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Is it at all possible for complex life to evolve and exist on a planet with rings?

I assume the rings would have to be rock, since if the planet is to support life, it will have to be in the habitable zone of its sun, where ice rings would quickly melt.

My planet is not very different from Earth- it's slightly smaller, so has a little less gravity, but apart from that it's not much different. Life on the planet is pretty much the same as Earth too, with some added magical creatures.

I'm not writing a sci-fi here, but I would like the planet to have rings so that I can write about how different cultures in my world explain the rings, what significance they are considered to have, etc. I'm open to being told what conditions would be needed for a planet to have both rings and inhabitants.

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  • $\begingroup$ Please edit the question to limit it to a specific problem with enough detail to identify an adequate answer. $\endgroup$
    – Community Bot
    Apr 7 at 0:55
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    $\begingroup$ Although we don't have any evidence that a ringed planet could harbor life - we also don't have any evidence that it can't (but we do have evidence that a nearly inconsequential ring can exist around an inhabited planet... 😎). Please keep in mind that a good worldbuilding question would be, "I want my inhabited planet to have rings! Given the following specifications of the planet, is there anything prohibiting the rings?" In other words, tell us the rule you want and let us help you rationalize it. Cheers! $\endgroup$
    – JBH
    Apr 7 at 4:39
  • $\begingroup$ Isn't our moon used to be a ring sometimes in the past? I think it just about stability and composition that it eventually form a moon instead of stay being a ring. To if the condition was just right we may have earth planet with a ring for a long enough. It might be faint line we can see from the ground $\endgroup$
    – Thaina
    Apr 7 at 6:43
  • $\begingroup$ @JBH , thanks for letting me know! I've edited the question now, is there any other information I should add? $\endgroup$
    – mza
    Apr 8 at 21:36
  • $\begingroup$ :-) Well... you didn't change your question in the way I suggested. But you did introduce an issue that begs a question: if your planet has magical creatures, why are you worried about whether or not a planet with natural rings can support life? $\endgroup$
    – JBH
    Apr 9 at 3:00

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Life on Earth has evolved over something like 4 billion years. Saturn's rings probably will last for another 300 million years. As you get closer in to the sun, the three-way gravitational interactions will reduce this lifetime a lot. It depends on the geometry: a moon orbiting in the same plane is stable, but Uranus' moons, which are stuck up at 98 degrees, would not have lasted long in Earth's orbit.

You might have a small ring, such as Mars may have if and when Phobos gets ripped apart by tidal forces in 40 million year time. That will not be dramatic enough to extinguish life. But the ring will be made of rock rather than ice, so the albedo may be nearer our moon.

Putting this all together, you can have rings and life at the same time. But the rings will be there for a tiny fraction of the total period when there is life.

What do you want the rings for? The book jacket? Well okay, provided you have a woman in a skin-tight spacesuit with a ray gun in the foreground to do the 50's sci-fi trope properly.

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  • $\begingroup$ I'd say it's hard to tell if the 1950s were showing women to be stronger and more capable than men except I know better. It's been a long row to hoe and we're not done. $\endgroup$
    – JBH
    Apr 9 at 3:05
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Rings usually form when a smaller body disintegrates while in orbit around a larger one.

This can either happen because of an impact (it is possible that after the impact which led to the formation of our moon, also Earth had rings created by the debris orbiting around it before being captured or expelled) or because of tidal forces (in some thousands of years one of the two moon orbiting Mars will undergo such fate).

The impact scenario for sure is not something which would allow life in the immediate aftermath, while the tidal forces disintegration doesn't bring with it immediate risks. Sure, the fragments making up the rings can fall down, but their size distribution should make so that most of them burns up in the reentry.

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I don't see where problems would arise if the ring system is stable. If it isn't stable, a moon could form and cause gravitational mayhem, or pieces of the rings could fall down to the planet. A really good YouTube channel called Artifexian and they have a video about Earth but with rings. My summary is that rings could help a civilization with advancing in science because by looking at the rings they could find the curvature and size of the Earth along with other things. I am not sure how this would happen, but I think it would be because of them observing how much the ring curves over a known area, then seeing how much it curves over the whole horizon, and this would be for the size of the earth. The video also says that space travel might be harder because rocket ships usually go near the equator to use the Earth's spin to launch out into space. For complex life, it might help because the impact needed to make a stable ring system could help underwater geothermal activities which are usually the culprit for life's evolution. I am not sure how it would effect multi-cellular life, sorry about that.

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  • $\begingroup$ I don't think there's much risk from impacts, since ring particles are usually less than 10 meters across and mostly the size of pebbles or dust specks. Most of them would burn up or fragment on re-entry or land harmlessly. Meteoroids of that size range fall into Earth's atmosphere every day without doing any damage. And presumably these would be concentrated around the equator. Depending on the arrangement of the planet's continents, most of them might land in the ocean. $\endgroup$ Apr 7 at 2:32
  • $\begingroup$ They could also see the planet throwing a spherical shadow on the ring. And the rings would be fantastic build material for a high-orbit industry. $\endgroup$
    – Pica
    Apr 7 at 9:43
  • $\begingroup$ @Pica - that assumes the rings have any significant mass. Saturn's entire ring system masses about 1.5 * 10^19 kg. That's half the mass of the Antarctic ice shelf, spread over a space 80 times the surface area of our entire planet. Not exactly a rich source of anything. $\endgroup$
    – jdunlop
    Apr 8 at 23:19
  • $\begingroup$ Thats enough volatiles to start a inner-system space industry $\endgroup$
    – Pica
    Apr 9 at 7:07

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