Is the magnet pull on the poles constant or does it fluctuate or even switch?

Question

Is the magnet pull on the poles constant or does it fluctuate or even switch?

Answer 1

The sea floors are slowly spreading due to tectonic activity which releases hot magma at the gaps.  The magnetic particles 'freeze' reflecting the state of the earth's magnetic poles and therefore provides evidence that the poles have weakened and shifted many times in the past (and likely will again in the future).  Ships towing sensitive instruments can identify the many changes (reversed magnetic stripes) on the ocean floors.  the time between shifts is highly irregular (perhaps about 100,000 years on average).

Answer 2

It fluctuates and switches. From careful analyses of directions and intensities of rock magnetisation from many sites around the world it has been established that the polarity of the axial dipole has changed many times in the past, with each polarity interval lasting several thousand years. These reversals occur slowly and irregularly, and for a period of about 30 million years around about 100 million years before present, there were no reversals at all. In addition to full reversals there have been many aborted reversals when the magnetic poles are observed to move equatorwards for a while but then move back and align closely with the Earth's spin axis. The solid inner metal core is thought to play an important role in inhibiting reversals. At the present time we are seeing a 6% decline in the dipole moment per century. Whether this is a sign of an imminent reversal is difficult to say.

Answer 3

it does fluctuate, caused by the flows of molten iron in the core..

It does also switch between North and South Poles, I forget how often but something like every 50,000 years.  We're due for a switch at the moment, scientists are a bit worried as all compasses will be wrong.  Fortunately GPS is more common for navigation these days.

Answer 4

It fluctuates and switches.  It switches every 100,000 years I think, but I could be wrong about that.  When it is in the middle of switching, the earth is exposed to more cosmic radiation and there is an increase in cancer in plants and animals.