Fictional Planets

ELEMENT │ PLACE

Fictional planets are large celestial bodies that range broadly in their design depending on the type of fictional world. Hard science fiction settings may feature realistic gas giants and rocky exoplanets, whereas space operas and fantasy settings often feature Earth-like worlds with more familiar biomes. Consideration of the planet’s position in its solar system, the type of star it orbits, and its geological history all contribute to its design. Beyond physical features, fictional planets can harbor societies with cultures, factions, and histories that reflect the environment in which they evolved.


Synonyms: worlds, globes
Example Mythonyms: New Terra, Jensen-Smith III, Tau Epsilon

Designing Fictional Planets

Archetypes

City Planets

Ring Worlds

Toroidal Planets

Tidally-Locked Planets

Overview

Many fictional planets fall into pre-established world archetypes. For instance earth-like worlds are planets that greatly resemble our own but may contain different continents and landmasses. These earth-like planets are frequently used for fantasy settings. Space operas on the other hand, often feature single-biome worlds, which amplify a single region or biome and then layer additional elements on top. Desert planets featuring mesas, mountain ranges, and massive sandstorms are one example of a single biome world.

Earth-like worlds are often used because both designers and audiences are already familiar with the setting, allowing designers to focus on other elements.

Planetary Characteristics

Worldbuilders designing fictional planets should begin with the general characteristics of the planet itself – the composition, shape, size, climate, and other features. Once that is established, other places on the planet’s surface can be designed.

Characteristics
Composition	Earth and earth-like planets are rocky planets. Gaseous planets, ice worlds, and planets composed of fictional materials are also possibilities.
Shape	Planets are defined by having enough mass to turn themselves into a sphere. However, toroidal planets are theoretically possible and in fictional worlds disk worlds and other shapes may exist.
Size	Planets in our own solar system range in size from relatively small (Mercury is 4,880 km / 3,030 mi) to large (Jupiter is 142,984 km / 88,846 mi).
Gravity	Most worldbuilders will keep gravity consistent with Earth’s unless they are designing an alien world.
Orbit	The orbit of a planet around a star (or other central object) determines its’ length of year.
Rotation	The rotation of a planet determines the length of it’s day/night cycle. Longer rotations mean longer days. If the rotational speed and orbit of a planet match, it may be tidally-locked and one side of the planet will always be day while the other will always be night.
Moons and Orbiting Objects	Planets may have moons that orbit them as well as other natural or constructed objects. Consider how many moons a planet may have as well as their own features. Worlds set in a future era may have orbital rings or Kessler belts.
Climate & Biomes	Many fictional planets consist of a single biome such as forest worlds, frozen worlds, or tropical paradise worlds. Others may have an array of regions that mimic Earth or are entirely alien.
Weather	Extreme weather events like planetary storms may be present.
Places of Interest	Planets may have places like cities, alien ruins, or off-world mines. Once the general features of the planet have been established, worldbuilders can now focus on what else lays on the planet’s surface.