Physics / Everyday

Your GPS Would Be Kilometres Wrong — If Not For Einstein

2026-07-17
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Every time you navigate, Einstein saves you.

Every time you check your location, your phone is quietly doing something remarkable. GPS satellites carry atomic clocks — some of the most precise timekeepers ever built. But those clocks don't tick at the same rate as clocks on the ground. Einstein showed us that speed and gravity both affect the passage of time, and satellites experience both differently to us. Leave that uncorrected, and your GPS position would drift by several kilometres within a single day. Not a small glitch — you'd be in the wrong town. So engineers baked Einstein's equations directly into the system. Every position fix your phone calculates has already accounted for relativistic time shifts. General relativity isn't some abstract theory from a textbook. It's running silently in your pocket, keeping you within metres of where you actually are. Follow Deep Field Vault for more of the universe hiding in plain sight.

GPS SATELLITES

  • carry atomic clocks
  • incredibly precise

THE PROBLEM

  • clocks in orbit
  • tick slightly faster
  • than clocks on Earth

WITHOUT A CORRECTION

  • your position drifts
  • kilometres per day

EINSTEIN'S FIX

  • relativity equations
  • built into the system

THE RESULT

  • accurate to metres
  • thanks to 1915 physics
Imagery: NASA (public domain) · View original on NASA ↗
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