GPS Relativity
Satellites move at high speed far above Earth, where gravity is weaker. According to Einstein's general theory of relativity, weaker gravity makes clocks run faster. According to his special theory of relativity, fast motion makes clocks run slower. It's hard to imagine, but time passes at a different rate aboard a satellite than on Earth! GPS Relativity (2026) shows live GPS or GLONASS satellites, depending on the receiver's current mode, and the calculated relativistic clock effects for the selected satellite.