A lot of very readable and entertaining SF is grounded in Clarke's observation that "any sufficiently advanced technology is indistinguishable from magic." A character who pops what looks like an aspirin tablet into what looks like a microwave and then retrieves and eats a vindaloo is behaving as realistically as I am when I order a pizza. If the character then steps into a time machine, he or she needn't know any more about how it works than I need to know what really happens when I turn on the lights. In fact, I'd worry about the success of a book that said "Gwen's knowledge of farming and baking enabled her to eat a pizza, and since she understood the principles of electrical transmission, she was able to eat it with the lights on." If anything, I think that too many SF books try to explain made up science that their characters, if real, would probably just take for granted.
If you're into stuff like this, you can read the full review.