Welcome to the Spacetime Emporium

This is a collection of information and resources for anyone interested in Einstein's Special and General Theories of Relativity. There are materials for a wide audience, from the general science reader to specialists in spacetime physics. You may create an account to personalize the Spacetime Emporium, organize resources, suggest additional material, or leave comments.

What is Relativity?

Physics happens in a dynamical, four-dimensional geometry called spacetime, where and when events occur. The mutual interactions between spacetime and matter/energy, and how they are perceived by different observers, is the essence of Relativity.