Astronomy and Astrophysics - An Introductory Survey, A lecture series by Prof. G. Srinivasan - 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. ABOUT THE LECTURE 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. ABOUT THE LECTURE SERIES This lecture series is organized by the Astronomical Society of India as a part of its Golden Jubilee celebrations. Aimed at undergraduate and graduate students, this series of talks by renowned astrophysicist and teacher, Prof G. Srinivasan, starts from the first principles of Physics and builds up the subject rigorously to the present state of our understanding. Series website: https://astron-soc.in/srini-ana The website hosts a question bank as well as a list of suggested reading for each lecture (prepared by Dr. Sushan Konar) ABOUT THE SPEAKER Professor G. Srinivasan In a research career spanning more than five decades, his interests have spanned many aspects of physics and astrophysics. He is a passionate teacher and has authored two outstanding Astronomy texts titled ‘What Are The Stars?’ and ‘Can Stars Find Peace?’ He is a Past President of the Astronomical Society of India, and a Past President of the Division on Space and High Energy Astrophysics of the International Astronomical Union. In his distinguished career he has worked at the University of Chicago, USA; the IBM Research Laboratory in Zurich, Switzerland; Chalmers University of Technology, Goteborg, Sweden; the Cavendish Laboratory, University of Cambridge, England and the Raman Research Institute, Bengaluru Follow us on social media at https://twitter.com/asipoec https://www.facebook.com/asi.poec/ This series is also supported by the IAU OAE Centre in India https://twitter.com/astro4edu_India https://www.facebook.com/OAE-Center-India-105698322030674