This animated image shows heat rising in convection currents from the
outer boundary of the core and cooling at the surface.
How a Planet Cools Off
Planetary bodies cool off by
- 1.) motions inside the body, which bring hot material from deep inside, closer to the surface
- 2.) volcanism, which brings hot material onto the surface
- 3.) circulation in the atmosphere and oceans, where air and water is carried from the warm regions to the cooler regions
- 4.) radiation of heat from the surface, the way an oven radiates heat.
If a planet is small, it can cool much faster to space than can a body which is larger.
Earth has had a long a complicated cooling history. An understanding of the Earth's history might begin with the record of geologic time.
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