A decent explanation of the concept of time as the fourth dimension. The author discusses Einstein's theory of special relativity and the idea of space-time.

This article provides a quick introduction to special relativity.

A historical approach to special relativity, giving all the events and names in the history of discovery of special relativity. Many links to these individuals.

In this first lesson of a three-part series on space-time, hilarious hosts Andrew Pontzen and Tom Whyntie go through the basics of space and time individually, and use a flip book to illustrate how we can begin to look at them together....

A detailed discussion of the nature of light, how it can travel through a vacuum, and how the speed of light is affected when light travels through a medium.

Japanese theoretical physicist Sin-Itiro Tomonaga resolved key problems with the theory of quantum electrodynamics (QED) developed by Paul Dirac in the late 1920s through the use of a mathematical technique he referred to as...

This interactive activity from the NOVA Web site challenges you to think like Einstein and understand how time travel might be possible.