B LIGO Back Online: Upgraded Detector to Spot Fainter Gravitational Waves

phinds
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From this morning's Economist briefing:

The Laser Interferometer Gravitational-Wave Observatory—the world’s most sensitive device for spotting gravitational waves—starts up again on Wednesday after a three-year hiatus for upgrades.

LIGO is designed to detect subtle ripples in space and time radiated out by cataclysmic cosmic events like colliding black holes and supernovae. The existence of these cosmic wiggles was predicted, over a century ago, by the mathematics of Albert Einstein’s general theory of relativity. But it was only confirmed when LIGO observed the waves in 2015. The upgrades to LIGO’s instruments have resulted in more sensitive detectors, capable of observing far fainter gravitational-wave events than before.

LIGO consists of two American detectors in the states of Louisiana and Washington. It will be joined on this run by Virgo and KAGRA, LIGO’s European and Japanese equivalents. Astrophysicists hope that the joint sensitivity of these observatories will be enough to detect waves from the universe’s earliest origins.
 
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phinds said:
starts up again on Wednesday after a three-year hiatus for upgrades.
Do you have a link to the upgrades that they did?
 
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