Hard Science Fiction is a genre of speculative storytelling that emphasizes scientific accuracy and technical detail. Writers in this tradition build futures that are constrained by known physics, engineering, and mathematics, creating plausibility through rigor.
This contrasts with more fantastical science fiction, where imagination may bend or break established laws. In hard SF, the narrative often arises from the consequences of real science extended into the future.
The genre is closely related to Forecasting, since it projects current knowledge into probable futures. It also overlaps with World Building, as careful attention to scientific detail helps construct immersive and believable environments.
Hard Science Fiction has inspired innovation in aerospace, computing, and biotechnology, influencing projects like SpaceX and other real-world attempts to turn speculative visions into practice.