Okay, first of all, the world I'm building is primarily fantasy-based, which means there is magic around; but for all intents and purposes its only use will be to solve problems faced by the creatures living in it.

This planet originally had three moons. However, it was struck by a gigantic magical disaster which reshaped its surface, razed down most, if not all, of its civilizations and destroyed its third moon, the remnants of which now form a ring of dust around the planet.

My question concerns:

  1. The immediate consequences of a moon suddenly ceasing to be there?
  2. What consequences it would have to a planet which previously had three?

Take in consideration that one of the moons is the same size as ours, the destroyed one is 10% bigger and the other one is 15% smaller


closed as too broad by dot_Sp0T, Mołot, L.Dutch, MichaelK, sphennings Jan 10 '18 at 12:34

Please edit the question to limit it to a specific problem with enough detail to identify an adequate answer. Avoid asking multiple distinct questions at once. See the How to Ask page for help clarifying this question. If this question can be reworded to fit the rules in the help center, please edit the question.

  • $\begingroup$ Welcome to WorldBuilding Enriant! If you have a moment please take the tour and visit the help center to learn more about the site. Have fun! $\endgroup$ – Secespitus Jan 10 '18 at 8:58
  • $\begingroup$ Please have a look at all the questions [there already are on multiple moons](is:q multiple moons) I am positive that many if not all your concerns are already addressed... $\endgroup$ – dot_Sp0T Jan 10 '18 at 9:17
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    $\begingroup$ What @dot_Sp0T was trying to link was a search of is:q multiple moons, which will give you all questions that contain the words "multiple" and "moons". $\endgroup$ – Secespitus Jan 10 '18 at 9:45
  • $\begingroup$ Thanks guys. It's my first question so I'm not used to the rules, but I'm learning them. Besides, I already settled my curiosity on three moons by checking other questions like that $\endgroup$ – Enriant Jan 11 '18 at 6:57
  • $\begingroup$ Good job editing the question, but still you left 2 questions. Don't be afraid of posting more single questions. $\endgroup$ – L.Dutch Jan 11 '18 at 8:16

How would the existence of three moons affect the planet?

The existence of the moons does not affect the planet because it achieves stability. The problems appear after it is gone.

What are the consequences of one of the moons suddenly ceasing to be there?

Once the moon is destroyed the first thing that will happen is a rain of debris that showers one side of the planet. That is the first wave of destruction and is hugely dependent on the size of the moon. Also depending on the distance, the effects are diminished or increased. The further the moon is the less debris will reach the planet and the more debris is burned in the atmosphere as a side effect of the angle of entry.

The second effect is the moons trying to reach a balance again and that will cause very large tides and most likely earthquakes. (And even total planetary destruction if that is not achieved.)

The Third is dust clouds covering the planet.

what are the effects of the new scheme of two moons and a planetary ring?

The tides will most likely be more intense so in the long run sea voyages will be tougher.

The seasons will change slightly. Circadian rhythm and migratory patterns of some animals will be affected.

  • $\begingroup$ Welcome to WorldBuilding! If you have a moment please take the tour and visit the help center to learn more about the site. Have fun! $\endgroup$ – Secespitus Jan 10 '18 at 8:57
  • $\begingroup$ 1. Rain of debris will not fall on just one side of the planet. The cloud of debris typically scatters. 2. Scattering also removes the mascon, that participated in tides' generation. So generally tides will be smaller, unless there were certain orbital correlations, or you meant tsunamis. $\endgroup$ – ZuOverture Jan 11 '18 at 9:15

Nothing out of the extraordinary.

Uranus has thirteen rings and more than three moons (I think five total). So, I'm not sure what you mean by the consequences.

But to be helpful to your story, there could be seasonal variations. Also, if you want you can make the moons fly away: our moon is leaving at 2cm per year, because of the impact that created the Moon makes Earth bulge, throwing it off. Maybe a bigger impact could throw your three moons away or bring them in. Whatever works for your story.

But, yeah, you could look at Uranus or other planets with moons and rings - model them. This is not a rare occurrence.

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    $\begingroup$ I think the reason for the Moon getting away is the tides removing energy from the orbit? $\endgroup$ – L.Dutch Jan 10 '18 at 7:24
  • $\begingroup$ If I recall correctly, Uranus is quite special about its rings. But yeah, any other planet of the solar system with rings, it's not only Saturn. $\endgroup$ – Oleg Lobachev Jan 10 '18 at 7:27
  • $\begingroup$ Jupiter is up to...*checks wikipedia*...sixty nine moons. Jupiter also has four rings. Albeit three of them are extra fine and disperse. If anything, Earth is the oddball (second only to the Pluto/Charon system, which is borderline "double planet"). $\endgroup$ – Draco18s Jan 10 '18 at 8:06

If the ring is dense enough, it might throw a shadow on the surface if the planet has a >0° axial tilt. This might be negligible or it might be enough to change the climate somewhat. The shadow appears on the half of the globe which is tilted away from the sun, so it is likely to make winters harsher in the affected regions.


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