Saturday, September 1, 2018

Polar Opposites

Yesterday's topic included the Antarctic.  Today let's look the other way towards the Arctic Circle.  This is slightly different, as Antartica is a place, and the arctic circle is a parallel - a line of latitude, with the North Pole at its centre.

The Arctic Circle has a significant role in marking the daily patterns of sunlight and darkness. This is where there is the midnight sun and the polar night. Polar night starts to happen at the fall equinox, so they have a little bit of midnight sun to go.

And then there are the Magnetic Poles.  These are locations on the Earth's surface where the planet's magnetic field points straight downwards at the north magnetic pole and upwards at the south magnetic pole. 
An intriguing feature of the poles is that they are always moving; in the case of the magnetic poles, only an average position can be determined.
This from the Canadian Encyclopedia:
"There remains one mystery: every 100 000 years or so, Earth's magnetic field wanes, and the magnetic poles reverse. Volcanic flows provide a logbook of these periodic reversals, because lava remains magnetized in the direction of the magnetic field at the time it cooled. This property provided some of the early hard evidence for the theory of PLATE TECTONICS. Geophysicists speculate that these magnetic flip-flops are due to the chaotic nature of the flow of magma in Earth's core. When will the next reversal occur? There seems to be no pattern, so scientists are unable to make any predictions."

So what if Earth's magnetic poles flip? Will the world end for us?  First of all, it takes between 1,000 and 10,000 years to reverse.  It is a slow process. Scientists say it's the weak in-between phase that would be roughest on Earthlings. What would happen is ozone holes would form due to charged particles bombarding Earth's atmosphere during solar storms.  They could last from one to 10 years. The risk identified would be skin cancer.

The more significant concern is technology. Solar storms can damage satellites, cause power outages, interrupt radio communications.  And then all the species that rely on geomagnetism for navigation - bees, salmon, turtles, whales, bacteria and pigeons.  What will happen, scientists don't know.  What we know is the geomagnetic field is currently weakening.  We could follow more topics on this at 

A grunge abstract for today's theme.

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