Astrophysicists Detect Black Holes and Neutron Stars Merging, This Time for Certain
The massive collisions occurred a billion years ago, sending out ripples in spacetime that eventually reached Earth.
Illustration: Carl Knox, OzGrav/Swinburne
A large collaboration of astrophysicists report they have made the first-ever confirmed detections of shockwaves produced by mergers between neutron stars and black holes. The detections, 10 days apart, represent two of these enormous cosmic unions.
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In January 2020, Earth quivered ever so slightly as shockwaves imperceptible to human senses passed through it. Those ripples were gravitational waves, perturbations in spacetime generated by all massive objects but only detectable from extremely huge events, like two black holes colliding. The waves were strong enough to be picked up by the Laser Interferometer Gravitational-Wave Observatory in Louisiana (the Washington branch of the instrument was offline at the time) and the similar Virgo experiment in Pisa, Italy. These experiments detect gravitational waves using a sensitive arrangement of mirrors and laser beams.