Originally Posted By: Bill S.
Scoratus; could you please explain what the minus 4D continuum is?

One of Einstein’s postulate says that particle – quantum of light-
moves in a straight line with speed c=1 in the vacuum.
So, in SRT we have one reference frame and it is vacuum.
But because Einstein took Time as a length (1 sec= 299,792,458 m)
Minkowski decided to take this time as a fourth coordinate
and created his minus 4D continuum. And we lost the direction.
But the root of theory is the postulate:
constant and independence speed of quantum of light in the vacuum.
==.
So, in my opinion the essence of Einstein’s SRT is question:
What will be happen if the particle – quantum of light – changes
its constant and straight movement in the vacuum.
=========.
Israel Socratus.
==============..