Thursday, 7 July 2011

North Pole on the move.

The North Pole has been in the news lately, moving 40 miles per year in the direction of Siberia.  This is a normal sort of motion although some airports have had to  repaint their runway markings to update directions.
The big move comes every couple hundred thousand years when north and south poles break up into several poles for a time and then settle down with south and north reversed.  The switchover takes more than a thousand years and is unlikely to endanger lives.
How can they know this?  One way is looking at magnetic iron specks in rock near the spreading mid- atlantic ridge under the ocean.  In ancient times they emerged in molten rock, lined themselves up with the magnetism of the day and soon after were frozen into place. At certain distances away from the spreading ridge, the tiny poles of those magnets point opposite to modern day ones.  Left behind in the sea floor is a map of this story.
    This began to show up in school curricula in the 90's.  What a crop of science keeners we would have if schools pointed you to what we don't know now instead of what we are pretty sure of.  A life that comes up with one good question is a life worthwhile.

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