Over a billion years ago two black holes collided in a distant galaxy, which sent ripples of distorted geometry through spacetime itself. These ripples travelled through many galaxies, including our own, and reached our planet just 10 and a half years ago, momentarily squishing it by a fraction of the size of an atom. Humans were lucky to have just built an instrument (LIGO) sensitive enough to feel this squish, causing this to be the first gravitational wave to be detected, a big event in science.
I sometimes think about how many planets this must have happened to before us and will surely happen to in the future. Gravity waves sweep across our galaxy all the time. If by any chance the Galaxy is teeming with intelligent life, there could be waves of aliens having their own LIGO moments riding the fronts of those gravity waves. I think that's really cool.
The Universe helps its curious inhabitants discover itself.
