In 2010, physicists at the National Institute of Standards and Technology placed two of the world’s most precise atomic clocks side by side — and then raised one of them by exactly one foot. They weren’t the same anymore. The higher clock ticked faster. Not in theory, not as a rounding error — measurably, verifiably, by an amount that accumulates to 90 nanoseconds over a human lifetime. This is gravitational time dilation explained at the most intimate scale imaginable: right now, the top of your body is aging slightly faster than the bottom. Your feet are a little younger than your head. Einstein predicted this in 1907. It took us a century to build clocks precise enough to prove it on a staircase. Gravitational Time Dilation Explained: Why Gravity Bends Time In Einstein general relativity, time and gravity are not separate forces — they are expressions of the same curved…