NOVA: Einstein's Big Idea - Learn about Einstein's general relativity and how the theory might help to describe the nature of the universe. Article describes how his work helped other scientists to discover the big bang theory and black holes. - http://www.pbs.org/wgbh/nova/einstein/relativity/
How Special Relativity Works - Helps understand the basic elements related to the topic. - http://science.howstuffworks.com/relativity.htm