MadSci Network: Earth Sciences

Re: Is there a way to get rid of the the magnetic field sourrounding our earth

Date: Mon May 30 00:36:22 2005
Posted By: David Dunbar, Staff, Geophysics, GeoCenter, Inc.
Area of science: Earth Sciences
ID: 1111680198.Es


The short answer to your question is no. The earth's magnetic field is
believed to be due to complex convection patterns in the outer core. These
are driven by the heat of radioactive decay, accretion energy from the
formation of the earth and the energy given off as the material at the base
of the outer core freezes to the inner core. The energy driving the
convection will eventually dissipate and the earth's field will go away.
This will take several billion years. Do a web search on “geodynamo”. 

 The earth's magnetic field is complicated and changing. The simplest
description is that of a dipole (or bar magnet) that is off center and
tilted relative to the spin axis of the earth. Like many simple
descriptions, there are a lot of details that get overlooked. For one, the
magnetic poles are moving. For another, the strength of the field has
dropped by roughly one half since Roman times. Since reliable direct
measurements were first made around 1845, the strength has dropped by 10%.
This has prompted speculation that the magnetic field may be starting a

The magnetic field offers some protection from charged particles from the
sun. Having the magnetic field go away is probably not desirable. The
details of a reversal are not sufficiently well known to say if the field
strength would go to zero at some point. The geodynamo models generally
indicate this won't happen. It appears that the poles will split into
several poles and migrate to the opposite hemisphere over several thousand
years. However, in the absence of detailed knowledge of what happens during
a reversal, a proposal was made that could approximate what you are
suggesting. The object of the proposal was to use current carrying coils
going completely around the world at several latitudes to maintain
something like the current dipole field. This would literally be the
largest structures ever made. Reversing the current flow would reduce the
field instead of maintaining it.


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