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Disrupted Van Allen Belts...



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> From: "Augustus T. White" <augwhite@neosoft.com>
> Subject: RE: Effects of magnetosphere loss
> Date: Sun, 23 Aug 1998 08:50:42 -0500

> The impact should have been energetic enough to create an ejected plasma of 
> its own -- a sort of solar flare in reverse.  Should have done wonders for 
> particle recruitment!

True, the majority of that material would do one of two things though
because of the gravity field, fall back pretty quickly or else reach escape
velocity (which wouldn't prevent it from crossing the Earths orbit later
since I doubt such an impact would impart solar escape velocity to any of
it. (As a complete aside, if this material was ejected into solar orbit it
should still be there, possibly measurable as the Earth passes through the
cloud each year.) There would also be a gas of this material caught in the
Earths magneto-sphere, though I suspect that synchrotron transport would
eliminate it within weeks. I don't see how this would have necessarily
improved or prevented solar particle take-up unless we posit the field being
changed by the impact as well.

> I'm not sure I follow.  The stripes give us polarity and general direction. 
>  Can you get quantitative information (field strength) as well?  Does this 
> tell us anything about the state of the magnetosphere?

The stripes don't pop out of the ridges in one solid piece. As time goes by
they can be modeled by a oozing (ie slow transport) mass. Now the magnetic
properties (both polarity and magnitude) are set by the external field
strength at the point when the mass cools below the Currie Point (which for
ferrous materials is 600F). So we get both polarity and magnitude
indications in those materials. If the Earths magnetic field is strong that
means that more of those photons (the intermediate vector boson for EM
radiation) would be picked up by those masses and as a result have a
stronger residual field strength. This dependency on external field strength
when it 'crystalizes' (I believe it's really modelled with a spin-glass but
this is sufficient I suspect) is the reason that magnets don't all have the
same strength. It is important to understand that in order for the magnetic
fields caused by the core to get to the Van Allen belt they must pass
through this material and as a consequence they must impart some of the
energy they have to that material (or else we do away with the 3 Laws of
Thermodynamics).

So the short answer is, yes we can deduce relative changes in magnitude by
comparing temporaly ordered sections of these ridges. If we could find a
continous enough piece that went from now back to 65M years ago we could use
this to track the actual magnetic strength of the Earths field over time.

I suspect that given geological activity we can't find that. What we should
be looking for is a stripe that was continous for a goodly period both sides
of the event. It is important to remember that such an event will disrupt
these upwellings as the various plates jossle around as a consequence of the
impact and the ringing in the mantle and lower layers. My first guess is
that the polarity information would be jumbled by movement. This movement
shouldn't effect the relative magnitude however unless the Earths field is
also disrupted - which is what we're after.

> This may turn out to be a very complex process, all of which may add up to 
> little net result.  For example, any loss of magnetospheric blocking of 
> charged particles may be offset by physical blocking by dust in the lower 
> atmosphere during KT+0 to KT+3 (to put a speculative number on it). 
 
The dust in the atmosphere wouldn't provide very much protection against
solar radiation at the levels we currently experience. We could fill the
atmosphere to nuclear winter levels of particulate and then compare the
results, what you will find is that if the Van Allen belt goes away then
anything that doesn't spend great deals of time buried under ground will
dies (which could explain the weight distribution in surviving species since
a T. Rex probably isn't a good tunnel builder and couldn't find enough worms
and insects (scorpions for example can survive at ground zero, they can take
hundreds of times the lethal dose of humans and happily keep on ticking) to
keep it alive.

>   Magnetic storm disruption of the magnetosphere is over in a few days. 

First, the solar magnetic storm doesn't 'disrupt' the magnetosphere strictly
speaking. The only way to do that would be to alter the cycling process in
the Earths core. What we do see is a variation of the levels and shape of
the field in reaction to the solar wind. I am NOT positing a sudden influx
of particles because of a storm on the Sun, that clearly is not reasonable.
What I am positing is that because of the impact the magnetosphere would be
altered considerably and for a good amount of time because the Earth itself
would be disrupted. This *source* alteration at the core would as a
consequence necessarily weaken the field strength allowing the solar wind to
penetrate deeper than normal, so deep in fact that it would impact the
ground without serious interaction with the now weak Van Allen belts.

>  What reason do we have to think this would be a longer term process? 

First, the effect wouldn't have to be long term, a couple of weeks of
elevated radiation would be all it takes to kill all above ground life that
wasn't radiation tolerant within a few months to a year or so. The increased
mutation rate coupled with the radiation induced sterility would also be a
tough effect to recover from. I believe it would be longer termed than that
though. I suspect that it would be months before a reasonable field strength
returned.

The Earth has a lot of mass and as a consequence inertia. If that inertia is
disrupted by some transient it will take a considerable amount of time for
an equilibrium point to be reached. You don't knock something the size of the
Earth up side the head with a big rock that blows a crater 100 miles across
into the air and not expect some rotational anomolies. Those anomolies would
effect the core and as a consequence the Van Allen belt. It literaly can't
be a very short-term process.

>  Changing the *shape* of the Van Allen belts should have little effect on 
> their ability to redirect charged particles, so that the vibrations due to 
> the impact would not be reflected in any long-term inrease in high energy 
> particles reaching the surface.
 
Incorrect, the shape is critical.

The shape of the Van Allen belt without the solar wind is much like a bar
magnet. A sort of weird globe with holes at the poles. The actual teardrop
shape that is seen is a result of drag caused by the solar wind. Reduce that
field strength and that teardrop will reduce considerable and as a result the
amount of em field on the upwind side toward the Sun will become quite small.
If the impact is big enough and the magnetic strength is reduced enough it
won't stop the solar wind on a near perpindicular path with the surface of
the Earth. That radiation hitting the ground would be like a finger from God.

> If this were true, there could never be a beneficial mutation.

Malarky, they would be rare which is just exactly what we see. The proof
that most mutations are inconsequential is demonstrated by the variety of
changes in biochemistry (eg protein folding) between parents and children
that doesn't effect their viability (ie parents have children who have
children and so on). The proof that harmful mutations outway beneficial
mutations is the comparison between birth defects and beneficial changes in
(for example) human speicies. There is a clear ordering:

1.   inconsequential
2.   harmful and debilitating
3.   improvement

This sort of ordering is exactly what one would expect from applying the
laws of thermodynamics to genetics.

> Recall we 
> are, in any case, dealing with a highly disrupted ecosystem undergoing 
> rapid succession.  If there were ever a time when a mutation could find a 
> new niche, this was it.

The vast majority of mutations are such that the embryo doesn't survive to
post partum. The bottem line is that even if a positive mutation would arise
in a small population the disrupted ecosystem (sic) would be such that the
new arrival probably couldn't survive, they need the rest of that ecosystem
to be stable in order to reproduce and express their improvement. This
simply isn't that sort of situation (ie rocks hitting the Earth).


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