Thermal History Many of the properties of a planet are controlled by the amount of heat trapped in the interior, and by the rate at which this heat leaks out.
Moon rocks are typically three billion years old or older.
The difference arises because the Earth's mantle is still hot and therefor plastic, so that the surface is constantly being destroyed and rebuilt by tectonic processes. Similarly, Neptune is currently losing more heat than Uranus, indicating that the interior of Neptune is hotter than that of Uranus. The warm core of Neptune is believed to be responsible for Neptune's rather strong magnetic field. Heat Loss Mechanisms Conduction. Heat is the random motion of atoms.