Clocks Run Faster At Altitude

It may sound like science fiction, but your head is aging infinitesimally faster than your feet. This bizarre reality stems from Albert Einstein's theory of general relativity, which describes gravity not as a force, but as a curvature in the fabric of spacetime. The more massive an object, the deeper the "gravity well" it creates. Time flows more slowly for objects deeper in this well, closer to the source of gravity. Therefore, moving away from the center of the Earth to a higher altitude means you are in a slightly shallower part of the gravity well, where the passage of time is a tiny fraction faster.

While this effect is imperceptibly small in our daily lives, it becomes crucial for modern technology. It was first confirmed experimentally in the 1970s using atomic clocks flown on airplanes, but its most significant real-world application is the Global Positioning System (GPS). The clocks on GPS satellites, orbiting far above the Earth in a weaker gravitational field, tick about 45 microseconds faster per day than clocks on the ground. Without constant correction for this "gravitational time dilation," the entire system would accumulate errors of several kilometers daily, rendering it useless for navigation.