Space-Time: a facinating topic to me

I don't remember when I first fallen in love, it's most probably when I was class 3 level. But I can vividly remember that I fallen in love in class 12 with the rich subject Physics.

Einstein's Theory of Relativity(Special and General) facinated me the most.
I'm not going deeper details of that. In fact I don't know the whole thing but I can feel some of them. It's a simple space-time relativeness that is simple but interesting
In Newton's physics, we khow that Space is not absolute(Why?) but Time is absolute.

Now, let a light pulse is sent from one space to another, the distance between the two spaces is relative say it be Srel and time taken by the light to go from one space to another is T.

Then speed of light c = Srel / T.
If T is absolute then the speed of light must be variable.
Einstein says that T also relative, say now it be Trel

Now the equation is c = Srel / Trel

This is just the beginning of Einstein's theory of relativity.