More than a billion years ago, two unbelievably massive black holes spun rapidly around each other before colliding and coalescing.
One had the mass of 36 suns, the other the mass of 29. These remnants of huge collapsed stars smashed together in a cataclysmic event forming a single 62-solar-mass black hole. The remaining three solar masses were dispersed throughout the universe at the speed of light in the form of gravitational waves, wobbling the very fabric of space-time.
And about 1.3 billion years after the event, these waves passed Earth, zipping by in just two-tenths of a second. 
Their detection on   September 14 by the Laser Interferometer Gravitational-Wave Observatory (LIGO) in the US has opened up a completely new window on the universe.
Until now we have only been able to look at the universe with our eyes - through the electromagnetic spectrum. Gravitational waves are a completely new spectrum by which we can observe our place in the cosmos.
"It's like being able to hear the universe for the first time," Professor David McClelland told Fairfax Media.
Professor McClelland is the director of the Centre for Gravitational Physics at the Australian National University. He also leads the Australian LIGO consortium, part of a global enterprise involving 1200 scientists in 15 countries.
If it hadn't been for Albert Einstein's theory of general relativity and the dedicated work of engineers and scientists that made LIGO a reality, we would never have witnessed this event.
And Australian scientists have played a critical role.
The machine that detected the waves, an interferometer, is a very sensitive laser. "The interferometers are four-kilometre-long systems using light to sense the separation between points," Professor McClelland said.
As the gravitational waves passed this detector they stretched the lasers by an infinitesimally small amount - 10,000 times shorter than the width of a proton. The lasers have to be very carefully calibrated with their reflecting mirrors to be able to detect this shift.
"The ANU, University of Western Australia and Adelaide University were all funded to put components and technologies into the [LIGO] interferometer," Professor McClelland said.
"The ANU developed a system which brings the mirrors in the interferometer into 'lock'.
"The University of Adelaide role has been to [develop] a correction system to adjust for mirror distortions. And UWA's expertise [was used] to ensure we avoid [mirror] instabilities.
"These contributions give the Australian consortium a stakeholder position in the LIGO project."
Researchers at these three universities, alongside others at Monash University, Melbourne University and Charles Sturt University, were also involved in analysing data coming from the LIGO project.
The CSIRO was contracted to polish and coat the laser mirrors at LIGO.
Why gravitational waves matter
Einstein was right (again!) The observation of gravitational waves confirms the final major prediction emerging from Albert Einstein's general theory of relativity.
Until this week astronomers had been able to look at the universe only through the electromagnetic spectrum including radio waves, optical light, X-rays, ultraviolet and infrared radiation.
Gravitational waves opens up a new spectrum for observing the universe, with access to previously invisible events such as black holes.
The discovery deepens our understanding of gravity, which will give us more information about the early stages of the universe and the very nature of the Big Bang itself.
A more complete understanding of gravity should be an important step towards unifying relativity with our understanding of quantum physics.