A followup question to the one above: If tides are caused by gravity, why is there a difference between the strength of gravity and the ability to raise tides?

Tidal forces are caused by gravity, but there is some difference between
them. Tides are raised because one side of the Moon, for example, is closer
to the Earth than the other. Since the gravitational force decreases with
distance (by 1/distance^2), one side of the Moon is pulled more towards
the Earth than the other. If the Moon were an infinitely small point mass,
then the Earth would still exert a gravitational force on the Moon, but there
would be no tides on the Moon. So the strength of tidal forces depends
on the difference between gravitational forces over the diameter of the
moon or planet. This rate of change is related to 1/distance^3 (the
derivative of 1/distance^2). So the large Sun-Moon distance hurts it
more when looking at tidal forces than in the gravitational forces on the
Moon as a whole. Thanks for your response and I hope this answers your
question.
Jennifer Johnson

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