Cooling History

This is an image the ocean floor of the Earth, showing mountain ranges, subduction trenches, tectonic plastes, and mid-ocean ridges. Click on image for full size version (40K GIF) Image from: U.S. Geological Survey

A planetary body, whether the body is a planet or a moon, has to cool off. The warmth contained inside a body controls what sort of surface activity, atmospheric activity, and interior activity which the body has. As planetary bodies cool slowly, heat diminishes, and the activities diminish to nothing. Examination of a body for various kinds of activities tells scientists what stage a body is in it's history of cooling off.

The heat of a body comes from

• 1.) leftover heat from when it formed
• 2.) radioactive material found in the body
• 3.) outside forces on the body as a whole, such as those which cause tides
• 4.) heat brought to the atmosphere by energetic particles in space
• 5.) warming by the sun