###

Sciences

*Here's some basic background covering how mathematical models of
space and time have evolved since ancient times, from the Pythagorean
Rule to Newtonian mechanics, Special Relativity and General Relativity.*

What is spacetime?

Why was Einstein's Special
Theory of Relativity needed?

How does Einstein's Special
Theory of Relativity work?

What is "causality" and what does it have to
do with time travel?

What is gravity?

What is Einstein's General Theory
of Relativity?

Observations of spacetime bending light

*Flatland with gravity - how does that work? In one
time and two space dimensions, the Einstein equation is almost too
simple, but the results are not! See how spacetime curvature warps
light cones, creates ambiguities in causal boundaries, and even allows
at least a mathematical possibility for time travel.*

*Space / Time in 2 dimensions*