Math of GR
Part 5

In part 2, I claimed that the Minkowski interpretation of Einstein's 1905 theory of Special Relativity (SR) involved a mathematical "space" that was not equal to real space. I admit that it is a great way to see the math and extend it to Riemann Geometry, which is the math used in Einstein's theory of gravity, his General Theory of Relativity (GR), but neither space is the same as our real space where we ski and fly space ships.

In the real space described in SR, you set up two observers, observer 1 and observer 1, with coordinate systems or set of rods XYZ-1 and XYZ-2. Both coordinate systems are set up in the same place. Each axis is touching the other axis. X is up against X1, and so forth. The respective axes coincide and their origins coincide.

Then you set the clock timer at T = 0. Then you let the timer go at the same time that you give the XYZ-2 system some speed, call it V.