Science tends to work in two directions: we both observe things and then try to explain what we observe, like with the IceCube results, and we also make predictions about the universe and look for evidence of those predictions. Some theories are harder to believe than others, even with a profundity of evidence, and these are the ones I get the most excited to see proved true once again. From relativity getting tested over to quantum mechanics getting tested over and over, it is just pleasing when reality says “I know I’m weird, but I’m predictably weird.” The LIGO experiments have just allowed one of these amazing tests of quantum mechanics to take place. 

It had been predicted that objects the size of LIGO’s 40-kg mirrors would jiggle at the smallest level due to the constant popping in and out of existence of virtual particles. The amount that it moves is a mind-blowingly small amount: just 10^-20 of a meter. Researcher Lee McCuller uses the following analogy: A hydrogen atom is 10^-10 meters, so this displacement of the mirrors is to a hydrogen atom what a hydrogen atom is to us. Thanks to the extraordinary preciseness needed to measure gravitational waves, this amount of noise is apparent in the LIGO data, and nicely matches predictions, showing once again that with science we can understand things that our day-to-day experience never prepared us for.

More information

MIT News release 

“Quantum correlations between light and the kilogram-mass mirrors of LIGO,” Haocun Yu et al., 2020 July 1, Nature