[Magdalen] Murdoch

[Roger Stokes]

On 11/09/2015 01:30, James Oppenheimer-Crawford wrote:
> The core will not lose enough velocity of churning to stop the magnetic
> field for the time left between the present and the time when the sun will envelop the earth (vaporizing it entirely).

That may be so but there are periodic reversals of the magnetic field.  
The last happened about 780,000 years ago and the average interval is 
about 450,000 years.  During the switch-over period the strength of the 
magnetic fireld drops to about 5% of the current strength.

Roger