A blog-lecture version of chapter two section one of Modern Relativity's special relativity Unit at http://www.geocities.com/zcphysicsms/.
The Minkowski diagram was developed in 1908 by Herman Minkowski and provides an illustration of the properties of space and time in the special theory of relativity. It allows a quantitative understanding of the corresponding phenomena like time dilation and length contraction without mathematical equations.
The Minkowski diagram is a space-time diagram with usually only one space dimension. It is a superposition of the coordinate systems for two observers moving relative to each other with constant velocity. Its main purpose is to allow for the space and time coordinates x and t used by one observer to read off immediately the corresponding x' and t' used by the other and vice versa. From this one-to-one correspondence between the coordinates the absence of contradictions in many apparently paradox statements of the theory of relativity becomes obvious. Also the role of the speed of light as a non conquerable limit results graphically from the properties of space and time. The shape of the diagram follows immediately and without any calculation from the postulates of special relativity, and demonstrates the close relationship between space and time discovered with the theory of relativity.