Is there an end to space? If we choose to side with the mathematicians and scientists who believe that infinity does not accurately describe our universe, then yes. It may well be that infinity is describing something that, while real in abstract mathematics, is not found in our finite universe.

How high is it possible to count? In general, mathematicians and philosophers alike throughout history have agreed that even with potential infinity, it is always possible to add 1 more to a number and get a greater number. There is no limit to how high you can count. We have seen, however, that there are some sets that are even larger than this unending set of counting numbers.

Is there a largest number? Cantor's Great Theorem claims that we can always continue finding larger sizes of infinity by using power sets. (Note: In naive set theory this leads to more paradoxes--can we take the power set of the universal set which already contains every set?)

What does it mean to be infinite? It depends who you ask. We have potential infinity and actual infinity to deal with, not to mention all those critics who think infinity is just man's invention and doesn't really exist.

How big is infinity? Cantor showed us that there are many different sizes of infinity--there's actually an infinite number of sizes of infinity.