Image copyright Caltech/MIT/LIGO Lab Image caption The Ligo detector laboratory in Louisiana

Scientists at Cardiff University played a key role in one of the "biggest breakthrough in physics for the last 100 years", BBC Wales can reveal.

Theoretical models developed by researchers were used to verify the detection of gravitational waves.

Predicted by Albert Einstein in his famous Theory of General Relativity the tiny ripples in space-time offer a new way of exploring the universe.

A super-computer at the university was used to examine data.

Media conferences were being held simultaneously in Washington, London and Cardiff as rumours the waves had finally been detected were confirmed.

The US-based Ligo (Laser Interferometer Gravitational Wave Observatory) Project has been searching for evidence of their existence since 1992.

900 scientists worldwide were involved in the experiment, centred around observatories in Washington and Louisiana.

Sensitive detectors, searching for signals from space, were upgraded in 2015.

Media playback is unsupported on your device Media caption Astrophysicist Deepali Lodhia explains what the discovery means

Meanwhile a powerful supercomputer at Cardiff University's School of Physics and Astronomy was used to comb through the gathered data.

Researchers at the university's Gravitational Physics Group used computer simulations of black-hole collisions to produce theoretical models, confirming the signals detected by Ligo were in fact gravitational waves.

They are predicted to result from extreme cosmic events, such as the merger of black holes and the explosive demise of giant stars.

Scientists say being able to sense them will usher in a new era of astronomy.

They will no longer have to depend on traditional light telescopes to see and understand phenomena in space.

Speaking exclusively to BBC Wales ahead of the announcement the team at Cardiff told of their excitement.

Dr Patrick Sutton, head of the Gravitational Physics Group said the university had been involved in the Ligo project since the experiment's founding.

"Our speciality here is in modelling the signals that would come from the collision of black holes and then sifting the data from the detectors to find these very weak signals hidden in the data."

'Secret'

"I think it's a moment for Wales and for Cardiff University. We can be proud that we've contributed to opening up a whole new area of astronomy, a major achievement in science and verifying the last great prediction of Einstein's theories."

Dr Stephen Fairhurst said it was one of the biggest discoveries in physics and something the team had been dreaming of.

"We've known for five months and have been keeping it a secret. Now we can actually tell people and it's starting to sink in. It's a fantastic moment and there's a good chance this experiment will win a Nobel prize."

The team's work has also led to the first direct observation of binary black holes, a system consisting of two black holes in close orbit around each other.

Image caption A computer visualisation of black holes orbiting each other, as detected by gravitational waves

The explosive collision and merging of these black holes over a billion years ago in a galaxy more than a billion light years from Earth produced the gravitational waves detected by the Ligo project's sensors.

It is the most powerful event ever observed in the universe.

Prof Mark Hannam lead the work of producing the theoretical models predicting what the waves emitted from collision should look like.

"Actually seeing the signal that we had been calculating coming out of the data was incredible."

"It's a bit like learning a foreign language - you practice and practice and then you travel abroad and suddenly things happen - it's just amazing."

Prof B S Sathyaprakash, director of Cardiff University's Data Innovation Institute said it was a "very momentous occasion" for the university.

"But this is just the start, because it opens up a new chapter in human understanding of space. It gives us a view of the universe when it was very young and dynamic - and that's what we will begin to detect over the course of time."