For those of you who don’t know what “sword and planet” is, it’s science fiction in which our lone Earthling hero is thrown onto an alien planet with generally low technology and must fight to survive. Examples include Edgar Rice Burroughs’s Barsoom series (A Princess on Mars, etc.) and some of Jack Vance’s work (particularly the Planet of Adventure series). The excuse for swords being the weapon of choice varies from decaying cultures to alien oppressors.
Recently I’ve been thinking about what I’ll call “sixgun and planet”, basically the same premise but the available technology is closer to the Old West’s. Examples abound, from the anime Trigun to the short-lived TV series Firefly. The question remains, though, why is technology stuck at that phase.
One answer I came up with a long time ago: electronics simply don’t work on the planet’s surface. (My original idea was for a fantasy planet, but this is more interesting.) Any device that relies on an electrical current will malfunction and then stop. Even electric lights and arc welding don’t work. Oddly, though, other electromagnetic phenomena function normally: light transmission, chemical bonds, and nerve impulses, to name three. This has some amusing consequences:
Avionics will fail, so once you land on the planet, you’re pretty much stuck. The only two ways off-planet are miraculous alien technology and launching a rocket with no control circuitry whatsoever, a.k.a. the Wile-E-Coyote method).
The only source of light and heat, apart from the sun, is burning things. Since it’s a different planet, it may not have petroleum. Let’s assume it doesn’t, although it has some equivalent to coal so they don’t have to burn forests.
Ships in orbit can still drop items to the settlers, made with high technology but able to operate in the planet’s weird anti-electronic field. Thus an orbital can manufacture, say, a functional Babbage engine (which was beyond Victorian Age capabilities) and air-drop it to settlers. Likewise, a solar-powered or flame-powered laser could signal said orbital, and a large enough collector could even make a laser cutter (the size of a barn).
Other technologies do work, like optics, chemistry, and biotechnology. A telegraph would use light instead of electrical currents, like the “clacks” in the Discworld series. Genetically engineered organisms may take over some functions of machines, like chemical analysis. Potentially even photonic, psionic, or quantum devices might work as long as they have no electronic parts. So the human population might be very medically advanced, except for delicate surgeries (since heart monitors, etc. won’t work).
One can mix in other genres, like steampunk (those clockwork controls are really precise), supernatural horror (there’s something on this planet that ignores bullets), pulp (daring escapes from alien ruins!), or investigation (“I’m the new marshal, and I’m … from Earth.").
Part of my interest in this setting is figuring out what would work and what wouldn’t. Also one can imagine social stratification based on available technology, from the city-folk who get Babbage engines and the best bio-tech medicines, to the frontiersmen who have only a Winchester, an axe, and an oil lamp. Throw in alien aborigines, ultra-tech artifacts from a forgotten age, and mysterious ultra-terrestrial entities that might be responsible for the anti-electronic field, and you might just have something.