Question: where does space end?

Tim Duckenfield answered on 8 Mar 2018:

Well it depends how you look at it. The furthest we can ever see is how far light could have traveled in the lifetime of the universe. By that I mean the universe is about 13.8 billion years old, and light travels a distance of one “light-year” in a year, so the furthest we can see is 13.8 billion light years.

We think space is expanding though, and is curved, which makes a really detailed answer quite complicated! Sadly for us humans, we just don’t live long enough and can’t travel fast enough to see much of space, it is just so big!