This article is from the Relativity and FTL Travel FAQ, by Jason W. Hinson jason@physicsguy.com with numerous contributions by others.
The main goal of this introduction is to make relativity and its
consequences feasible to those who have not seen them before. It should also
reinforce such ideas for those who are already somewhat familiar with them.
This introduction will not really follow the traditional way in which
relativity came about, but it will try to explain the concepts through an
easy to follow perspective. After discussing the basic terminology, the
introduction will discuss points in the pre-Einstein view of relativity. It
will then give some reasoning for why Einstein's view is plausible. This
will lead to a discussion of some of the consequences this theory has, odd
as they may seem. Finally, I want to mention some experimental evidence that
supports the theory.
 
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