As prolific science writer and physicist Barrow regularly remarks, infinity is not merely the smallest or biggest thing, or the longest time imaginable: it's a quality that is unimaginable. It's thus a paradox that mathematicians, physicists, and philosophers have discovered quite a bit about infinity, albeit with different degrees of certitude. As also related in David Foster Wallace's Everything and More: A Compact History of Infinity (2003), Barrow recounts the career of German mathematician Georg Cantor, whose explorations of set theory resulted in fundamental proofs about infinities (some are bigger than others, for example). However joyous such discoveries are to the numbers masters, physicists' encounters with infinities are less rapturous because they hint at deficiencies in general relativity; hence their joy over string theory, which eliminates infinities that arise in calculations about the big bang and black holes
