This book continues our exploration of the most profound theory of science, Einstein’s General Theory of Relativity. We examine more carefully the properties of spacetime, the unity of space and time. We explore the major features of curvature, how to measure it, and how to reduce its complexity to finding distances between nearby points. We find a simple expression, 2M/r, which proves remarkably helpful as we explore the Schwarzchild metric, black holes, time dilation, and the expansion of the universe.
Readers will benefit from a prior reading of General Relativity 1: Newton & Einstein. In that first book on General Relativity in the Everyone’s Guide Series, we discussed the Principle of Relativity, which was first proposed by Galileo. We compared the key principles of Newton’s theory of gravity with Einstein’s theory. We discovered Einstein’s Equivalence Principle and why it was so important in the development of General Relativity. We discussed the gravitational bending of starlight that definitively distinguished Einstein’s theory from Newton’s, and discussed how Eddington succeeded in confirming General Relativity. We finally examined the three different effects of gravity, which each varies differently with distance: the acceleration of gravity, the tidal forces of gravity, and gravitational time dilation.
