In their new book, Time Travel and Warp Drives, Tufts physics professor Allen Everett and University of Central Connecticut math professor Thomas Roman explain the science behind the fiction of time travel, and tackle the question: Is it even possible? The authors delve into the lore of sci-fi shows and books to explain how wormholes, warp drives, and parallel universes work; and what Einstein’s theory of relativity is and its relevance to time travel. They also parse through all those pesky paradoxes that arise when one tries to go back in time.