The effect of the gravitational force
of the moon and the sun on the earth can be seen in the tides.
Tidal force is the name given to the difference between the
gravitational intensity which an astronomical body creates on the
surface and in the centre of another one.
The difference in gravity which the moon creates on the surface A and
in the centre of the earth B, is the lunar tide, responsible for the
varying level of our seas. The blue zones on the earth in the visual
represent the high tide zones.
