Time warp. Computer illustration depicting a warped pocket watch against a multi-coloured background. This could be used to illustrate one of the concepts of Einstein's Theory of Special Relativity - that time is not absolute but depends on the relative motion of the observer and that which is being observed. Einstein later showed that time and space are different dimensions of the same thing - spacetime - which could be warped by gravitational fields. Science fiction writers often use the concept of warped spacetime to allow travel at speeds above that of light - something expressly prohibited by Einstein's theories.