I am currently studying special relativity on my own and I am looking into space time and space time diagrams. While reading through various sources I came across what seemed to be two methods to describe space time. X0, X1, X2, X3 (ct, x,y,z) -> Lorentz Metric X1, X2, X3, X4 (x,y,z,ict) -> Minkowski Metric The two "metrics" are confusing me. I understand that both systems were formed so that all 4 dimensions have the same units. However, I don't know which one to use and I dont really understand how each metric system was formed (the thought process behind their creation). The Minkowski metric is especially confusing for me due to the imaginary "ict" factor. I think the differences in the metric system also has to do with the signs of each term. For example i see both these notations floating around (-+++) and (+---). Any help would be greatly appreciated.