What would life on Earth be like if it were surrounded by rings?
The Earth really isn’t sufficiently massive. You’re looking for the Roche limit.
Well, we had one at one point but the pieces that stayed in orbit became the moon.
If we had rings, I suspect we’d have ringrise and ringset, with the shadow of the earth visible across them during the early night. That would be really beautiful.
No idea what it would actually be like (other than probably having fewer orbiting artificial satellites). But here is what it would look like… pretty awesome.
So there would be seasons of ring-night round the equators, like the poles. Never thought of that… That would probably change the equatorial climate quite a bit.
The rings of Saturn are somewhat translucent – they’re not solid, and those of other planets are wispy critters, so they wouldn’t cause much of a shadow. Also, there’s no reason I know of (astronomers correct me) that the rings have to be around the equator.
IANAA but would guess that way back when they were formed, the forces that created the ring would be the same that account for the rotation of the earth. They’d form around the rotational axis and thus would ‘settle’ into an equatorial alignment. I believe this is true of all the ringed planets in our solar system though am prepared to be corrected.
ETA and Saturn’s rings do cast a shadow. Quite a significant one.
I doubt it, since from the equator the rings would always be on edge.
There would be no ringrise and ringset, since by definition a ring would be continuous. It’s true the shadow of the earth would be visible across them during the early night, as well as midnight, as well as early morning, just as the shadow of the earth on the moon can be seen all night long (when the moon isn’t full).
But Neptune’s do not.
And there are at least three theories about ring formation that I know of. One is a broken up satellite (think Roche limit violator) another is a capture of some body passing by, then there is a bunch of stuff that never got itself together to make a moon, and that stuff might come from various sources and directions. Not all require an equatorial alignment.
That’s not why the moon has phases. The only time we see the shadow of the earth on the moon is during a lunar eclipse.
:smack:
Okay, point still stands though, you’d see the shadows on the rings between sunrise and sunset, all night long.
(Regarding equatorial climate.)
But the sun is directly over the equator (and thus the rings) only on the equinoxes. The rest of of the time there would be shadows in the equatorial area (just not on the equator itself). Cf. the previously mention shadows of the rings on Saturn.
Ring shine would probably affect nocturnal animals quite a bit. If it out shone the moon, I wonder if moonlight-based cycles would have never been, like turtle migrations and coral reproduction.
I wonder about the effect on astronomy. Would we be able to see the stars? If not, would we ever have grasped our place in the universe? (Yes, the rings would mostly be in shadow at night, but portions would still be visible, and I wonder how much the scatter of light by the atmosphere would still wash out the stars.)
If the rings were blocking the sun, would you be able to look directly at it without destroying your vision?
How would the moon affect the rings? If the moon pulls on the oceans making tides, wouldn’t the same kind of thing happen to the rings? Would the rings have tides?
I’ve been looking on Wikipedia on Earth’s quasi satellites. The last one to temporarily orbit us was 2006 RH[sub]120[/sub] which was in orbit for 13 months and got as close as 0.7 lunar distances. 2002 AA[sub]29[/sub] is predicted to eventually orbit us for 45 years before bouncing out. So it seems that objects can’t stably orbit at a large fraction of the distance to the Moon or further for even hundreds of years. (Lagrangian points aside, which wouldn’t be at all like a ring.)
I haven’t yet come across info on the stability of orbits like geostationary ones. They do seem to last quite awhile if you don’t care about drifting. But the inclination of the Moon’s orbit seems to cause a large amount of latitudinal drift which would disperse a ring in decades into a vaporous “doughnut”.
Lower still, then atmospheric drag on small ring particles would also disperse it.
I can’t see anywhere in Earth orbit where a noticeable ring would have a half life of centuries.
Many of the gaps in Saturn’s rings are thought to be due to the gravitation of Saturn’s moons. The mechanics of it are beyond me, but I expect we’d have a double ring with a clear gap caused by the moon.
If the earth had rings, then we could saw it in half and solve this 4.5 billion year/6000 year argument once and for all.