Lecture 15 - General Theory of Relativity

The theory of gravitation due to Einstein is regarded as the most beautiful of all physics. This lecture is a rather condensed introduction to it.

This theory of gravitation due to Einstein is regarded as the most beautiful of all physical theories. Einstein realized that Newton’s theory of gravitation needed to be modified because it was inconsistent with his special theory of relativity. But, instead of taking care of this inconsistency in a straightforward way, he chose to be radical. He was unhappy with a ‘magical element’ in Newton’s theory, namely, Newton introduced two different masses, Inertial mass and Gravitational mass, only to set them equal to one another. This led Einstein to the revolutionary idea that gravity is not a force, but that the acceleration due to gravity is due to the curvature of space and time. In this lecture, I shall explain in simple language how Einstein was led to his new theory of gravity.