Dynamics of an Earth Ring

Ian Stirling wrote in message news:41601991$0$17957

Google "how the moon was formed".

Thanks Ian. The first hit gives me this link, which is very
interesting:-

http://csep10.phys.utk.edu/astr161/l...formation.html

Here they list 5 possible ways the Moon could have formed:-

1. The Fission Theory: The Moon was once part of the Earth and somehow
separated from the Earth early in the history of the Solar System. The
present Pacific Ocean basin is the most popular site for the part of
the Earth from which the Moon came.

2. The Capture Theory: The Moon was formed somewhere else, and was
later captured by the gravitational field of the Earth.

3. The Condensation Theory: The Moon and the Earth condensed together
from the original nebula that formed the Solar System.

4. The Colliding Planetesimals Theory: The interaction of
earth-orbiting and Sun-orbiting planetesimals (very large chunks of
rocks like asteroids) early in the history of the Solar System led to
their breakup. The Moon condensed from this debris.

5. The Ejected Ring Theory: A planetesimal the size of Mars struck the
earth, ejecting large volumes of matter. A disk of orbiting material
was formed, and this matter eventually condensed to form the Moon in
orbit around the Earth.

Apparently, in that web article, the fifth hypo (Ejected Ring Theory)
is the *most* favoured. On a first thought, I personally find that to
be the LEAST likely. It just does not 'fit', somehow... Anyone have
any other preferences?

Abdul