介绍了关于真空中光速的假定的重要作用,它不仅是相对论理论的基础,而且使人们能够定义同时性并测量空间距离.
In this paper,we introduce the important role of the postulate about light velocity in the empty space,which is not only the foundation of the theory of relativity,but also enables us define the simultaneity of time and distance of space.