This list was in part inspired by my previous post, Tired Sci-Fi Tropes That Must Be Retired.
Law of Selective Gravitation: All artificial bodies in space generate an internal gravitational field, equal to one gee, with “down” defined as the “bottom” of the body; this gravitational field somehow terminates exactly at the outer hull of the body, even if it is irregularly shaped.
First Law of Gravitational Irrelevance: a spacecraft may travel from a planet’s surface into space in the same manner in which an airplane gains altitude, ignoring the need to achieve escape velocity.
Second Law of Gravitational Irrelevance: a spacecraft may fly directly towards or away from a planet or other large celestial body, ignoring the fact that objects in space must describe elliptical orbits about each other.
Law of Inertial Dampening: No matter how much kinetic energy is directed at an inhabited body (in space or on a planet), the resulting disruption will be enough to jostle the inhabitants and cause minor structural damage – nothing more or less.
Law of User Interface Equivalence: When a spacecraft or space station takes damage to any structural component, the computer screen or workstation used to monitor that structure from the bridge or engineering center will explode.
Law of Ethical Xenopolymorphism: While malevolent aliens come in many forms, beneficent aliens are always humanoid.
Law of Sexual Xenopolymorphism: Humanoid alien females will always have mammalian secondary sexual characteristics (breasts, wide hips, full sensual lips), even if they are non-mammalian (lizard, avian, piscine, insectoid, etc.).
Newton’s Fourth Law of Motion: In space, constant thrust equals constant velocity.
Kubrick’s Law of Motion in Microgravity: all motion in a “zero gravity” or microgravity environment will take place at 22% of the speed it would occur at sea level; this applies to animate persons as well as inanimate objects.
Exception to Kubrick’s Law of Motion in Microgravity: persons in a “zero gravity” or microgravity environment may speak at normal speed.
Allen’s Law of Motion in Microgravity: objects freely floating in a “zero gravity” or microgravity environment will behave as if suspended from a transparent thread within a full gravity environment.
Law of Sound in a Vacuum: Despite the lack of a medium for transmission, sound will travel in a vacuum, with precisely the same properties as in the Earth’s atmosphere at sea level.
First Law of Combustibility: Anything important – spaceships, planets, robots – explodes when it is critically damaged, whether any combustible material is present or not.
Second Law of Combustibility: When anything explodes, the mass of the resulting ejecta will be less than 2% of the object’s original mass; the remainder of the mass ceases to exist.
Third Law of Combustibility: When objects explode in space, all matter that makes up the object comes to a complete stop relative to the observer, whatever its previous velocity. The explosion will then expand in an equal sphere away from the point where the object stopped.
Fourth Law of Combustibility: All objects that explode in space produce a discrete ring that expands ahead of the main shock wave; this is a fundamental principle of Aesthetic Physics.
Fifth Law of Combustibility: The shock wave of an explosion is confined to the visible fiery ball of the explosion; and both will move at 98% of the speed of anyone attempting to fly, drive or run from the explosion. After a certain distance, the speed of the shock wave will quickly drop off for no apparent reason.
Sixth Law of Combustibility: The destructive force of a nuclear warhead, and the resulting deadly radiation, cannot penetrate the skin of a typical 1950s consumer-grade kitchen refrigerator.
First Law of Practical Stellar Physics: as an observer approaches a star, the brightness of the visible light it gives off diminishes proportionally.
Second Law of Practical Stellar Physics: a star will produce no radiation except for (1) visible light and (2) a variety of heat that behaves identically to heat convection in an atmosphere, despite the lack of a transmission medium.
Third Law of Practical Stellar Physics: the dangerous or destructive region of a stellar body ends abruptly at the outer termination of its photosphere, except for the heat and light described in the Second Law.
Law of Teleportation: the amount of energy produced when converting matter to energy for the purpose of teleporting that matter to a distant location is an insignificant fraction of the amount predicted by Einstein’s mass–energy equivalence equation; this is a fundamental principle of Convenience Physics.
Law of Technological Complexity: No matter how advanced a technology, anyone who needs to use it will be able to deduce its basic functioning within a few minutes – even if the person belongs to an alien or less-developed culture, or comes from the distant past.
First Law of Aerodynamic Irrelevance: Objects designed to travel solely in space may nonetheless be designed with aerodynamic properties.
Second Law of Aerodynamic Irrelevance: objects designed to travel in solely in space, and which therefore are highly non-aerodynamic, may still travel in an atmosphere as if they were perfectly aerodynamic.
Corollary to the Laws of Aerodynamic Irrelevance (The O’Brien Rule): any object in space that is not designed to alter its velocity, vector or location, such as a space station, may alter its velocity, vector or location through a minor, previously unrealized engineering trick.
First Corollary to Einstein’s Theory of Relativity: Einstein’s Theory of Relativity may be ignored at any time, for any reason; this is a fundamental principle of Convenience Physics.
Second Corollary to Einstein’s Theory of Relativity: when light, or any form of electromagnetic radiation, is employed as a weapon (such as with a laser or blaster), its speed is reduced to approximately 35 miles per hour.
Personal Equivalency Many-Worlds Interpretation of Quantum Mechanics: alternate universes and timelines do not follow the standard laws of contingency – rather, the same individuals will be born in the alternate universe as are born in ours, although their life paths may diverge; this is irrespective of any other changes, major or minor, to historical outcomes.
Ethical Determinism Many-Worlds Interpretation of Quantum Mechanics: alternate universes and timelines do not follow the standard laws of contingency – rather, historical outcomes are determined by the moral choices of the identical version of the visitor from our universe.
Abrams’ Many-Worlds Interpretation of Quantum Mechanics: in an alternate universe or timeline, events will conspire to place equivalent persons into the same social groups they occupy in our universe.
The McFly Rule: If a time traveler prevents a key historical event from occurring, he or she has one week to arrange an equivalent event that will restore the timeline.
First Law of Convergent Evolution: any alien species, regardless of the environment in which it evolved, will morphologically resemble an extant Earth species, albeit with changes in size, color, bodily features and level of intelligence; aliens may also resemble chimera of multiple Earth morphologies.
Second Law of Convergent Evolution: despite the fact that closely-related species from the same planet cannot produce viable offspring, any two humanoid species from different worlds may produce viable offspring that will bear blended traits from both species.
Law of Convergent Visemes: when a technological device is used to translate the speech of a humanoid alien, that alien’s lips and mouth movements will nonetheless appear to match the English speech of the translation.
Omegan Law of Convergent Social Evolution: a humanoid species on a distant planet is likely to pass through exactly the same historical eras, and evolve precisely the same social institutions, as the human civilizations of Earth.
Law of Extraterrestrial Euhemerism: any primitive human superstition is the result of contact with advanced alien technology; this includes psychic powers, magicians, ghosts, angels, fairies, vampires, werewolves, demons, dragons, messiahs and gods.
Law of Technological Trajectory: the more hyper-advanced an alien or future technological artifact, the more likely that it will resemble a large, illuminated crystal.
Law of Irradiated Macrofauna: due to mutations triggered by artificial radiation, animals may grow to enormous sizes normally ruled out by the surface-area-to-volume ratio.
Corollary to the Law of Irradiated Macrofauna: irradiated macrofauna will invariably seek out large human population centers and battle each other.
Influence/Malevolence Relationship in Science: the greater a scientific or technological achievement, the greater the probability that the scientist responsible for it suffers from a mental illness and/or ethical deficit.
Diamond’s Law: an advanced spacefaring species will always oppress, absorb or destroy any less advanced, non-spacefaring species with which it makes contact.
Anthropocentric Exception to Diamond’s Law: an advanced spacefaring species will always oppress, absorb or destroy any less advanced, non-spacefaring species with which it makes contact, unless that species is humanity.
Roddenberry’s Law of Cybernetic Omniscience: any sufficiently advanced computer system will contain the sum all of human knowledge down to the most inconsequential detail, even if the computer was constructed by and for aliens.
Gill’s Law of Alien Impressionability: any humanoid alien species will, upon being introduced to some detail of human history or culture, reconfigure its entire society based solely upon the human example; also known as the Iotian Law.
Law of Atmospheric Inexhaustibility: on a spacecraft, space station or other artificial habitat in a vacuum or near-vacuum, no matter how much air is lost when an airlock is opened or the hull is breached, after the air loss is terminated there will still be sufficient atmosphere to comfortably support the survivors.
Doctrine of Human Psychological Infortitude: any human gifted with transhuman abilities by an alien or future intelligence will initially attempt to perform good works with his or her new-found powers, but will be eventually driven insane and commit destructive acts; also known as the Mitchell Effect.
Doctrine of Hostile Alien Tourism: when technologically advanced spacefaring aliens initiate a war or invasion against the Earth, their first strategic maneuver will be to destroy a number of famous human landmarks, usually ones with no strategic or defensive value.
The Forbin–Cameron–Wachowski Corollary to Turing’s Test of Machine Intelligence: it is possible to demonstrate that a machine has achieved genuine intelligence or sentience, as its first act upon gaining self-awareness will be to attempt the annihilation of humanity.
The Lucas-Asimov-Herbert Model of Human Galactic Societal Development: any vast, galaxy-spanning interstellar human civilization will resemble in many or all respects the empires of the species’ ancient pre-technological past.
And… number 51:
Even’s Revision to Clarke’s Third Law: Any sufficiently advanced technology is indistinguishable from lazy writing.
Feel free to add your own Laws of Sci-Fi Physics in the comments below.