Predicting Weather By The Moon - Xavier University Libraries

Tides
rotation. As Earth’s rotation speed decreases the Moon
must move farther from Earth to conserve angular momentum.
This process is slow. Every 350 years we have to add
another second to the length of our year.
Tides also occur in large lakes, within the solid crust
of the Earth, and in the atmosphere. The latter really are
‘high’ tides!
ATMOSPHERIC TIDES
The Sun is the major source of energy available to
the Earth. At the Earth-Sun distance of 93,200,000 miles
(150,000,000 km) about one two-billionth of the Sun’s outpouring
of energy (mostly in the visible-light range of the
spectrum) is intercepted by us. Most of this is absorbed by
the atmosphere and the solid Earth, giving rise to heating
of the gas of the atmosphere and the rock and water of the
surface.
The heat of the sun heat warms the atmosphere and
the Earth. The atmosphere is a pile of gases 200 miles thick
that, along with the body of water we call the sea, is held to
the Earth by our own gravity. Without this gravity all the
oceans would fly off into space. The atmosphere would go
too.
What does the atmosphere weigh? The total weight
of Earth’s atmosphere is about 4.5 x 1018 kilograms, or
nearly five thousand million million tons. Thus the weight
of the atmosphere per unit area, or its pressure, is about a
ton per square foot at sea level. A layer of water about 10
meters, or 33 feet deep sitting on the Earth at every point,
would exert the same pressure at the Earth’s surface as does
77