Is space really infinite ???

Beyond the finite universe is: nothing. No time, no space, no vacuum...there is literally nothing. But there's not an "edge" to the universe, where you'd just be flying in your spaceship and come upon a huge impenetrable wall beyond which is nothing. Think of a person traveling on the surface of the Earth. The Earth is finite, yet you could walk forever in a straight line and never reach the end. In fact, depending on which direction you go, you could eventually come right back to where you started.

Same with the universe, only in one more dimension (at least). You could fly your spaceship forever in any given direction, and instead of hitting the end, you're just traveling around in this finite, but "circular" space-time structure.