These world building prompts come from 3000 World Building Prompts, which you can get at Amazon. This section is focused on creating planets and moons, including habitable ones.
Planets
- What is the name of the galaxy?
- What is the solar system’s name?
- Are there any comets and how often do they appear?
- Is there an asteroid field?
- If so, in between which planets is it found?
- How hard is it to pilot through it?
- Are there any destroyed planets in this system?
- If so, is the planet in pieces?
- Or is just devoid of livable conditions now?
- What kind of sun (yellow, red dwarf) is at the system’s center?
- Is it a binary star system?
- How many planets are in the solar system?
- Which planet are you creating (nearest, farthest, fourth)?
- Does the planet have a ring system (like Saturn)?
- Is the atmosphere breathable?
- Is this a rocky, icy, or gaseous planet?
- How many seasons are there and how often do they occur?
- Is the planet in a retrograde orbit of the sun?
- Does the planet rotate clockwise or counterclockwise?
- Are there other planets in the solar system?
- What do they look like to the naked eye from this planet, if they can be seen?
- How many planets are in the sun’s habitable zone?
- Can other planets be seen with the naked eye?
- Can other planets be visited via magic or technological means?
- Are any constellations important in your setting?
- Which constellations are visible in each hemisphere?
- Are there are dark constellations?
- Are there constellations associated with months, like astrological signs?
- Is this planet bigger or smaller than Earth and by how much?
- Has global warming occurred and to what degree?
Moons
- How many moons are there?
- Are any of the moons tidally locked?
- Is the planet and one moon tidally locked to each other?
- Are any moons in a retrograde orbit?
- Are any moons barren?
- Are any moons icy?
- Are the tides the moon(s) cause bigger, smaller, or the same as on Earth?
- How many moons are causing the tides? If more than one, how often do the biggest tides occur?
- Are there any conjunctions of moons, planets and the sun(s) and how often do these occur?
- Are any moons habitable? Which ones?
Habitable Moons
- Is the world you’re creating right now a moon?
- If so, what effect(s) does the planet have on it?
- How often does the planet cast its shadow over the moon in a penumbral eclipse?
- In a total lunar eclipse?
- In a partial lunar eclipse?
- How dark does it get during each of these eclipse types?
- For how long does this occur?
- Are there any natural events that take place then, such as creatures who only come out at that time?
- How does this impact sentient life on the moon?
- Are there any rituals or protections people plan for and make?