• Question: Is it true that in a millions of years time the whole earth will slow down and freeze and why?

    Asked by sophied to Adam, Catherine, Karen, Leila, Nazim on 15 Mar 2012.
    • Photo: Adam Stevens

      Adam Stevens answered on 13 Mar 2012:

      The Earth’s spin is slowing down, because of the moon. There’s a lot of friction from the tides (water mostly, but the rocks also bend a little bit) that are gradually slowing the Earth down.

      In a few million years a day on Earth may be a lot shorter, but I don’t think that will cause the Earth to freeze.

    • Photo: Leila Battison

      Leila Battison answered on 15 Mar 2012:

      The earth’s spin is slowing down, but this won’t affect much more than the length of the day, and even then by much.

      The climate on the Earth is controlled on a long time scale by things to do with the Earth’s orbit, and by how much carbon dioxide there is in the atmosphere. Even though we are going through a period of sudden global warming, the earth will cool down again and fluctuate in temperature. Maybe there will be a very cold time, and maybe there will be a very hot time, but there’s no reason why the world shouldn’t recover.

      Some scientists think that the life on the surface of the earth can help to keep its climate from changing too extremely, they keep it just right for themselves by changing the amounts of carbon dioxide in the air, or how much of the earth is covered in dark, warming plants…

    • Photo: Karen Masters

      Karen Masters answered on 15 Mar 2012:

      In about 5 billion years the Sun will end it’s normal life and expand into a red giant swallowing up the Earth. But that’s not freezing. Have you been reading Arthur C. Clarke? He has a wonderful short story about a world ending by “thermodynamic death” (ie. getting really cold).

    • Photo: Nazim Bharmal

      Nazim Bharmal answered on 18 Mar 2012:

      If the Earth managed to survive the Sun expanding in about 4.5 billion years time, which will probably destroy it, then eventually as the universe slowly cooled down, the Earth would cool too. I don’t know how long it could take, but my guess would be trillions of years, till eventually the universe became the same (cold) temperature everywhere. When I say cold, I mean REALLY cold, nearly -273 deg C.

      As for the spinning of the Earth, I’m not sure about that, but it certainly is slowing: about 200 million years ago, the day was about 23 hours long.

      However, there is evidence the Earth has almost entirely frozen over (the Iceball Earth Hypothesis) due to climate change and that may be “quicker” to happen. And we are due for an ice age, although we might avoid it because of global warming!

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