If the sun was extinguished or there was a permanent worldwide eclipse, how long would it take for us all to freeze to death, and is there anything we could do to stay alive?
• A back-of-the-envelope calculation suggests the whole Earth might freeze solid within 45 days, radiating away its thermal energy according to the Stefan-Boltzmann law, which relates energy loss of a body to its temperature. My calculations assume the vast bulk of the Earth's captured solar energy is stored in the oceans, which have an average temperature of 15 °C down to a depth of 35 metres. Energy carried by water at greater depths doesn't count because it would rapidly become isolated from the surface by ice floes.
With its smaller heat capacity, the land would freeze much more quickly than the oceans. Air over relatively warm oceans would rise, pulling in cold air from the continents. ...
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