When reading about space and time on this board it got me thinking. What is space-time? Does it have any properties of it’s self or is it simply something where things can happen?
So I thought of a box. Imagine this box (1 cubic mile) that is impenetrable to all particles, fields and forces including gravity. Next you need some kind of theoretical machine that can suck out any remaining particles, fields and forces including gravity from inside the box.
So what are you left with? What properties does this box contain? Is their some way that you can define what is in the box?
The only property that is left that springs to mind is distance. You can still say that you have got half way across the void by comparing yourself to the box. But then is that a property of the box or the void?
As nothing will ever change in the box can you say that time is passing? If you can how could you measure the passing of time?
I guess this would go in Big Bang and Cosmology
™ Version 4.2