On Entertainment, Extrapolation, and the Suspension of Disbelief Science Fiction can teach, but that isn't it's purpose.  Anyone who is interested in real science is much better served by acquiring a textbook.  No, we as fans pay for science fiction (and support the writers) because it entertains us, while at the same time challenging us with new ideas.  The blurry line that divides "good" science fiction from cheap sci-fi is the extent to which the author was able to extrapolate from known science and present a story in which no known scientific principals are violated, versus making things up out of whole cloth.  An example of the former would be the matter-antimatter reactors in Star Trek.  An example of the latter would be the liquid fuel "Naquata" from Stargate SG-1.  In the hands of the writers, naquata has become a magical substance with all sorts of unusual properties, because there's no real science to keep the writers honest.  Anti-matter on the other hand, is something that scientists know quite a lot about.  a knowledgeable person watching the Star Trek crew deal with the difficulty of shutting off an anti-matter flow without disrupting the magnetic bottle that contains it, will appreciate that the author is presenting a realistic portrayal of the difficulties and consequences of using anti-matter as a power source. To truly enjoy most types of fiction, one must be able to engage a willing suspension of disbelief that the events can (or did) happen.  Within science fiction, "magical" substances and devices strain a person's ability to maintain that state of disbelief.  Out and out violations of known science are even worse: the illusion is utterly destroyed beyond repair, and the fan is left angry and frustrated.  A perfect example of this class of mistake is a banked turn in space.  It looks good on the screen, but what exactly are they banking against?  Battlestar Galactica was the worst offender here, but Star Trek does it too, and I hate it every time I see it.  For an example of space combat done right, watch Babylon 5. Below are links to pages where I discuss selected movies, TV shows, and books in greater detail: