From: Harvey Newstrom (mail@HarveyNewstrom.com)
Date: Thu Sep 12 2002 - 21:58:59 MDT
On Thursday, September 12, 2002 11:29 pm spike66 wrote,
> Harvey Newstrom wrote:
> > It loops around the earth and the sun in a weird horseshoe orbit.
>
> Im a little puzzled by your discription of the orbit.
> If it passes within 9E6 miles of Earth, the orbit
> around the sun is extremely close to elliptical, and
> the effect of the earth's gravity is very small. My
> back of the envelope calc shows the gravitational
> effect of the sun as over 3000 times larger than the
> effect of the earth at that distance. Cruithne would
> scarcely notice the earth out there.
Your are assuming too much in your "back of the envelope" calculations. It
goes one direction around the sun, loops around the earth and goes back in
the opposite direction around the sun, meets the earth on the other side and
then loops back again. It goes back and forth in a "C" shaped orbit. It
stays on one side of the sun and never gets to the other side. This is what
is so strange. Your elliptical orbit is totally wrong for this weird
object.
See
<http://www.space.com/scienceastronomy/solarsystem/second_moon_991029.html>
for a diagram of the C-shaped horseshoe orbit. (This is old stuff. I'm
surprised you hadn't heard of it.)
-- Harvey Newstrom, CISSP <www.HarveyNewstrom.com> Principal Security Consultant <www.Newstaff.com>
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