Question

please explain theory of relativity in detail

Answer 1

In detail... This website wont allow me to post that much information. I'll give you this: The first is the Special Theory of Relativity, which essentially deals with the question of whether rest and motion are relative or absolute, and with the consequences of Einstein’s conjecture that they are relative.
The second is the General Theory of Relativity, which primarily applies to particles as they accelerate, particularly due to gravitation, and acts as a radical revision of Newton’s theory, predicting important new results for fast-moving and/or very massive bodies.