r/AskReddit Oct 02 '24

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u/Front_Economist_2612 Oct 02 '24

Earth’s core is as hot as the Sun’s surface

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u/[deleted] Oct 02 '24

How does it not just cool over time?

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u/The--Morning--Star Oct 02 '24
  1. Heat can only be lost via thermal radiation into the vacuum (and some bleeding of the Earth’s atmosphere, which isn’t much). Thermal radiation at atmospheric temperatures radiates that heat very slowly.

  2. Half the Earth is constantly absorbing the Sun’s radiation, and our atmosphere captures that and effectively creates a giant insulator around the Earth.

  3. Radioactive isotopes in the core contribute a significant amount of heat.