Fantasy: impossible persons, places, things, or happenings,
without pseudoscientific explanations. Science fiction: The same,
with pseudoscientific explanations.
Hard science fiction: science fiction in which
some bit is worked out according to real science, e.g., an orbit is calculated. "Horror", "adventure", "humor" etc. are plotted on a different axis. —
user14111 May 7 '16 at 1:33