Gravitational Waves: How Einstein's Spacetime Ripples Reveal the Secrets of the Universe

In 2015, after 50 years of searching, gravitational waves were detected for the first time and astronomy changed forever. In 2017 the project's leading scientists were awarded the Nobel Prize in Physics.

Astronomy has always depended on electromagnetic radiation: visible light, radio, X-rays and the rest. But gravitational waves -- ripples in the fabric of space and time predicted by  Einstein's general relativity -- can pass through barriers that stop light dead.

At the two LIGO observatories in the US, scientists developed incredibly sensitive detectors, capable of spotting a movement 100 times smaller than the nucleus of an atom. They recorded the ripples produced by two black holes spiraling into each other, setting spacetime quivering.

This was the first time black holes had ever been directly detected -- but it promises far more for the future of astronomy. One day we may be able to look back to the first seconds of the universe itself.