E7.3 - GPS Versus Einstein

In this episode of the Ask Us Whatever Relativity series, host Joe Sorge shows that the GPS navigation system would fail if the atomic clocks aboard GPS satellites were synchronized with Einstein’s method. Such clocks must be adjusted to compensate for the relativistic effects of gravity and speed on time dilation, but they cannot be synchronized using Einstein synchronization. Joe walks us through the Sagnac Effect and the differences between Einstein clock synchronization and the absolute synchronization method relied upon by GPS systems and by coordinate universal time (UTC) atomic clocks. Joe makes clear that in the reference frame of the Earth, light speed is NOT constant if measured with atomic clocks that have been absolutely synchronized, and that Einstein synchronization creates the illusion of constant light speed in moving inertial reference frames; whereas absolute clock synchronization reveals this illusion.

#Veritasium #PBSSpaceTime #QuantaMagazine #Einstein #SagnacEffect #LightSpeed

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