Wikipedia: Einstein\'s Special Theory of Relativity (and, by extension, the General Theory) very explicitly permits a kind of time dilation that would ordinarily be called time travel. The theory holds that, relative to a stationary observer, time appears to pass more slowly for faster-moving bodies: for example, a moving clock will appear to run slow; as a clock approaches the speed of light its hands will appear to nearly stop moving. However, this effect allows \"time travel\" only toward the future: only forward, never backward. It is not the most interesting kind, nor the kind typical of science fiction.