Re: What The Earth Would Look Like With Rings Like Saturn
Hactar
John Hatpin <RemoveThi...@gmailAndThisToo.com> wrote:
> Hank Gillette wrote:
>
> > There would be other effects. It would never be completely dark. It
> > might even be brighter than having a full moon.
>
> And the moon's still there.
According to a theory I read on the origins of the moon, a Mars-sized
planet collided with the Earth knocking out enough mostly-mantle to form
the moon, plus some rings. The rings fell back into the atmosphere,
which is why they're not there now. I don't believe the gravitational
environment has changed that much so that if the rings didn't survive
_then_, they probably won't survive _now_. Unless there's a critical
radius, inside which rings cannot survive. It's like installing an
Earth-pressure atmosphere on $planet_without_much_atmosphere --
technically you can probably do it, but it won't stick around.
> What about gravitational effects, and tides? Would that be
> significant? We'd all be several pounds lighter, but leaning at a
> slight angle towards the poles to compensate.
I don't see how we'd be any lighter net. My intuition says the rings
would add as much force pulling us up as they would add pulling us down.
> > I don't think it would be a good thing.
>
> I disagree, it would be fun. It's a great idea.
Spaceflight would be interesting in the same way Russian Roulette is
interesting.
--
-eben QebWe...@vTerYizUonI.nOetP royalty.mine.nu:81
If you need someone to blame
Throw a rock in the air
You'll hit someone guilty -- U2, _Zooropa_, "Dirty Day"
Mike Williams
>According to a theory I read on the origins of the moon, a Mars-sized
>planet collided with the Earth knocking out enough mostly-mantle to
>form the moon, plus some rings. The rings fell back into the
>atmosphere, which is why they're not there now.
I thought that those rings formed the Moon. Because those rings were
well outside the Earth's Roche Limit, the particles were able to
aggregate together. The rings in that presentation were positioned
inside the Roche limit, so the particles can't aggregate together. The
tidal force from the Earth on any aggregate of particles exceeds the
gravitational force trying to hold the aggregate together.
I'm not sure how stable Saturn's rings are now considered to be. Before
we knew about shepherding moonlets, theory said that they should only
last a few tens of thousands of years. The shepherding moonlets increase
the stability, but I suspect that that probably doesn't give stability
over billions of years. In astronomical terms, rings are fairly
transient phenomena.
--
Mike Williams
Gentleman of Leisure