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Is this the question thread?


dmjalund

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1.  Compute the heat from accretion of the early Earth.  (This is equivalent to computing the gravitational potential energy of a uniform sphere wi Earth's mass and radius.)

 

2.  Compute the heat release from Earth's differentiation.  (This is, very roughly, the difference between the answer to part 1 and a simple model of the differentiated Earth: a unform core, a sphere of radius 3200 km and density 11 tons per cubic meter, a crust of uniform density 3.5 tons/m3 and a thickness of 50 km, with outer radius = current Earth radius, and the space between those occupied by a mantle of density 5 T/m3.)

 

3. Compute the nuclear energy release in Earth's interior over its history.  Taking the initial bulk composition of Earth found here, look up the half-lives of K-40, U-238, and U-235, and work out how much mass-energy is released assuming each nucleus that undergoes any decay is in the final daughter product; deduct the mass-energy in released alpha particles (if any).  Compute the total energy release from each nucleus, and sum them to get the nuclear energy release.

 

4.  Compare the values in parts 1-3, and the contributions by the three main unstable nuclei.

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9 hours ago, Cancer said:

1.  Compute the heat from accretion of the early Earth.  (This is equivalent to computing the gravitational potential energy of a uniform sphere wi Earth's mass and radius.)

 

2.  Compute the heat release from Earth's differentiation.  (This is, very roughly, the difference between the answer to part 1 and a simple model of the differentiated Earth: a unform core, a sphere of radius 3200 km and density 11 tons per cubic meter, a crust of uniform density 3.5 tons/m3 and a thickness of 50 km, with outer radius = current Earth radius, and the space between those occupied by a mantle of density 5 T/m3.)

 

3. Compute the nuclear energy release in Earth's interior over its history.  Taking the initial bulk composition of Earth found here, look up the half-lives of K-40, U-238, and U-235, and work out how much mass-energy is released assuming each nucleus that undergoes any decay is in the final daughter product; deduct the mass-energy in released alpha particles (if any).  Compute the total energy release from each nucleus, and sum them to get the nuclear energy release.

 

4.  Compare the values in parts 1-3, and the contributions by the three main unstable nuclei.

 

I'm going to show this to my Geology and Astronomy professors this week. I'll let you know what they say. 

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