LMR-087 · Gravity & Time
Gravitational Waves
Ripples in spacetime, detected for the first time in 2015.
§ A first look
§ Depths
Six ways into the same idea — from bedtime story to chalkboard. No order required.
L1 · Crayon
Told like a bedtime story.
For a curious 10-year-old. No jargon. Just a picture in your head.
Drop a stone into a pond. Ripples spread out across the water in nice big circles. Now imagine two extremely heavy black holes far out in space, going round and round each other faster and faster until they smash together. They send out ripples too — not in water, but in space itself. The ripples travel outward across the universe and gently stretch and squish everything they pass through by a tiny, tiny amount. These ripples are called gravitational waves. We first managed to catch one with an extremely sensitive machine in 2015 and every physicist on Earth cried at once.
§ Strange but true
- 01Spacetime ripples. When two black holes collide, the wave shakes the whole universe — and us by a fraction of a proton's width.
- 02LIGO detected the first one in 2015, from a merger 1.3 billion years ago. We heard the sound of two voids meeting.
- 03Every gravitational-wave detector on Earth is measuring distance changes 10,000 times smaller than a proton.
§ From the field journal
Gravitational Waves
"Ripples in spacetime, detected for the first time in 2015."
— observed, sketched, not yet fully understood.
§ Nearby