The Absurd Lengths Scientists Used to Detect Gravitational Waves

Veritasium host Derek Muller visits physicist Rana X Adhikari to better understand the absurd lengths scientists at the Laser Interferometer Gravitational-Wave Observatory (LIGO) went to to detect gravitational waves. The discovery was made in early 2016, confirming Einstein’s prediction about the waves made 100 years earlier, but it took incredible feats of engineering and precision to be able to make the observation.

When scientists want one megawatt of laser power, it’s not just for fun (though I’m sure it’s that too), it’s because the fluctuations in the number of photons is proportional to their square root, making more powerful beams less noisy (as a fraction of their total). The smoothest mirrors were created not for aesthetic joy but because when you’re trying to measure wiggles that are a fraction the width of a proton, a rough mirror surface simply won’t do.