Scientific American interviews Michio Kaku (A theoretical physicist) and discusses the notion of time travel. I've always found this topic extremely interesting but it also always seems to tie my brain into knots. Like how smart do you have to be to comprehend the potential existence of "quantum foam" or have a logical (but unproven) answer to the "Grandfather Paradox"?

The scientist seems to think that time travel is possible, just not by us - perhaps by a vastly superior group of beings.