Which achievement of einstein does
gps owe its ability to function and why?

Einstein considered himself agnostic not atheist . But GPS systems owe a debt of gratitude to Einstein and his thought experiments, without which they would not exist at all. The highly precise clocks have oscillators that function not on springs or pendulums, but atoms. Idk if this is the right answer but hope it helped n I copied it isn’t my answer cuz I haven’t had that question