Expanding universe

[Henryn]

If the universe is continually expanding, what is expanding into?

[Isaacr]

Most scientists agree that the universe has been expanding since the Big Bang, an initial 'explosion' of matter, time and space from a single point. This explosion created everything in the Universe - including the space between matter, and time itself. Expansion is the natural result of any explosion as particles are thrown away from each other. In a sense, this is what's happening to the Universe except that it's not really the matter that's expanding, it's the space. So, the question is actually meaningless as the Universe isn't expanding into anything because it doesn't have any edges over which it spills. The term Universe is used to describe EVERYTHING, therefore they can be nothing 'outside' for it to expand into.