We grow up believing that time is a steady, shared rhythm. One second is one second, whether you are sitting still or racing across the galaxy. But the universe does not share this democratic instinct. Because the speed of light remains absolutely constant no matter how fast you move, something else must give way to accommodate it. That something is time itself.

This episode explores how time dilation works, examining both the velocity-driven slowing of clocks described by special relativity and the gravitational time dilation of general relativity. We look at the concrete evidence that proves these effects are real, from the 1971 Hafele-Keating experiment flying atomic clocks around the world to the daily adjustments required to keep GPS satellites accurate. We also consider what happens to time near black holes, why subatomic muons surviv ...