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To: petuniasevan
Seriously though, earth does have two moons. The second one is in a radical polar orbit; some say it is just an asteroid, but its orbit, while not elliptical, is earth-centered.
4 posted on 05/04/2002 6:40:26 PM PDT by RightWhale
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To: RightWhale
Yes, that's true - in a way. However, this "second moon", actually asteroid 3753 Cruithne, is not in a permanently stable orbit. For now, though, its quite elliptical orbit (quite inclined with respect to the orbital plane of the Solar System) has a resonance of 1:1 with Earth, and its oscillation period is somewhere around 760-770 years. However, the orbital stability projections begin to break down in 5000 years and completely destabilize by 10000 years.

A good site for java illustrations of this asteroid and its orbit, compared to Earth and other planets, is this LINK.

In addition, there are now two more near-Earth asteroids known to be currently in resonant states similar to those of Cruithne. These are 1998 UP1 and 2000 PH5.

5 posted on 05/04/2002 7:26:43 PM PDT by petuniasevan
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