Genres
Hard science fiction
Science fiction built on concern for scientific accuracy and logic, staying rigorous in its use of known science.
Hard science fiction is a category of science fiction characterized by concern for scientific accuracy and logic: stories aim to be accurate, logical, credible and rigorous in their use of current scientific and technical knowledge, and generally adhere to known physical laws. Arthur C. Clarke, Larry Niven's Ringworld and Andy Weir's The Martian sit on the shelf's shortlist.
For novel and web-serial writers the genre is a promise with a maintenance cost: readers expect the science to hold, so every extrapolation stated on the page becomes canon the serial must keep straight. The line against soft science fiction is emphasis, not quality; the full contrast is laid out in the guide to hard vs soft science fiction.