The waves they recorded came from the collision of two black holes, using the world's most sophisticated detector, which Australian scientists helped create.
A century of speculation, 50 years of trial and error, and more than 25 years perfecting the world's most sophisticated detector has paid off.
Scientists have had their first glimpse of gravitational waves.
Executive Director of the Lazer Interferometer Gravitational Wave Observatory, or LIGO, David Reitze, announced the breakthrough.
"Ladies and gentlemen, we have detected gravitational waves. We did it! So these gravitational waves were produced by two colliding black holes that came together, merged to form a single black hole about 1.3 billion years ago. The signal had a very specific characteristic of, as time went forward, the frequency went up. And what was amazing about this signal is that it's exactly what you would expect, what Einstein's theory of general relativity would predict for two big massive objects like black holes, in spiralling and merging together."
Gravitational waves are created when there's a seismic event in the universe - like two black holes colliding.
The waves of energy from the event ripple across the galaxy at the speed of light, squeezing and stretching space as they go.
When they pass through the Earth there's a very tiny jolt which has been, until now, incredibly hard to detect.
Scientists recorded the sound of the wave but had to change the frequency of the playback so humans could hear it.
They also had to loop the recording - repeat it - as it's such a tiny sound.
Gravitational waves were hypothesized in Abert Einstein's General Theory of Relativity a century ago.
This announcment is further confirmation that he was right.
But it took decades of theoretical and practical work by an international network of more than 1,000 scientists and engineers to make the discovery.
Australian National University Professor David McClelland says the ANU, the University of Western Australia and University of Adelaide helped build crucial components of the LIGO detectors used to find the gravitational waves.
"They're massive instruments. They're four kilometre-long, L-shaped devices which laser beams are propogated up and down in these vacuum systems, and we're measuring the time it takes the laser to travel from one end of the system and back, and that timing tell us about whether a gravitational wave has passed through."
Scientists helped develop the mirrors, camera, monitoring and data retrieval systems that make up the LIGO detectors.
Professor McClelland says it will be used to identify new aspects of the universe.
"Everything we know about the universe is from electromagnetic waves, or light waves. 70 per cent of the universe doesn't emit light, so 70 per cent of the universe is dark. Gravitational waves come from the very distortions of the fabric of the universe. They're a completely new sense, a completely new way to listen to the universe."
Scientists say they can now look much deeper into space and further back in time - eventually as far back as the Big Bang.
Professor Stephen Hawking has told the BBC the fusion of two black holes had been predicted, but never observed.
"Gravitational waves provide a completely new way of looking at the universe. The ability to detect them has the potential to revolutionise astronomy. This discovery is the first detection of the black hole by an early system, and the first observation of black holes merging."
Professor Reitze, from LIGO, says the discovery is a leap forward as important as Galileo Galilei's.
"400 years ago Galileo turned a telescope to the sky and opened the era of modern observational astronomy. I think we're doing something equally important here today. I think we're opening a window on the universe, the window of gravitational wave astronomy."
Professor McClelland says it's a once in a lifetime event - with exciting potential for the future.
"We've developed a new sense for which we can study the universe. And what we're going to find in that dark side of the universe - that's what the future's about. The announcement today, is just the beginning."
