[meteorite-list] INNER SOLAR SYSTEM

From: Rob McCafferty <rob_mccafferty_at_meteoritecentral.com>
Date: Mon Sep 25 15:44:00 2006
Message-ID: <20060925194358.16001.qmail_at_web50901.mail.yahoo.com>

In light of the recent suggestion that Neptune began
inside Uranus' orbit and that the outer planets
migrated to their current positions, I find it very
eay to believe that the motions of our planets are not
as neat and tidy as we were all taught to believe at
school.

A few years ago, I read that no 3 body situation is
ever truly stable. I suppose the same myst also be
true of an 8 body one(or 9 if you didn't like the
IAU's decision).

I'm not inclined to believe the thought of them being
wobbling plates and something necessarily setting them
in their motion. There's no reason for it to have been
formed evenly and less of a reason to it remain so.
I'll be intrigued to see how these theories develop
over the years.
This is truly a fascinating time for astronomy.

Rob McC

--- Pete Pete <rsvp321_at_hotmail.com> wrote:

> Wow!
> Almost chaotic, in this animation!
> But as you say, harmony.
>
> Considering how this solar system is believed to
> have formed, do you think
> that these dynamics are something that could be
> expected in other systems,
> too?
> What could have kick-started it? Only the Sun,
> somehow, right?
>
> Or would you think that some past near-catastrophe
> could have spun the
> plates? (one of them there new-fangled wandering
> stars)
> It is just a little difficult for me to imagine
> these wobbles were borne
> without an outside influence.
>
> Cheers,
> Pete
>
>
>
>
> From: "Sterling K. Webb"
> <sterling_k_webb_at_sbcglobal.net>
> To: "Meteorite List"
> <meteorite-list_at_meteoritecentral.com>
> Subject: [meteorite-list] INNER SOLAR SYSTEM
> Date: Sun, 24 Sep 2006 20:56:27 -0500
>
> Hi,
>
> We all know the orbits of the planets vary
> slightly. The
> obliquity, or tilt of the Earth's axis oscillates
> from 22.1?
> to 24.5? in a 41,000 year long cycle, as does
> orbital
> inclination, and the orbit's eccentricity has a
> small variation
> over a 102,000 year cycle from almost zero to 0.070.
> The
> equinoxes precess in a 23,000 year cycle. As you can
> tell, these numbers don't change that much, so
> things
> should appear to be pretty calm.
>
> The other planets in the inner solar system go
> through
> similar cycles, equally non-dramatic, although I
> vaguely
> remembered that Mars was a bit more extreme than the
> rest of us. It doesn't seem like it would be very
> dramatic
> or exciting to watch, if you could watch it change.
> Then,
> I watched this movie of the inner solar system's
> orbital
> evolution over the last 3,000,000 years:
> http://muller.lbl.gov/pages/innerplanets.html or
> directly
> from here: http://muller.lbl.gov/images/inner.mov
>
> The movie that you can view or download from
> this
> page is about 12 Mbytes long, and in .mov format. I
> used QuickTime Player (.mov is its native format)
> because
> you can step through it frame by frame (right/left
> arrows).
> Real Player and Windows Media Player (10) will also
> play it.
>
> The scale of the animation is not exaggerated or
> amplified.
> If you could sit in space and watch the inner solar
> system
> trace each orbit with a visible line, this is what
> you'd see.
> The units on the edges of the background plane are
> AU's.
> The site rather modestly says, "Even if you are an
> expert,
> you may be surprised at what you see!"
>
> "Astounded" is more the word that comes to my
> mind.
> "Drunk drivers at NASCAR track" would be a good
> title,
> if you pasted in some little cartoon racers with
> sponsor
> patches. Is this the renowned "stability" of the
> solar system
> we hear so much about?
>
> And, of course, it IS stable. Nothing has gone
> wrong in
> the last three million years nor for a long time
> before that.
> Still, everything wobbles like crazy...
>
> Currently, Venus can approach as close as 24.7
> million
> miles and Mars as close as 34.7 million miles, but
> it would
> seem that in the past (and future too) their close
> approaches
> could be as near as roughly half that distance.
>
> I found this movie to be utterly fascinating
> (could be just
> me). After a few times through it, I would
> concentrate on
> just watching one planet at a time: Mercury slides
> back and
> forth like it was shifting the Sun from one
> elliptical focus
> point to the other; Mars' orbit expands and
> contracts; Venus
> and the Earth pull up close and flirt with resonance
> lock; they
> all rock back and forth.
>
> As with any good movie, I was disappointed that
> it was
> "only" three million years long.
>
>
> Sterling K. Webb
> ----------------------------------------
>
>
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Received on Mon 25 Sep 2006 03:43:57 PM PDT