Re: aurora & losing magnetic field

"Dominic-Luc Webb" <dlwebb@xxxxxxxx> wrote in message
news:Pine.LNX.4.44.0509011001110.16955-100000@xxxxxxxxxxxxxxx
|
| I have had interest (amateur) in aurora borealis for some time. At
| my location, near Uppsala Sweden, I have witnessed some of the
| strongest displays ever. At the same time, there are stories
| circulating in the literature and media that Earth is losing its
| magnetic field. The doomsday stories are that, perhaps like Mars,
| this would lead to reduced protection of the atmosphere from
| bombardment derived from solar activity, and at the current rate
| of loss of magnetic field, lethal depletion of Earth's atmosphere
| could occur in about a single millenium.
|
| Seems pretty extreme! I wonder, do people who support this
| doomsday scenaria also believe that solar activity is increasing,
| and that this would enhance the rate of atmospheric depletion?
| Do they have any proposals as to the normal frequency and amplitude
| of variations over the course of many millenia for comparison?
|

There is evidence that the main (dipole) component of the earth's magnetic
field is losing strength and some people believe that a "reversal" will
occur within the next few thousand years.

This could indeed result in more dramatic aurora displays and confusion to
animals / birds which use the magnetic field for navigation.

The good news is that there have been tens, if not hundreds, of these
reversals in the earth's history and the planet is still teeming with life
and has plenty of atmosphere left.

The timescale is such that none of us here are likely to live to see the
critical stages of the reversal. We are just noticing the slow decrease in
magnetic field strength.
--
- Yokel -
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