People are used to seeing "fake physics" in science fiction - concepts like faster-than-light travel, antigravity and time travel to name a few. The fiction label ought to be a giveaway, but some SF writers - especially those with a background in professional science - are so adept at "technobabble" that it can be difficult to work out what is fake and what is real. To confuse matters further, Isaac Asimov's 1948 piece about the fictitious time-travelling...