Iapetus a moon of Saturn

Iapetus is the third largest moon around saturn and makes it to the 11th place in the solar system. Most notably is probably its two toned look. It has a equatorial ridge and is not in hydrostatic equilibrium.

In fluid mechanics, a fluid is said to be in hydrostatic equilibrium or hydrostatic balance when it is at rest, or when the flow velocity at each point is constant over time. This occurs when external forces such as gravity are balanced by a pressure-gradient force.

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