The Earth and The Moon

There are two primary types of terrain on the moon. These are;

1. Heavily cratered very old lunar highlands.
2. Relatively smooth and younger Maria.

Tides are periodic rises and falls of large bodies of water caused mainly by gravitational interaction between the earth and the moon.

The earth and the moon are attracted each other, just like magnets are attracted to each other. The moon rises to pull at anything on the earth to bring it closer.

Each day, there are two high tides and two low tides. The ocean constantly moves from high tide to low tide, and then back to high tide.

Gravitational attraction of the moon causes the oceans to bulge out in the direction of the moon. Another bulge occurs on the opposite side since the earth is also being pulled towards the moon (and away from the water on the far side).

Ocean levels fluctuate daily as the sun, moon and earth interact. As the moon travels around the earth, and as they together travel around the sun, the combined gravitational forces cause the world ocean water levels to rise and fall. Since the earth is rotating while this is happening, two tides occur each day.

There are two types of tides:

Spring tides. They occur during the full moon and the new moon. During this time, the earth, the sun and the moon are in a line. The gravitational forces of the moon and the sun both contribute to the tides.

At these times, the high tides are very high and the low tides are very low. These are known as spring high tines and spring low tides respectively.

Neap tide when the sun and the moon are not aligned, the gravitational forces cancel each other out, and the tides are not very high or very low. These are called neap tides.

They occur during quarter moons. During this time, the gravitational forces of the moon and the sun are perpendicular to one another (with respect to the earth).