[Yahya A.Sharif (OP)]

Space is finite.
If space is infinite ; mass will cause space-time to move to all directions"space-time won't be curved" and this displacement of space will spread at the speed of light, and there won't be any gravity.

If space is finite, there should be a point where it is fixed to " means this point won't  be curved or  displaced  even if mass exists there " so that mass can curve space-time instead of moving it to all directions , this point which space is fixed to is the end of space.

Gravity speed is the  speed of light, that indicates that space can't be curved if space is infinite, since the curvature idea in fact is not some mass curve  space anywhere including infinity ,  and that because space-time curvature has a finite speed, at this case while gravity approaches 0 and never reach it , then there won't be a fixed point at which space ends,  if so and space is infinite , space will move to all directions"no gravity ", so space is finite

[Kryptid]

I can't make sense out of this.