The gravitational force on the Earth due to the Sun is greater than that due to the Moon. However, t

Question

The gravitational force on the Earth due to the Sun is greater than that due to the Moon. However, the tidal effect of the Moon's pull is greater than the tidal effect of the Sun. Why?

Professor PC Thomas Classes · Answer

Gravitational force is proportional to $1/r^2$, but the tidal force (which is the difference in gravitational force across the Earth) is proportional to the gradient of the gravitational field, which scales as $1/r^3$. The much smaller distance to the Moon makes its $1/r^3$ factor dominant over the Sun's.