Keep in mind Duronto Sohag there are *two theories
- Special Relativity
- General Relativity
Special has to do with time ticking at different paces in different inertial reference frames based on one’s velocity.
General is all about how mass itself bends spacetime and creates gravity…a big part of this is the “equivalence principle”…which einstein recognized was the fact that something in free fall is identical to something accelerating…which led him to believe that gravity…well see here
In the physics of general relativity, the equivalence principle is any of several related concepts dealing with the equivalence of gravitational and inertial mass, and to Albert Einstein’s observation that the gravitational “force” as experienced locally while standing on a massive body (such as the Earth) is actually the same as the pseudo-force experienced by an observer in a non-inertial (accelerated) frame of reference.