(Click on that for the full picture. DO IT. DO IT NOW.)
This question plopped into my inbox like a month ago now.
Name: Justin M.
Question: How can physicists determine the shape of the universe, and what implications might the different speculated shapes of the universe have?
And I’ve been avoiding it ever since, because if you mean what I think you mean it’s an insanely hard subject to try to explain to somebody who hasn’t done, say, three years of an undergraduate physics degree course.