than he was not entirely certain about these gravitational waves. He said they did not exist, then took it back; 20 years later, he changed his mind, again.
The Laser Interferometer Gravitational Wave Observatory (LIGO) launched its first experiment in 2000, using two detectors located in Livingston, Louisiana, and Hanford, Washington. But the detectors initially weren’t sensitive enough to find evidence of the miniscule disruptions caused by gravitational waves. After undergoing a series of upgrades from 2010-2015, LIGO’s technology went back online, with more powerful lasers and a better system of isolating the detectors from vibrations on the ground. At the time, scientists predicted they would be able to detect the first gravitational waves by 2016.
In fact, early on the morning of September 14, 2015, nearly as soon as the system was up and running, loud signals came through the detectors in both Louisiana and Washington. Each LIGO detector has an L-shaped antennawith two arms, each measuring some two-and-half miles long. At the end of each arm are mirrors of ultra-pure glass isolated from all
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