Geomagnetism - 10 of 21

Geomagnetism FAQs - 21 Found

The strength of the magnetic field has been decreasing lately, does this mean that we are about to have a reversal?

Almost certainly not. Direct historical measurements of the intensity of the geomagnetic field have been possible ever since Gauss invented the magnetometer in the 1830's. Since then the average intensity of the field at the Earth's surface has decreased by about ten percent.



We know from paleomagnetic records that the intensity of the magnetic field decreases by as much as ninety percent at the Earth's surface during a reversal. But those same paleomagnetic records also show that the field intensity has often exhibited significant variation with both decreases and increases in intensity without there always being a coincident reversal.



So, an intensity low does not necessarily mean that a reversal is about to occur. Moreover, the recent decrease in intensity is not really that dramatic of a departure from normality, and for all we know the field may actually get stronger at some point in the not-so-distant future.



Predicting the occurrence of a reversal based upon a knowledge of the current state of the magnetic field is about as easy as predicting the next bull market on Wall Street; you don't know it's happening until it's half over.

Tags: Geomagnetism, Magnetic Field, Monitoring, Sun, Core, Declination, Polarity