The piece you linked to seems to be looking at what earth as we know it would be like if we added rings to our system. It would be different if they have been there from the beginning.
The stuff about nocturnal animmals being affected by light reflected by the rings wouldn't apply to animals which had evolved with the rings in place. Similarly sea creatures would have evolved to cope with different tidal patterns because you probably can't have a large moon.
A moon like ours will disrupt the orbits of the ring particles and cause them to fall out of orbit as meteorites.
I'm trying to figure out HOW the nocturnal animals would evolve... Like, would they be basically nonexistent, or extremely different from what we know? Would it basically be up to me to decide, or is there a semi-concrete hypothesis about how nocturnal creatures would have evolved if we'd had rings?
Do you know how large a moon would realistically be? Or would there be more than one, smaller moons?
My moderately-informed $.02 (I have a BS in biology, but don't much know how rings would affect things beyond broad guesses)
I'm assuming that significant rings would light the sky a bit more than the moon would, but still a lot less than daylight would. This would slightly reduce, but not eliminate, the need for night-time adaptations in nocturnal animals.
You might not have adaptations for complete lightlessness, like sonar (except in cave dwellers). And the difference in eyes between nocturnal and diurnal animals would likely be reduced (they wouldn't need to make as much of a tradeoff between catching every speck of light and color vision). But I'd bet you'd still have some similar adaptations to low-light conditions. Look into cones vs rods, rhodopsin, tapetum lucidum, and the like.
It wouldn't mean extinction for species that actually evolved on a planet with rings - the problems listed exist only for species that are adapted to an environment *without* rings. On a planet with rings, nocturnal species would not be adapted to darkness - at least not in areas where the rings reflected sunlight at night. Similarly, the greater differences between seasons would simply be something accounted for in the biology of the species.
What occurred to me: The compass would never be invented on this planet. Navigation as a whole would be likely to be a very different thing.
Magnetic compasses would still work on a planet without a Moon. Mercury, for instance, lacks a moon but has a magnetic field. And Mars is the opposite: two moons, no magnetic field.
Ah, I had not considered that. On the other hand, compasses work on cloudy days, since humans can orient themselves using the Sun, Moon and stars on Earth (and did use those as navigation aids pre-compass.)
Rings on a planet as warm as earth would have to be made of dust, not ice as with Jupiter and Saturn, so generally a lot less visible since lower reflectivity and no refraction effects. They'd tend to be dark, and often hard to see depending on the angle of the sun and rings.
The moon's effect on tides would be missing - you'd still get tides, since the sun has an effect too, but there would never be unusually high or low tides from the coincidence of solar and lunar tides.
Before someone asks, you can't easily have significant lunar tides and permanent rings on an earth-sized planet, the gravity of the moon would disrupt the rings over time. For planets the size of Jupiter and Saturn the rings are much closer than the nearest big moons, there are also several big moons, so the effect is much less noticeable. Even so there are gaps in those planets' rings where the gravity of moons has pulled in all the dust
( ... )
I'm assuming if I wanted to have ice rings, the planet in question would have to be too cold for human habitation?
If you were to theoretically decrease the size of the moon, or add another, would that have a significant affect on permanent rings/tides? I'm assuming it would, I'm just not sure how.
The more moons and the stronger their gravity, the more difficult it is for rings to stay stable. If you want lunar tides rings are going to have to be small and very close to the planet, and that means that they will have a finite life.
I _think_ you can't have ice rings on a habitable world - they would tend to evaporate this close to the sun - but I can't point you at a definitive source for that.
One thing to be careful of is that the rings block a lot of light, so winters would be harsh. On Saturn, the rings block over 60% of sunlight on the winter hemisphere of the planet. (In fact, in photos, the winter hemisphere looks a different color thanks to changing cloud structures.) Some of that can be mitigated by atmospheric circulation -- but that means storms. (I'm not going into details, since I've never seen people run climate models for 'imagine half the planet gets half the sun it normally gets for large parts of the winter'.)
As others noted, the rings would be darker than Saturn's, but it might be hard to tell -- the Moon is made of pretty dark rock, but we see it as bright as there's nothing to compare it with. You'd also lose a lot of the structure, as Saturn's are sculpted by outer moons.
It would tend to exaggerate the seasons: even on Saturn, the dark side of the densest ring is dark, while the light side is bright. (The other rings don't have this, so it does depend on how much stuff is in the rings.)
(Here's a picture of the unlit side of Saturn: you can see the other and inner parts of the rings glow slightly but the dense middle ring is dark. http://www.fromquarkstoquasars.com/apotd-the-dark-side-of-saturns-rings/. The winter half of the planet would see the rings like this, while the summer half would see lit rings. And both sides of the rings would get really dark around the equinoxes, as the Sun set on the lit half and rose on the unlit half.)
And Little Details marked a comment I left as spam, so...
It would tend to exaggerate the seasons: even on Saturn, the dark side of the densest ring is dark, while the light side is bright. (The other rings don't have this, so it does depend on how much stuff is in the rings.)
If you find a picture of the unlit side of Saturn: you can see the other and inner parts of the rings glow slightly but the dense middle ring is dark. The winter half of the planet would see the rings like this, while the summer half would see lit rings. And both sides of the rings would get really dark around the equinoxes, as the Sun set on the lit half and rose on the unlit half.)
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The stuff about nocturnal animmals being affected by light reflected by the rings wouldn't apply to animals which had evolved with the rings in place. Similarly sea creatures would have evolved to cope with different tidal patterns because you probably can't have a large moon.
A moon like ours will disrupt the orbits of the ring particles and cause them to fall out of orbit as meteorites.
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I'm trying to figure out HOW the nocturnal animals would evolve... Like, would they be basically nonexistent, or extremely different from what we know? Would it basically be up to me to decide, or is there a semi-concrete hypothesis about how nocturnal creatures would have evolved if we'd had rings?
Do you know how large a moon would realistically be? Or would there be more than one, smaller moons?
Reply
I'm assuming that significant rings would light the sky a bit more than the moon would, but still a lot less than daylight would. This would slightly reduce, but not eliminate, the need for night-time adaptations in nocturnal animals.
You might not have adaptations for complete lightlessness, like sonar (except in cave dwellers). And the difference in eyes between nocturnal and diurnal animals would likely be reduced (they wouldn't need to make as much of a tradeoff between catching every speck of light and color vision). But I'd bet you'd still have some similar adaptations to low-light conditions. Look into cones vs rods, rhodopsin, tapetum lucidum, and the like.
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What occurred to me: The compass would never be invented on this planet. Navigation as a whole would be likely to be a very different thing.
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The moon's effect on tides would be missing - you'd still get tides, since the sun has an effect too, but there would never be unusually high or low tides from the coincidence of solar and lunar tides.
Before someone asks, you can't easily have significant lunar tides and permanent rings on an earth-sized planet, the gravity of the moon would disrupt the rings over time. For planets the size of Jupiter and Saturn the rings are much closer than the nearest big moons, there are also several big moons, so the effect is much less noticeable. Even so there are gaps in those planets' rings where the gravity of moons has pulled in all the dust ( ... )
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If you were to theoretically decrease the size of the moon, or add another, would that have a significant affect on permanent rings/tides? I'm assuming it would, I'm just not sure how.
Thanks for the info!
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I _think_ you can't have ice rings on a habitable world - they would tend to evaporate this close to the sun - but I can't point you at a definitive source for that.
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As others noted, the rings would be darker than Saturn's, but it might be hard to tell -- the Moon is made of pretty dark rock, but we see it as bright as there's nothing to compare it with. You'd also lose a lot of the structure, as Saturn's are sculpted by outer moons.
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(Here's a picture of the unlit side of Saturn: you can see the other and inner parts of the rings glow slightly but the dense middle ring is dark. http://www.fromquarkstoquasars.com/apotd-the-dark-side-of-saturns-rings/. The winter half of the planet would see the rings like this, while the summer half would see lit rings. And both sides of the rings would get really dark around the equinoxes, as the Sun set on the lit half and rose on the unlit half.)
Reply
It would tend to exaggerate the seasons: even on Saturn, the dark side of the densest ring is dark, while the light side is bright. (The other rings don't have this, so it does depend on how much stuff is in the rings.)
If you find a picture of the unlit side of Saturn: you can see the other and inner parts of the rings glow slightly but the dense middle ring is dark. The winter half of the planet would see the rings like this, while the summer half would see lit rings. And both sides of the rings would get really dark around the equinoxes, as the Sun set on the lit half and rose on the unlit half.)
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