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Q & A: Effect of polar ice cap melting on length of day

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Most recent answer: 11/21/2011
Q:
If, all the glaciers melted, and the sea level mass around the equator would be much greater, the way the earth rotates might change. Can it flip the location of poles and equator?
- Penny Park (age 25)
Colorado
A:
Gee Penny, I never thought about that problem but your intuition is correct.  The moment of inertia of the earth would increase and since angular momentum is conserved the period of rotation would increase.   I started to make the gory calculation but when searching the web for some facts I stumbled across a site that did it all for me: 

The back of the envelop calculation by Professor Steven Dutch at the University of Wisconsin seems quite reasonable to me.  His answer is the day would lengthen by about 1/2 to 2/3 of a second.
The answer to your second question about flipping poles is 'No. No danger in that'. The amount of angular momentum change needed is way, way too much. 
Thanks for your question.  I learned something.

LeeH


(published on 11/21/2011)

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