[meteorite-list] Re: Crackpot Theory Redux

From: Axel Emmermann <axel.emmermann_at_meteoritecentral.com>
Date: Mon Oct 31 18:34:56 2005
Message-ID: <KKEDKELDHEAGAPEINLODAEHMCNAA.axel.emmermann_at_pandora.be>

Hi Sterling and list,

thanks for clearing that up.
The physics that govern high velocity impacts seem to have a something in
common with quantum physics... the are not quite to be approached with the
garden-variety logic ;-)))

Maybe a last one before bedtime:

Upon implosion of the stellar core of a supernova, the magnetic field would
increase dramatically in strength. Would that not cause the ionized matter
( I gather that pretty much every atom within the start system would be
ionized at the time of the explosion and shortly thereafter ;-))) to be
concentrated along the field lines?
I mean, the magnetic field would start expanding with the speed of light in
less than a second after the blast but the expanding shell of debris would
have to be considerably slower and hence fall under its influence, or am I
seeing this wrong?
Wouldn't some of that matter coalesce while it crashes into the interstellar
matter? Maybe there's more substantial matter in a SNR than just ions?
Probably not enough to account for cataclysmic events on earth but just for
the sake of argument?

Axel



-----Oorspronkelijk bericht-----
Van: Sterling K. Webb [mailto:kelly_at_bhil.com]
Verzonden: zondag 30 oktober 2005 20:49
Aan: Axel Emmermann
CC: Meteorite List
Onderwerp: Re: [meteorite-list] Re: Crackpot Theory Redux


Hi, Axel, List,


    Hitting the atmosphere at very high speeds
generates a plasma of very high temperature.

    "Normal" re-entry plasma temps are 3000
degrees for carefully controlled orbital re-entry.
For the "normal" meteoroid re-entry, temps are
15,000 degrees (or more). For the high speed
particle, expect 50,000 to 200,000 degrees
within a millisecond.

    At these temperatures, the black body
spectrum contains major intensities in X-Ray
and even gamma frequencies. These very effectively
transfer the energy of the plasma to the body
of the particle.

    The result, within another few milliseconds,
is a cartoon noise: "Pfooot!" The "particle" is
gone. What remains is mostly slow-moving iron
ions, drifting away on the thin exosphere...

    The vast majority of cosmic rays are protons.
The big nuclei create a cascade of particle
transformations that end in a flurry of photons
and neutrinos. The most effective detectors for
high mass cosmic rays are flash detectors and
deep neutrino detectors.

    Interesting (to me, anyway) is the fact that
the heavy high speed nuclei have experienced so
much relativistic increase in mass that a nuclei
whose "weight" is a laughable concept will bulk up
until it weighs as much a good sized bacterium!

    Back to iron particles from supernovas:
The collapse of a star that masses many times
the mass of our Sun into a Type II supernova
takes place in less than a second! So the event
that creates the iron nuclei is effectively
instantaneous.

    The nuclei all have the same mass; they
all experience the same energy accelerating
them. So velocities are initially very uniform,
and the expanding shell of particles is very
thin and precise. Even after several light
years of travel the shells remain pretty well
defined.

    The density of iron particles encountered
depends entirely on the distance to the supernova.
Initially Knie and Hillebrandt guessimated the
supernova that produced "their" 60-Fe at 90 to
125 light years away. Then, refining the results,
they came up with about 75-90 light years away.
The more recent berylium-10 results suggest the
explosion was closer. Now, they are more cautious:
25 to 75 light years away.

    Since the density of particles depends on the
inverse square of the distance, cutting the estimate
from 125 light years away to 25 light years away
increases the density 25-fold! Big difference.

    You raise an interesting point about a heat
flash from re-entering particles at high density.
I don't think so, but it's like the chance that
the first atom bomb would set the atmosphere afire;
you wouldn't want to have to say, well, I didn't
think to check that...

    Every kilogram of material striking the
atmosphere at 40,000 m/sec (average for a
meteoroid) generates a specific heat
(proportional to temperature) of 194,134
calories. That's 8.12256656 ? 10^12 ergs.
At 400,000 m/sec, it's 100 times greater, or
8.12256656 ? 10^14 ergs. The surface area of
ONE SIDE of the Earth is 250,000,000 m^2.
So the average energy delivered is
3,000,000 ergs per m^2 per kg, at this
velocity, or about 1/2 of a joule.

    The Sun's flux is about 1400 joules
per m^2, so to equal the heat of Sun,
the event would require 2800 kilos
PER SQUARE METER impacting the atmosphere,
or more than a ton of iron particles per
square meter. This is unlikely many light
years from a supernova. (If you were closer,
you'd have other, bigger problems!)

    Big sigh of relief... On the other hand,
this calculation raises an interesting point
for meteoritics. The impact of a really big
object (100's of meters) would involve the
atmospheric impact (first) of billions of
kilos in a few thousand square meter area.

    Obviously, one could have an air-burst
impact that could produce a flash many, many
times the strength of sunlight, 10 to 100
times greater, as great as any nuclear weapon
would produce. This makes the reports of a
flash at Tunguska 40 kilometers away that was
strong enough to char clothing more likely
to be true (not that I doubted them). It just
explains them quantitatively.

    No, the iron particles don't get through
the atmosphere and ding up mammoth tusks with
little pits! The atoms of iron DO float down
and get deposited in sediments world-wide,
though, where they can be detected. From such
a recent event, the number of 60-Fe atoms should
be much higher than the numbers found in
Knie's 2.8 million year old sediments.

    The failure to find them would not invalidate
the rest of Firestone's isotopic anomalies, just
invalidate a supernova as the source. There are
other nasty energetic events to which the Earth
could have been exposed: a nearby short-duration
Gamma Ray Burst, a concentrated flux stream of
cosmic rays magnetically confined by the magnetic
field of our galaxy, a Type I supernova of a fast
passing star, or something we have never observed
yet.

    Isotopic anomalies such as he has discovered
require an energetic event in the neighborhood in
recent times. Period. End of story. Since this
represents an undefined and unexpected danger of
high magnitude, I, for one, would like to know What
The Xxxx it was. Only prudent, as the Elder Bush
used to say...

    Just because the neighborhood has been
quiet for a few thousand years, we can't
assume it always will be.
Received on Mon 31 Oct 2005 06:34:56 PM PST