Stephen Hawking has congratulated the team behind the detection of gravitational waves - direct evidence for one of Einstein's wildest predictions.
Gravitational waves, which were discovered by the Laser Interferometer Gravitational-Wave Observatory (LIGO) team, ripple through the universe, squeezing and stretching spacetime.
Physicists around the world detected signals of gravitational waves emanating from the collision of two massive black holes 1.5 billion light years away.
Posting on Facebook, Professor Hawking Said: "It is thrilling to see predictions I made over 40 years ago such as the black hole area and uniqueness theorems being observed within my lifetime."
Gravitational waves were first predicted by Einstein 100 years ago, but had previousy never been directly observed.
One senior British physiist described the breakthrough as the greatest scientific discovery so far this century.
Studying the waves could offer an insight into the early universe and possibly allow for new ways of observing the hidden regions of space.