Question

what is theory of relativity?

Answer 1

Albert Einstein's theory of relativity is actually two separate theories: hisspecial theory of relativity, postulated in the 1905 paper,The Electrodynamicsof Moving Bodiesand histheory of general relativity, an expansion of the earlier theory, published asThe Foundation of the General Theory of Relativityin 1916.Einstein sought to explain situations in which Newtonian physics might fail to deal successfully with phenomena, and in so doing proposed revolutionary changes in human concepts oftime,spaceandgravity.