MADRID (AP) — Astrophysicists whose work led to the ground-breaking detection of cosmic gravitational waves first predicted by Einstein have been awarded Spain's Princess of Asturias 2017 scientific research.

Prize organizers said Wednesday the award went to American physicians Rainer Weiss, Kip Thorne and Barry Barish and to the LIGO Scientific Collaboration group of international astrophysicists.

Physicists used LIGO instruments in 2015 to detect a gravitational wave generated by two black holes colliding 1.3 billion light-years from Earth. The discovery was seen as a eureka-type moment in observing the universe.

Weiss, Thorne and late physician Ronald Drever founded LIGO — Laser Interferometer Gravitational-Wave Observatory — in the 1980s and Barish opened the group up to international members in 1997.

The award is one of eight Asturias prizes for different fields granted yearly.