An overview of the theory which predicts a reversal of the Earth’s geomagnetic polarity.
The paper shows that according to recent research, the earth?s magnetic field has shown signs that it is ready to shift. If this occurs, the magnetic north will point south and the magnetic south will point north and have disasterous effects on Earth. The paper discusses how scientists measure the magnetic field by tracking its history from a gigantic crack in the middle of the Atlantic Ocean that oozes lava. As the lava solidifies into rock, it records the Earth’s magnetic polarity at various times. According to these records, the Earth is overdue for another reversal. The paper shows that prior to a magnetic field reversal, the magnetic field typically grows weaker and weaker until it almost disappears. As a result, the poles flip and strong magnetism starts up again. The paper explains how magnetism levels in ancient pottery indicate that over the past 4,000 years, the magnetic field has weakened by about half. In this century alone, it has decreased by five percent. The paper explores theories put forth by scientists that the Earth’s magnetic field could disappear in the next few hundred or thousand years.
Table of Contents
Origin of the Earth’s Magnetic Field
Theories of Magnetic Pole Reversals
Earth’s Magnetic Field
The Main Field
Electromagnetic Dynamo Effect
Magnetization of Rocks
Processes of Magnetization in Rocks
Morphology of Reversals
Field Direction and Field Intensity
What Drives Reversals?
Core-Mantle Boundary Processes
Over the past three-and-a-half million years, the Earth’s magnetic poles have shifted approximately nine times. This estimate has been found through sampling of the magnetic records formed by rocks in the ocean beds and in ancient lava formations.
Scientists do not know how or why the magnetic poles reverse for sure, nor do they know exactly what effect this will have on life, as we know it. Many believe that the magnetic poles of the Earth reverse an average of every 200,000 years, but the time between reversals has varied widely. The Sun reverses its magnetic poles fairly routinely: essentially every 11 years.