One of the biggest dangers in writing speculative fiction, especially science fiction, is speculating poorly. For example, according to Space 1999, there should have been a fully functioning moonbase in operation eight years ago. Of course, with a well told yarn most readers are very forgiving towards writers. That’s a good thing, because writing speculatively is fraught with opportunities to make goon of yourself. These days, writing poorly is rarely forgiven. The avid reader of sci-fi is well aware of how far a light year really is and understands the basic physics of flight, gravity and so on.
But there is an upside in that many stories told in years past were riddled with awful interpretations of what might come to pass and bursting with atrocious liberties taken with physics, but they were classics of their time. We can still enjoy these good tales while chucking quietly at the ridiculous premises on which the tale was built.
I recently came across this article on the net that has some great examples. It’s well worth a read. Sci Fi Writers Have No Sense of Scale – enjoy.