Could Ice cause a Pole Shift after all?
The most famous proponent of the “ice cap = pole shift” theory was Charles Hapgood, who in his 1958 book The Earth’s Shifting Crust:
“speculated that the ice mass at one or both poles over-accumulates and destabilizes the earth’s rotational balance, causing slippage of all or much of earth’s outer crust around the earth’s core”
In his 1970 update he changed his mind, and decided that the ice caps could not be the cause, and suggested an unknown internal mechanism of the Earth was responsible.
Ultimately it was a case of the ice caps being too tiny relative to the size and surface of the Earth to make a difference. In fact the relative weights are more akin to a speck of dust on an automobile tyre than anything more serious – and the Antarctic icecap weighs less than one millionth of the entire planet. In these terms the layman can understand why this is unlikely to be the mechanism.
Yet today a reader sent me a news item regarding the Jovian moon Europa:
Curved features on Jupiter’s moon Europa may indicate that its poles have wandered by almost 90 degrees, report scientists from the Carnegie Institution, Lunar and Planetary Institute, and University of California, Santa Cruz in the 15 May issue of Nature.
…The drastic shift in Europa’s rotational axis was likely a result of the build-up of thick ice at the poles. “A spinning body is most stable with its mass farthest from its spin axis,” says Matsuyama. “On Europa, variations in the thickness of its outer shell caused a mass imbalance, so the rotation axis reoriented to a new stable state.”
Now, Europa is 3,000 kilometres (1,900 mi) in diameter, and the smaller the size, the greater the ratio of ice to weight will be, and therefore the greater the effect.
But still, one has to wonder if after all, a simple case of ice accumulation could cause a pole shift. And if that is that case, could NASA and other top bodies to prepare us for such a possibility?
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