How much space is there between the past and the future? Dumb question?
Maybe.
That space is where we exist in the present, the ever-fleeting now.
Think it through.

The past does not exist. It's gone, never to be repeated, and not available to revisit, unless one can travel faster than the speed of light, in which case, one would only see the past as fluttering images much like in the cinema.

The future has yet to happen, so it also does not exist. One could travel at the speed of light and...