From: Donald Nield (email@example.com)
Date: Tue Sep 30 2003 - 18:12:25 EDT
George Murphy wrote:
> Thanks for the references. I suspect that one reason why Barnes & other YECs
> became so smitten with the idea that the decay of the earth's field proved YEC was not
> any observational data but the simple theoretical result that the decay time for a B
> field initially frozen in a highly conducting sphere with dimensions on the order of the
> earth's core is a few thousand years. Of course whether such an elementary model
> represents the real earth very well is another matter!
Could George please check the estimate of the decay time? My back-of-the-envelope
calculation based on data in H. K. Moffat, "Magnetic Field Generation in Electrically
Conducting Fluids", CUP, 1978 (core radius 3500 km, magnetic diffusvity 2.6 m^2 /s) yielded
a time of the order of 10^5 years, which is a bit too long to be useful for the YECs.
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