Question: how can something like space be infinte? and if it space isn't then where does it end?

Martin Archer answered on 13 Mar 2013:

Infinities are hard to grasp, in fact it makes the best of people’s heads hurt thinking about them including mine sometimes. We don’t really know if space is infinite or not, personally I don’t think it is. But just because space isn’t infinite it doesn’t have to have an end. Think of the surface of the Earth, that isn’t infinite but because it’s wrapped around there is no start and end. So I think the Universe could be like this, keep going in one direction far enough and you might end up back where you started. Some scientists have done experiments to work out if this is the case and they haven’t found any evidence of “curvature” yet, but that doesn’t mean it’s not there. We can’t tell the Earth is a sphere by eye, it’s only over much larger distances that we can work it out… the same may be true of the Universe. But ultimately at the moment we don’t know.