Special Theory of Relativity without Imaginary X4 = ict Coordinate

Abstract

With introduction of imaginary time coordinate X₄=ict the question has raised whether this coordinate has a real physical existence or it is only a mathematical tool. In this paper it is shown that Special Theory of Relativity can be described without the imaginary coordinate X₄ within a three dimensional Euclid space, where time t which we measure with clocks is a numerical sequence of motion, i.e., a material change within a three dimensional physical space.