From: chris hibbert (chris@pancrit.org)
Date: Sun Dec 15 2002 - 22:36:18 MST
> (The BBC Science Web site writer David Whitehouse
> still has not corrected the 'second moon of Earth' gaff,
> even though our group and other astronomers wrote
> messages to the errors page of that BBC web site and
> asked them to correct that error. The S&T article
> Valeri will cowrite will hopefully address these kinds
> of orbit errors and misonceptions)
A good friend who knows of my interest in Cruithne is Chief Scientist
at the Exploratorium. (http://www.exo.net/~pauld/) He was attending
the American Geophysical Union meeting last week
(http://agu.org/meetings/fm02/ Apparently Cruithne counts as Geophysics.)
My friend said he talked to the people who are into Cruithne, and the
"plausible" justification for calling it a moon is that Earth isn't in
the gap of the horseshoe orbit that Cruithne follows. (!)
If you plot Cruithne's orbit in a frame of reference that co-rotates
with Earth (which you have to do to see the horseshoe) it turns out
that there is a gap in Cruithne's orbit, and Earth's position isn't in
the gap. Cruithne's orbit is highly inclined to the Earth's, which is
why they can still miss one another. I don't see why that makes
Cruithne a moon, but that's the justification that was given.
Chris
-- Chris Hibbert http://discuss.foresight.org/~hibbert chris@pancrit.org
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