听A COLLISION between two black holes was detected for the first time on 14 September 2015. It happened more than a billion years ago, but it generated ripples in the fabric of space-time, called gravitational waves, that were eventually detectable on Earth.
Researchers have since made countless discoveries about events in the universe using the Laser Interferometer Gravitational-Wave Observatory (LIGO), two widely separated gravitational-wave detectors based in the US. Now, they need your help to distinguish more signals from the noise.
Gravitational waves stretch and squeeze everything they pass through. These effects can be used to work out what caused the ripples in the first place. But the search for them can be hindered by glitches in the frequencies picked up by the gravitational-wave detectors, caused by background vibrations, other environmental interference or from the instruments themselves.
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More than 26,000 online volunteers with the , by labelling glitches in LIGO spectrograms, like the one pictured, based on the shapes they form. This helps researchers clean up the LIGO data, making it easier to identify true signals of high-energy astronomical events, such as colliding stars or black holes.
Visit . I quickly learned how to spot two common glitch patterns, known as 鈥渂lips鈥� and 鈥渨histles鈥�, using the online tutorial. Volunteers are helping LIGO scientists and engineers figure out the causes of the glitches in order to improve the detectors, says Gravity Spy team member of Information Studies in New York.
鈥淗aving a collection of the same kind of glitch is useful to guide the search for what else is going on in the detector at the same time that might have caused that particular kind of glitch,鈥� says Crowston. His team also uses the data from volunteers to train AI models to detect and categorise glitches.
If you spot a strange pattern that doesn鈥檛 fit into one of the predefined categories, you might have discovered a new type of glitch. 鈥淢ore advanced volunteers identify novel classes of glitches; things that they鈥檝e noticed because they have looked at so much data that the LIGO scientists don鈥檛 know about,鈥� says Crowston.
Meanwhile, scientists continue to make exciting new discoveries of ripple-generating events in the universe. Signals detected by a LIGO detector and a similar observatory called Virgo in Italy in early 2020 were found to have originated from a black hole swallowing a neutron star more than 900 million light years away from Earth.
Learn more, and get involved, at Gravity Spy.
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