Earth is surfing on a sea of gravitational waves
Colliding galaxies create huge distortions in the space-time continuum that can be detected on Earth in the form of gravitational waves disrupting signals from distant pulsars. Much of this was known before this week – the existence of pulsars and gravitational waves, for instance – but the bigger picture of “a universe that looks like a choppy sea” has been put together in five astrophysics papers published simultaneously in the Astrophysical Journal Letters. The papers measure the effect of gravitational waves over a long period and appear to confirm Einstein’s hunch that the fabric of space and time is rumpled by big cosmic events. The biggest imaginable are collisions of pairs of galaxies centred on supermassive black holes. As the black holes orbit each other they emit gravitational waves powerful enough to disrupt otherwise regular patterns of signals from pulsars – but at such low frequencies that they took a wide array of earthly telescopes 15 years to detect.
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