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I've been thinking about writing a fantasy novel set on an world with Saturn-like rings. I've been doing some research here by looking up questions about worlds with rings, of which there is a surprising amount. One answer I found indicated that:

The area under the rings will be an exclusion zone because the material will continue to fall to the earth for millions of years. Expect lots of craters and volcanism due to damage to the tectonic plates.

Such a phenomenon isn't mentioned in any other question/answer about rings which I've found, leading me to wonder if it would, in fact, be the case. That answer dealt specifically with the evolution of a ring, which I am not interested in, but it did mention that debris would continue to rain down for "millions of years". It doesn't sound like things will be letting up any time soon. Is the fall of debris just an 'early-stage' thing which will let up after a few million years? The answer doesn't specify.

I don't want a planet with an equator being pulverized by rocks big enough to wipe out nearby civilizations every 20-ish years. So my question is, if an earth-like planet (or simply Earth, for that matter) had Saturn-like rings, would there be any debris-fall beneath them? For all details, assume the rings are identical to the rings of Saturn, just scaled down so the proportions are the same for Earth as they are for Saturn.

Note that I am aware this question has been answered in the question above. This is not a duplicate question, because I am asking whether or not that answer can be backed up/special circumstances explained, due to the fact that no other questions/answers about rings which I have found even mention such a phenomenon.

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  • $\begingroup$ Depends a lot on the rings. How old are they, how they were created, how stable, how big are chunks in them... "any debris" — probably yes, but if it'll be enough to matter? I'm afraid maybe is all you can realistically get without providing more details. $\endgroup$ – Mołot Feb 28 '18 at 16:37
  • $\begingroup$ @Mołot Assume for all purposes that we are literally talking about Saturn's rings here, though obviously on a smaller scale. $\endgroup$ – Thomas Myron Feb 28 '18 at 18:25
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If the Earth had Saturn-like rings, you would not have to worry about falling debris.

As you mentioned, the area under rings that were created (relatively) recently could be hazardous due to falling debris landing on the planet. However, this is not the case for Saturn's rings:

Size of debris: Saturn's rings are mainly composed of particles measuring 1cm to 10m. Nasa claims that any rocks smaller than 25 meters generally burn up in the atmosphere, and that the Earth gets about 100 tons of new space-dust added to the surface every day.

However, because the ring particles will be moving significantly slower than most asteroids, larger amounts of smaller objects/dust would now be landing on the Earth. This actually isn't much of a problem, because of what this extra material actual is.

What the debris is: 99.9% of the material in Saturn's rings is just (frozen) water. Because the melting point of this ice is much lower than the material in rocky-asteroids mentioned previously, the amount of solid ice that will make it to the surface will be very small as most of it will simply melt before it gets too far down.

So, if the Earth (or any planet) had Saturn-like rings, a steady supply of water will be added to the atmosphere with an occasional small meteor making it to the surface. At worst, the upper atmosphere around the equator may be cloudy and the world will be more humid, but there would not be any periodic civilization-ending debris falls. Do note that this only applies to Saturn's old, powdered, watery, stable rings. Newer, rockier, chunkier rings likely would result in more frequent debris landings, as you mentioned, though their speed would be much slower due to coming from orbit.

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  • $\begingroup$ I have been given to understand that rings on an earthlike planet in the goldilocks zone (ie alot closer to the sun than saturn), would result in more rocky debris than icy chunks. They would still be fairly small though. $\endgroup$ – EveryBitHelps Mar 1 '18 at 13:58

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