, Reader in Physics at the University of Strathclyde, said:
“The direct detection of gravitational waves marks the dawn of a new era in astronomy. I never expected to see this event in my lifetime. Gravity has now spoken to us, across vast tracts of the Universe. For the first time in mankind’s history, we have been able to hear it – and understand what it said. “This event – known as GW150914 – is evidence of a stunning black-hole-black-hole merger, lasting less than one second. However, its detection is the result of decades of international, scientific and technical collaboration, culminating in the matchless gravitational wave sensitivity of the Advanced LIGO detectors in the USA. I’m personally delighted and honoured that Strathclyde research and technology has also helped create the system behind this incredible discovery of gravitational waves.”