Predicting Weather By The Moon - Xavier University Libraries

Weather By The Moon
and around again. Imagine the inner spinning top is the Earth.
For this is what it looks like. CD is the Earth’s equator.
BOD is the Earth’s tilt. The Earth slides around the Sun
in the plane of AB, tilted all the while. It’s this tilt, CD as
compared to AB, about 23.5 degrees, (measured through
BOD), that gives us our seasons, because the parts of the
Earth at any one time leaning closer to the Sun are having
their summer. The tilt always tilts the same way, and because
it goes around the Sun in the same fixed tilted position,
for half the year the top of the tilt is closer to the sun
and for the other half of the year it is the turn of the bottom
half, which means the Earth spends six months on one side
of the Sun and six months on the other. This tilt is slowly
changing, varying between 21 and 24 degrees and taking
42,000 years for that little variation, which means our seasons
are very slowly getting longer, but that need not concern
us in our discussion about the Moon.
Most satellites that are close to their planets such as
our Moon is, revolve in their planets’ equatorial planes,
that is to say, the Moon would be expected to go around us
at CD. But not this moon. Our satellite ignores the Earth’s
equator and swims merrily along in the same plane around
the Sun as the Earth does, which is AB (the ecliptic plane).
That is because it is more influenced by the Sun and therefore
its orbit around the Sun, than it is by the Earth and its
orbit around the Earth.
However, the Moon’s movement around AB is not in
a flat plane. Have you ever held a dinner plate just above a
table, given it a slight turn and dropped it? If it doesn’t break,
it hits the table and wobbles round and round as it settles
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