y'know, whenever someone brings this up, I always feel obligated to quote the great man Trey Parker.
"Basically ... out of all the ridiculous religion stories—which are greatly, wonderfully ridiculous—the silliest one I've ever heard is, "Yeah ... there's this big giant universe and it's expanding, it's all gonna collapse on itself and we're all just here just 'cause ... just cause." That, to me, is the most ridiculous explanation ever."