In discussing the scientific content of sf it is customary to regard the sciences as ranging from "hard" to "soft", with physics lying at the hard end of the spectrum (> Hard SF). A concern with the hard sciences is generally held to have characterized sf of the period 1940-1960, or a type of sf whose locus classicus is to be found in that period, and so we may expect this type of sf, in its scientific aspect, to be dominated by physics. In fact a large part of the importance in sf of physics can be attributed to its association with Technology; among the pure sciences, Astronomy and Biology have probably provided more motive force for hard sf than has physics. Nevertheless, physics is prominent in the ideological and cultural background to sf, and its influence can often be detected even when it makes no explicit contribution to a story. A familiarity with physical ideas and an ability to deploy the language of physics have been used by many authors to establish a general scientific atmosphere, a good example being Isaac Asimov's Three Laws of Robotics, which borrow the form of Newton's Three Laws of Motion so as to claim the same seminal impact.
The two areas of physics which have been most popular with sf writers, Gravity (see also Antigravity) and Relativity (see also Faster Than Light), are covered in the relevant entries. Ideas from physics have been applied to technology constantly since Hugo Gernsback or even Jules Verne, but in such writing the interest usually lies in the application. Some writers seem to feel that the motivation of fundamental research lies entirely in its applications. Tom Godwin, for example, in "Mother of Invention" (December 1953 Astounding), changes the proverb and proposes that necessity is the mother of Invention; he shows the crew of a crashed spaceship developing a new theory of gravitation which enables them to design an Antigravity generator to lift their ship. The most extreme example of this attitude is embodied in Raymond F Jones's "Noise Level" (December 1952 Astounding), which argues that, if we only try hard enough, we can discover any laws of nature we should like to be true.
Many imaginary inventions and strange events are based on points of physics, though sometimes the explanation of the modus operandi amounts to no more than a translation into technical terms of the everyday description of its effect – as in H G Wells's explanation in The Invisible Man (1897) that the Invisibility potion works by giving human flesh a refractive index of one. An effect at the opposite pole to this was envisaged by Bob Shaw in his invention of Slow Glass in "Light of Other Days" (August 1966 Analog), in which light travels so slowly that it takes several years to travel through the thickness of a window pane. (Realizing that it would not give quite the effect he wanted, Shaw was obliged to reject the description of slow glass as simply having a very high refractive index.)
Part, if only a small part, of the effectiveness of the idea of slow glass lies in the way it provides an imaginative realization of a physical fact that in normal experience remains merely theoretical knowledge, namely the finiteness of the speed of light. This kind of imaginative exploration of physics can be seen in its purest form in James Blish's "Nor Iron Bars" (November 1957 Infinity Science Fiction), which is an attempt to provide a picture of the inside of an atom and the quantum behaviour exhibited by electrons, utilizing the device of having a spaceship shrink to subatomic size and move inside an atom as if it were a solar system. This was one of the very few sf stories before the mid-1970s to make any substantial use of quantum phenomena. Blish adopted a similar approach to a more familiar area of physics in his famous microscopic-world story "Surface Tension" (August 1952 Galaxy).
Ideas from physics have been used in postulating new forms of life. The favourite basis for these is electromagnetic fields, either in isolation, as in Fredric Brown's "The Waveries" (January 1945 Astounding) and Bob Shaw's The Palace of Eternity (1969), or in conjunction with inorganic matter, as in Fred Hoyle's The Black Cloud (1957), the latter having something in common with the sentient suns in Olaf Stapledon's Star Maker (1937). Blish's "The Weakness of RVOG" is about a creature whose energy source is one of the fusion cycles which Bethe proposed as taking place in stars (this creature communicates by modulating light waves rather than sound waves). In Fredric Brown's "Placet is a Crazy Place" (May 1946 Astounding) there are birds, made of condensed matter, which fly through the rock of a planet as if it were air. StanisLaw Lem's Solaris (1961; trans 1970) postulates life formed from a new type of matter composed entirely of neutrinos. Shaw's A Wreath of Stars (1976) postulates an antineutrino world whose form of matter can interpenetrate with that of our own. Neutrinos are particles which have no properties other than momentum and spin, and interact only very weakly with other particles, so that they are very difficult to stop. Their seeming utter harmlessness is the point of Ralph S Cooper's Satire "The Neutrino Bomb" (July 1961 LASL News); their delicacy underlies the idea of "neutrino acupuncture" in "Six Matches" (in Shest' spichek, coll 1960 as title story) by Arkady and Boris Strugatski. Later, somewhat undermining the joke of "The Neutrino Bomb", it was realized that the gigantic neutrino flux from a supernova explosion could indeed be lethal – as expounded in clinical detail in Charles Stross's Iron Sunrise (2004).
The last four examples make use of the branch of physics which, together with Cosmology (including theories of Black Holes), has undergone dramatic development in the last decade and therefore has the most obvious potential for sf; the physics of elementary particles. Subnuclear physics provides one of the ideas in Isaac Asimov's The Gods Themselves (1972), which postulates a parallel universe whose strong nuclear force is greater than in ours; pumping electrons between the two universes provides a source of energy in both. Some of the more striking ideas in the field of particle physics concern condensed matter, Antimatter and neutrinos. Condensed matter is of two kinds: "electron-degenerate" matter, the material of white dwarf stars, in which the atoms are compressed as close as they can be while remaining atoms (a matchboxful would weigh several tons); and nuclear matter ("neutronium"), the material of Neutron Stars, which has the density of the atomic nucleus (a pinhead of it would weigh several thousand tons). Degenerate matter features in "Placet is a Crazy Place" and in Paul Capon's juvenile novel The Wonderbolt (1955); and nuclear matter in Larry Niven's "There is a Tide" (July 1968 Galaxy).
Antimatter (which see) is composed of particles which are the opposite in all respects to those which compose ordinary matter; when matter and antimatter meet, they mutually annihilate in a burst of radiation. A E van Vogt's "The Storm" (October 1943 Astounding) is about a storm in space that takes place when an ordinary gas cloud meets a cloud of antimatter gas. Some more of the craziness of Placet in Brown's story comes from its orbiting two suns, one of matter and the other of antimatter. Larry Niven describes an antimatter planet in "Flatlander" (March 1967 If). The correspondence between an electron and its antiparticle, the positron, was used by Blish in "Beep" (February 1954 Galaxy) as the basis of a method of instantaneous signalling, following ideas suggested by the original description by Paul Dirac (1902-1984) of the positron (> Dirac Communicator). The formation of matter and antimatter universes in the first fraction of a second of creation, and some extremely hypothetical consequences for the nature of our reality, are treated in The Jonah Kit (1975) by Ian Watson, who blends real and imaginary physics very adroitly throughout the book.
Stories which turn on fairly elementary points of physics include: Arthur C Clarke's "A Slight Case of Sunstroke" (September 1958 Galaxy as "The Stroke of the Sun"; vt in Tales of Ten Worlds, coll 1962), in which the spectators at a football match hold their glossy programmes so as to form an enormous parabolic mirror focusing sunlight on the referee, an improvised and lethal solar furnace; Clarke's "Silence, Please!" (Winter 1950/1951 Science Fantasy), in which the phenomenon of wave-interference is jokily used as the basis for a silence generator; Robert A Heinlein's "Let There Be Light" (May 1940 Super Science Stories) as by Lyle Monroe, which suggests that the relationship between radio waves and light waves could be used to provide a cold light source; and Larry Niven's "A Kind of Murder" (April 1974 Analog), in which the fact that potential energy and heat are interchangeable forms of energy is exploited in an attempt at a perfect murder. The Dispossessed (1974) by Ursula K Le Guin is unusual in sf in that much of the story is focused on an attempt to recreate the thought processes and psychology of a physicist whose theories regarding simultaneity and the nature of time would create a revolution in physics comparable to that initiated by Einstein's Relativity theories. Le Guin's physics is imaginary though plausible and presented with conviction (> Imaginary Science); her psychology might very well be accurate.
Finally, since measurement is of fundamental importance in physics, this is the place to mention those stories that make the point that all physical measurements are relative. It was put in its simplest form by Katherine MacLean in "Pictures Don't Lie" (August 1951 Galaxy); it was put further into the context of physics by Philip Latham in "The Xi Effect" (January 1950 Astounding), observing that there would be no observable consequences if everything in the Universe were to contract at the same rate (although the contraction would become observable and ultimately disastrous if the wavelength of visible light stayed constant). Referring to time rather than length, Blish described in "Common Time" (August 1953 Science Fiction Quarterly) an oscillating discrepancy between a man's internal (mental) time and external (physical) time.
Since the appearance of Black Holes in sf in the mid-1970s there has been something of an upsurge of physics themes; most relate to Cosmology, but a number of stories concern quantum physics, not necessarily cosmological. Often these stories take metaphors from physics rather than physics itself; one of the first such ideas drawn from physics and thereafter used as a metaphor is Entropy (which is from thermodynamics, not quantum physics), and many such stories are discussed under that head. An even older example is Heisenberg's Uncertainty Principle, formulated in 1927, which regularly appears both within and outside sf, usually not in its strict meaning but as a kind of "proof" from the world of physics that we can no longer be sure of anything, and that all the old certainties are gone. The Schrödinger's Cat Thought Experiment has popped up so often as almost to have become a Clichés, as in "Schrödinger's Cat" (in Universe 5, anth 1974, ed Terry Carr) by Ursula Le Guin, the Schrödinger's Cat trilogy (1979-1981) by Robert Anton Wilson, The Coming of the Quantum Cats (1986) by Frederik Pohl and "Schrödinger's Kitten" (September 1988 Omni) by George Alec Effinger. The attraction of this idea is that, according to the many-worlds interpretation of quantum physics formulated in the late 1960s by Hugh Everett, John Wheeler and Neill Graham – who took the fate of Schrödinger's possibly murdered cat (a half-dead, half-live wave function until somebody comes to look at it, at which point it collapses into one state or the other) as their starting point – the cat's fate gives an imaginative warrant for the existence of Parallel Worlds. Perhaps the wittiest use of ideas from quantum physics appears in Connie Willis's "At the Rialto" (October 1989 Omni), which describes the extraordinary quantum uncertainties that vex a congress of quantum physicists at a large hotel. It behoves us all to remember the remark of physicist Niels Bohr (1885-1962): "Those who are not shocked when they first come across quantum theory cannot possibly have understood it."
Concepts of cutting-edge physics, such as supersymmetry, string theory and (mem) rane theory, have perhaps become too abstruse for serious and knowing deployment in sf. Several writers have bravely dropped the appropriate names – as past authors might refer glibly to magnetism or radium – into more or less plausible contexts. Thus Stephen Baxter casually posits a Susy (supersymmetry) drive capable of moving his Spaceship at Faster-than-Light speeds in "The Quagma Datum" (in Interzone: The 4th Anthology, anth 1989, ed John Clute, David Pringle & Simon Ounsley), and features a GUTship (whose drive is based on some Grand Unified theory of physics) in Ring (1994). Exotic Weapons in Alastair Reynolds's Revelation Space (2000) include a "supersymmetry beam" and a "quark deconfinement device". Justina Robson makes cautiously distanced play with brane theory in Natural History (2003).
Among those who have used ideas from physics with considerable sophistication and know-how are a number of writers of Space Opera and adventure on other planets, including old stagers like Larry Niven and Arthur C Clarke but also newer authors, in their turn expanding the genre, like Stephen Baxter, Greg Bear, Gregory Benford, David Brin, Robert L Forward, Paul J McAuley, Charles Sheffield and John E Stith. More detailed accounts of their work, and other relevant users of themes from physics, will be found by following up the various cross-references above as well as Big Dumb Objects, Dyson Sphere, Force Field, Ion Drive, Macrostructures, Mathematics, Space Warp and Tachyons. [TSu/PN/DRL]
see also: Elements; Independence War: The Starship Simulator; Microsoft Space Simulator; Omega Point.
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