Magnetic Field and Atmosphere
Country: United States
Date: December 2006
How necessary is our magnetic field really for
protecting our atmosphere? Would we really lose our atmosphere if
we lost our magnetic field like in that movie The Core?
The magnetic field is not necessary for preventing
the atmosphere from leaving the Earth; gravity
holds the atmosphere, just as it holds us, to the Earth.
However, the Earth's magnetic field is very important
to the atmosphere in another way. It shields the Earth
from most of the charged particles and radiation from the
Sun, although in severe solar storm conditions there is not
enough shielding to entirely protect satellites, some
communication equipment on Earth, and electric power grid
systems. The magnetic field also directs the streams of
particles from the Sun into magnetic field lines,
resulting in the aurora, as well as enhancement or disturbance
of communication signals beamed through the atmosphere.
David R. Cook
Climate Research Section
Environmental Science Division
Argonne National Laboratory
Our atmosphere is held close by Earth's gravity. Loss of the magnetic
field would not affect gravity and not affect the atmosphere.
Having said that, a collapse of the magnetic field is possible and has
happened many times in the past. In events known as geomagnetic
reversals, the field weakens, disappears and comes back but with the
north and south magnetic poles switched. In other words, the only long
term effect would be that your compass would now point south.
Geomagnetic reversals were instrumental in convincing the Geophysical
community of the reality of continental drift.
While the field weakens and rebuilds in a reversal, Earth's surface is
exposed to more cosmic rays and high energy particles from the Sun and
space. But to my knowledge, there are no extinctions or other notable
events in the fossil record linked to geomagnetic reversals so the
lasting effects seem to be minor.
Oklahoma State University-Okmulgee
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Update: June 2012