Hard science fiction is a type of science fiction that focuses on scientific accuracy and logical reasoning. The term was first written about in 1957 by P. Schuyler Miller in a review of John W. Campbell's Islands of Space in the November issue of Astounding Science Fiction. The opposite term, "soft science fiction," was created by comparing it to the common difference between "hard" (natural) and "soft" (social) sciences. This term appeared in the late 1970s. Examples of hard science fiction include Isaac Asimov's Foundation series, which uses mathematical sociology. Science fiction critic Gary Westfahl explains that while the terms "hard" and "soft" are not part of a strict classification system, they are helpful ways to describe stories that reviewers and commentators find useful.

History

Stories about science and technology were written as early as the 1870s. One example is Jules Verne's Twenty Thousand Leagues Under the Seas, published in 1870. The careful details in Verne's work inspired many future scientists and explorers, even though Verne claimed he was not writing as a scientist or predicting future machines and technology.

Hugo Gernsback believed science fiction stories should teach readers about science when he started working with the genre in the 1920s. However, he soon had to include stories with less scientific accuracy in Amazing Stories to attract readers. During Gernsback's long break from publishing science fiction, from 1936 to 1953, the genre moved away from focusing on facts and education. The Golden Age of Science Fiction is usually said to have begun in the late 1930s and ended in the mid-1940s. Historians Peter Nicholls and Mike Ashley called this time "a quantum jump in quality, perhaps the greatest in the history of the genre."

Gernsback still believed science fiction should focus on science. In his first editorial for Science-Fiction Plus, he criticized stories that were "fairy tales" or "weird" and claimed they were not real science fiction. He preferred stories that were "truly scientific" and predicted future science. In the same editorial, Gernsback suggested changes to patent laws so science fiction writers could apply for patents for their ideas, even if no models existed. He argued this was needed because many ideas in a book called Ralph 124C 41+ described technologies that came before they could be built.

Definition

The term "hard science fiction" refers to how science is used in a story and how closely it follows real scientific knowledge. A key rule for hard science fiction is that stories should aim to be accurate, logical, and based on current scientific and technical understanding. This includes explaining technologies, events, and situations that are either possible now or could be possible in the future. For example, ideas about spaceships, space stations, and space missions from the 1950s and 1960s inspired many stories about space in hard science fiction.

Academic Jessica Imbach explains that hard science fiction follows the known physical laws of the universe and avoids using magic. However, this does not always mean that the futuristic events in these stories are more realistic than those in other types of science fiction or fantasy.

Even if new discoveries later prove some ideas in hard science fiction incorrect, the label "hard SF" can still be valid. For example, P. Schuyler Miller called Arthur C. Clarke’s 1961 novel A Fall of Moondust hard science fiction. A key part of the story, the existence of deep "moondust" pockets on the Moon, is now known to be false. However, the story was still considered hard science fiction at the time it was written.

There is some flexibility in how much a story can differ from real science and still be called hard science fiction. Authors of hard science fiction only use ideas that are based on well-known scientific or mathematical principles. In contrast, authors of softer science fiction may use ideas that are not supported by science (sometimes called "enabling devices" because they help the story work).

Readers of hard science fiction often look for mistakes in stories. For example, a group at MIT found that the planet Mesklin in Hal Clement’s 1953 novel Mission of Gravity would have a sharp edge at its equator. A high school class in Florida calculated that in Larry Niven’s 1970 novel Ringworld, the topsoil would have slid into the seas within a few thousand years. Niven corrected these errors in his later book The Ringworld Engineers and mentioned them in the book’s introduction.

Representative works

Arranged in order of when they were published.

• David G. Hartwell and Kathryn Cramer (eds.), The Ascent of Wonder: The Evolution of Hard SF (1994)
• David G. Hartwell and Kathryn Cramer (eds.), The Hard SF Renaissance: An Anthology (2002)
• Ben Bova and Eric Choi (eds.), Carbide-Tipped Pens: Seventeen Tales of Hard Science Fiction (2014)
• Michael Brotherton (ed.), Science Fiction by Scientists (Springer, 2017)
• Wade Roush (ed.), Twelve Tomorrows (MIT Press, 2018)

• Robert Heinlein, The Past Through Tomorrow collection of stories (1939–1962)
• Tom Godwin, "The Cold Equations" (1954)
• Poul Anderson, "Kyrie" (1968)
• Frederik Pohl, "Day Million" (1971)
• Larry Niven, "Inconstant Moon" (1971) and "The Hole Man" (1974)
• Greg Bear, "Tangents" (1986)
• Geoffrey A. Landis, "A Walk in the Sun" (1991)
• Vernor Vinge, "Fast Times at Fairmont High" (2001)

• Aldous Huxley, Brave New World (1932)
• Hal Clement, Mission of Gravity (1953)
• Fred Hoyle, The Black Cloud (1957)
• James Blish, A Case of Conscience (1958)
• Jack Vance, The Languages of Pao (1958)
• Arthur C. Clarke, A Fall of Moondust (1961)
• Stanisław Lem, The Invincible (1963)
• John Brunner, Stand on Zanzibar (1968), The Jagged Orbit (1969), The Sheep Look Up (1972), The Shockwave Rider (1975)
• Philip K. Dick, Do Androids Dream of Electric Sheep? (1968)
• Michael Crichton, The Andromeda Strain (1969), Jurassic Park (1990)
• Larry Niven, Ringworld (1970)
• Poul Anderson, Tau Zero (1970)
• James Gunn, The Listeners (1972)
• Larry Niven and Jerry Pournelle, The Mote in God's Eye (1974)
• Bob Shaw, Orbitsville (1975)
• James P. Hogan, The Two Faces of Tomorrow (1979)
• Robert L. Forward, Dragon's Egg (1980) and its sequel Starquake (1985)
• Steven Barnes and Larry Niven, The Descent of Anansi (1982)
• Carl Sagan, Contact (1985)
• Kim Stanley Robinson, The Mars trilogy (Red Mars (1992), Green Mars (1993), Blue Mars (1996)), The Ministry for the Future (2020)
• Nancy Kress, Beggars in Spain (1993)
• Charles R. Pellegrino & George Zebrowski, The Killing Star (1995)
• Allen Steele, The Tranquillity Alternative (1996)
• Greg Egan, Schild's Ladder (2002)
• Alastair Reynolds, Pushing Ice (2005)
• Cixin Liu, Remembrance of Earth's Past (trilogy, 2006–2016)
• Andy Weir, The Martian (2011), Project Hail Mary (2021)

• Destination Moon (1950)
• 2001: A Space Odyssey (1968)
• Colossus: The Forbin Project (1970)
• The Andromeda Strain (1971)
• Silent Running (1972)
• Blade Runner (1982)
• The Abyss (1989)
• Contact (1997)
• Gattaca (1997)
• Primer (2004)
• Moon (2009)
• Europa Report (2013)
• Her (2013)
• Gravity (2013)
• Ex Machina (2014)
• Interstellar (2014)
• The Martian (2015)
• Arrival (2016)
• Ad Astra (2019)
• Project Hail Mary (2026)

• The Expanse (2015–2022)
• For All Mankind (2019–present)
• Away (2020)
• Pantheon (2022–2023)
• 3 Body Problem (2024–present)

• Destination Moon (1953)
• Explorers on the Moon (1954)
• Patlabor (1988–present)
• Ghost in the Shell (1989–present)
• Planetes (1999, 2004)
• Rocket Girls (2007)
• Revisions (