Why do they asume that the big bang is the origin of the universe? While the big bang might have occurred, it is not the "origin" of the universe. It at most is the origin of the expansion of matter through the universe. Think about the universe as a huge infinite vacuum that contains matter within it. The vacuum is infinite. Why? For the simple reason that it is not matter. It is nothing actually. It is the absence of matter, of existence, of time. That kind of thing does not need to have "edges" or "origins". What is finite and what has edges is matter but again, i think scientists are confused as to what is the universe, and what is the matter within it. The universe is not a box or something that is composed of anything other than pure nothing. Or maybe im getting something wrong, what do you think?