If engineers hadn’t accounted for this one specific law of physics, your GPS would be wrong by 10 kilometers (6 miles) every single day. We tend to think GPS measures distance, when it actually, it measures time. Because light travels so fast, your phone calculates your exact position based on how long the signal took to arrive. But the universe tries to break that calculation and here is why... Special Relativity: Because satellites move so fast, their clocks tick slower. General Relativity: Because they are far from Earth’s gravity, their clocks tick faster. The Result: Gravity wins. Time in space runs 38 microseconds faster than time on Earth, every single day. That sounds small but light travels 300 meters in a single microsecond. If you multiply that error over 24 hours, the entire global navigation system becomes useless. 📚 Resources & Citations This is one of the most famous practical applications of relativity. Search this to learn more: The Paper: “Relativity in the Gl...