A new gravitational-wave detection has excited astronomers

The 2017LIGOH Nobel prize for physics for the confirmation of a prediction made 101 years earlier. In 1916 Albert Einstein, whose theories of special and general relativity revolutionised scientists’ understanding of physics at the scale of stars and galaxies, predicted that, in certain circumstances, the fabric of the universe itself should wobble and flex.The culprits are gravitational waves, which are to gravity as radio waves or visible light are to electromagnetism. In 2015 gravitational waves were directly observed for the first time. , an American observatory based in Washington state in that country’s north-west, and Louisiana in the south-east, detected waves produced by a pair of colliding black holes, each about 30 times the mass of the sun. That produced ripples in spacetime with a frequency of about 150z, or cycles per second, and a wavelength of around 2,000km.