relativity together with quantum theory form the basis of modern physics. theory of relativity describes the composition of the universe and how it developed and it's not much like oh every day experience of the world time is relative and light doesn't travel in straight lines and only appears to fall from a tree. the theory says that gravity is the force of attraction but objects exert upon each other and that massive objects distort time and space and that was very new. einstein came up with the famous formula equals mc squared energy equals mass times the speed of light squared. it says that mass of energy are two forms of the same thing