Predicting Weather By The Moon - Xavier University Libraries

Tides
is always a corresponding high tide on the earth’s opposite
side. About two centuries ago it was assumed that when the
moon was on one side of the earth, it pulled the centre of
the earth away from the sea on the other side, leaving a big
hole into which the sea flowed back, causing a high tide
there. The trouble with that idea was that the moon pulls on
all parts of the earth. As it also pulls on the sea it could
also be said that the sea gets lower on the opposite side of
earth to the moon, and therefore a lower tide should result.
Then somebody tried to explain it away by blaming
centrifugal forces.
The idea came from the thought that centrifugal forces
explained why the atmosphere was higher at the equator
than at the poles, the idea being that it was ‘thrown out’
more as the earth rotated. The ‘troposphere’ is that lower
region of the atmosphere, where the higher you go the
cooler it gets. The troposphere is highest at the equator,
being on the average about 18 km. high there. It is lower in
the moderate latitudes, and only 4-6 km. high above the
ground at the poles. The weight of the atmosphere is constantly
changing as the changing barometric pressure indicates.
Yet one would imagine centrifugal forces to be constant.
The height of the atmosphere also is continually
changing, as a daily lunar air tide would suggest.
It was worked out that the atmosphere rotates with the
same angular velocity as the earth and behaves like a fluid,
and using the known maths of centrifugal force it was calculated
that Earth’s polar and equatorial axes must be about
35,000 and 52,000 miles respectively; and so at the equator
the atmosphere must extend more than. 21,000 miles
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