(Image credit: Ballantine Books / Amazon MGM) Science fiction is not monolithic. There are, in fact, two major sub-genres that divide sci-fi — hard sci-fi and speculative (or soft) sci-fi — and most of the time, the delineation between the two is pretty clear. Hard sci-fi is all about scientific accuracy and logic; it might contain technology and science we don't yet have, but it's all stuff that can exist in our current understanding. Speculative sci-fi, meanwhile, plays a little hard and fast with the known rules of the universe to tell exciting and fantastical stories. These are two staunch pillars that hardly ever meet. Article continues below How it does this is really impressive, but what’s really striking is that the film does not walk this line at all, falling much closer to speculative sci-fi. How does the novel balance on a sub-genre knife-edge, and why doesn’t the film do this? Let’s take a look. Space Wizards vs.…