The deepest mythological archetypes in my Earth-like world hint at a wondrous and terrible disaster in the ancient past. ~10 tya a celestial body (perhaps a small, second moon, or a wandering asteroid, either suits) broke apart in the sky, well in sight of my primitive humanoids, and formed a beautiful terrestrial ring around the planet.

Is it possible that humanoid life survives what I presume would logically be a period of acutely raised meteoric activity? I am a layman to planetary physics, but I shall try to enumerate relevant details:

  1. Assume all unmentioned characteristics mimic Earth.
  2. My humanoids do not have any special advantages over humans to help them survive meteor impacts or the plantery changes that follow large meteor impacts.
  3. Assume, however, that they are prodigously lucky at the very last moment. If there is "a chance" that a significant portion of the population lives by some unorthodox move, like going underground, they do.
  4. Ultimately, the real question is, is there "a chance" that a significant portion of the population survives. Not just a few dozens or hundreds across varied continents, but enough that 10,000 years after the event, they're capable of a regrowing into resembling medieval society?
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    $\begingroup$ 10, 000 years is a long time even a group of less then a dozen could completely repopulate the earth given that, assuming that inbreeding didn't wipe them out. $\endgroup$ Commented Sep 25, 2023 at 17:22
  • $\begingroup$ Humanoids survived the Chicxulub impact, which may have destroyed the dinosaurs in as little as 33,000 years. Knowing this, is 10,000 years sufficiently long period? It's a detail, and probably wouldn't change a good answer, but it's not a myth if it's trivial to ascertain from the geological record, which a scant 10,000 years would permit. $\endgroup$
    – JBH
    Commented Sep 25, 2023 at 18:50
  • $\begingroup$ Would humanity survive the formation of a Planetary... it actually doesn't matter what you put after, that the answer is always, no. $\endgroup$
    – John
    Commented Sep 25, 2023 at 22:46
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    $\begingroup$ @JBH: No humanoid anything survived the Chicxulub impact. Our ancestors were small nocturnal (or maybe burrowing) insectivores at that time, somewhat similar to modern shrews. $\endgroup$
    – AlexP
    Commented Sep 26, 2023 at 1:18
  • $\begingroup$ @AlexP You're correct, I was completely in error, but I'm delighted with a new study from the University of Washington that suggests a small primate did exist and survive that time - I think that's what you're talking about. $\endgroup$
    – JBH
    Commented Sep 26, 2023 at 1:30

1 Answer 1


I think you are glossing over the points that would actually cause the extinction event.

You can probably engineer some sort of trajectory for your quasi-Theia such that it won't immediately shower the planet with debris. So suppose there is such a configuration, where the incoming protoplanet breaks apart due to the Roche limit and only a insignificant fraction of debris immediately enters the main planet's atmosphere. All you have really done is move the date of the end a few years out.

Planetary disks are inherently unstable, even more so if it is made up of hot debris in irregular orbits.

To gloss over some physics, the internal friction of this thick disk will be enormous and slow it down as a whole. So all this debris is just gonna crash down on the planet regardless. Whatever fraction of the original incoming protoplanet the disk is made of, most of that will rain down very quickly after the initial event.

I think, if you want the visuals, a better approach would be to have some moon be very active to the point where it generates a disk made up of ash and dust. Visually that will look somewhat similar, but does not come with the whole extinction stuff.

  • $\begingroup$ Thanks for the insight. Is there anywhere I can learn more about what a "moon dust" ring would look like? How it would form? How long it would stick around? $\endgroup$
    – Fictotum
    Commented Sep 25, 2023 at 18:41
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    $\begingroup$ @Fictotum Saturns rings are made by Cryovolcanic activity, so i imagine the processes should be the same. In your case, the only difference is that it would be "hot" Volcanos because an Ice moon cant really exist inside the habitable zone of a star. As for how long it would last, well for however long the moon is geologically active +- a few 100000 years. $\endgroup$
    – ErikHall
    Commented Sep 25, 2023 at 18:49
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    $\begingroup$ @ErikHall cryovolcanic activity of one of it's moons. just to clarify for OP, the planet itself could be completely earth-like en.wikipedia.org/wiki/Rings_of_Saturn#E_Ring $\endgroup$
    – Hobbamok
    Commented Sep 26, 2023 at 8:19
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    $\begingroup$ @Blueriver I dont know. From experience working with simulations of that caliber, id say i dont know without know the initials. All i can tell you is the rings wouldnt last very long. $\endgroup$
    – ErikHall
    Commented Sep 26, 2023 at 13:32
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    $\begingroup$ @ErikHall I'd argue that makes your answer even better then, since it leaves a lot of wiggle room to OP without losing credibility! $\endgroup$ Commented Sep 26, 2023 at 18:29

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