This article is great but the references to gravitational waves as if they were an observed fact (in 1972) was mystifying to me. It led me down a rabbit hole to

This article is great but the references to gravitational waves as if they were an observed fact (in 1972) was mystifying to me. It led me down a rabbit hole to Joe Weber, who is name-checked at the end of the Penrose article. A Fleeting Detection of Gravitational Waves https://physics.aps.org/story/v16/st19 https://physics.aps.org/story/v16/st19 Gravitational wave blues https://aeon.co/essays/how-joe-weber-s-gravity-ripples-turned-out-to-be-all-noise https://aeon.co/essays/how-joe-weber-s-gravity-ripples-turne...