On 11 February 2016, it was announced by the Laser Interferometer Gravitational-Wave Observatory (LIGO) collaboration that gravitational waves had been discovered, finally confirming a century old prediction. This was very exciting, and the story was big news, making the front page of national newspapers and magazines, with even President Obama tweeting about it. The history of gravitational waves up to their discovery is rather interesting, so I thought I’d share some of it here.
Take two phone books and interleave all their pages one by one. Now try and pull them apart by their spines. Impossible, right? You may have seen this trick before: it’s used as a classic example of the extreme power of friction. There’s some great videos online of two trucks each tethered to one of the books, trying and failing to pull them apart. You can even lift a car with a crane by using a pair of phone books instead of a strap.