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Telling a Planets Age.

  1. Jul 28, 2004 #1
    Just thought of this, probably no validity to it, but just a thought.

    Most planets start with hot cores, they eventually cool, and shrink. Their cooling and shrinking results in more plate tension on the surface because of the shrinkage. This would create more mountain ranges on planets. So, if a planet has many mountain ranges, than someone may surmise that it has cooled and shrunk, and thus, aged. :rofl:
  2. jcsd
  3. Jul 30, 2004 #2
    It seems to me that as a planet ages and its core cools off, tectonic activity would decrease. The mantle wouldn't be as active, and eventually the plates would lose their momentum and fuse. Erosion would then take care of the rest and homogenize the planet's surface.
  4. Jul 30, 2004 #3

    This was the commonly held theory about mountain formation before the 1920s. However, radioactive decay of isotopes in the Earth's core generates heat and it is this which keeps the core molten and makes the tectonic plates move around as they do. Shrinkage had absolutely no effect whatsoever on the present Earth's surface.

    I assume the same was true for Mars and the Moon before they cooled down and solidified.
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