What is it expanding into? Will it ever stop? Will we ever be able to go outside the zone it is expanding into?

Most people find it extremely difficult to understand the nature of the universe. First of all, it is widely accepted that the universe is shaped like a ball. However, there is only the space between stars and galaxies; there is no interior or exterior. The universe expands, creating space, but it is not expanding "into" anything. One way to visualize the universe is to picture a partially full balloon; the universe is the surface of the balloon, and only the surface.

Space and time are both created by the expansion of the universe. The equations of relativity indicated that before the expansion of the universe started neither space nor time existed. As the universe expands more space is created. What existed in what becomes space due to the expansion of the universe as far as is known is nothing.

The supernova experiments of 1997 and 1998 proved that the rate of the expansion of the universe is increasing. This means that the expansion of the universe will continue until there is effectively nothing left but "empty " space.

Matter can only exist within space time. To go outside the space time continuum would require become immaterial

The universe is expanding into itself; it is not expanding into any particular external space. Given the constraints imposed by the speed of light and the ongoing expansion, it is unlikely that we will be able to travel outside the observable universe.