Hard science fiction is a subgenre of science fiction that emphasizes on scientific accuracy and technical plausibility. Sometimes, hard science fiction is referred to as "rigorous science fiction," "scientific science fiction," or "engineering science fiction." Other synonyms for hard science fiction are "hard SF," "speculative science," and "scientifiction." The subgenre typically explores scientific concepts, such as physics, biology, chemistry, and astronomy, and their possible implications on society and individuals. It often features a high level of detail and explanation of scientific and technical concepts, while still creating a cohesive narrative. Hard science fiction contrasts with soft science fiction, which is more concerned with character development and social commentary and less with scientific accuracy.