Einstein did indeed come up with several theories to that effect. But again, I ask for specific experiments demontrating that they have been proven true
Ever hear of the Global Positioning System (GPS)? The fact that it works proves that General Relativity (GR) is true (insofar as anything is ever proven in science).
GPS satellites contain extremely accurate clocks ... but they are purposefully manufactured on Earth to be inaccurate, in a very specific way that is predicted by GR. When they go into orbit the clocks change, because they are moving and they are higher in the Earth's gravitational field, and they become as accurate as required.
If we didn't apply the GR correction when manufacturing the clocks, they wouldn't be accurate enough when the satellite is orbiting.
See
General relativity in the global positioning system and
Relativity in the Global Positioning System (the latter is very technical).
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