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.

The
crosshatched, warped sheet in the image above is a 2D
representation of the 3D space of our Solar System.


