[meteorite-list] Meteorites and Neutron releases inhyper-velocity impacts

From: Sterling K. Webb <sterling_k_webb_at_meteoritecentral.com>
Date: Sun, 23 Dec 2007 13:03:06 -0600
Message-ID: <02a801c84596$74769ac0$b64fe146_at_ATARIENGINE>

Hi, EP, List,

    Fossil fuels are depleted in Carbon 14 for a very
simple reason: once a living being becomes a fossil, and
eventually a fuel (coal, gas, oil), it has been sequestered
away and has not exchanged any carbon with the rest
of the universe for millions of years. Hence, all the C14
has decayed away (half-life < 6000 years); it's outta there!

    I exaggerated. Life wants to eat C12, but inevitably,
some C13 and C14 will sneak in! But the C12/C13
ratio of even fossil life will be higher than inorganic
carbon taken from the environment by non-living
processes. This will spot the oldest remains of life:
http://findarticles.com/p/articles/mi_m1511/is_n4_v18/ai_19227819
    "Because living organisms concentrate the lighter
isotope [C12] in their tissues, life's distinctive signature
is usually detectable in sedimentary rocks enriched with
carbon 12."

    There were critters (OK, microbial life) in the oldest
sedimentary rock in Greenland (Akilia Island) that date
to 3.85 billion years ago. (The quote's from an article
in Discover, April, 1997; too lazy to find original academic
references... It's Sunday.)

    So, yes, life absorbs some C14... but it doesn't want to!

    How about more quote? "The rock the researchers studied
contained cell-size grains of a mineral called apatite, a
component of all organisms. They suspected the apatite
might be a marker of ancient life, so they sliced open about
50 grains and looked at them under an electron microscope.
The grains, the researchers found, turned out to have carbon
cores. To determine the carbon's source, the researchers made
use of an ion microprobe... They found that each grain
contained on average 3 percent more carbon 12 than an
inorganic origin would allow. "There is no known inorganic
process on Earth that can mimic this isotopic signature..."

    The quick among us will be saying, "Wait a minute! Isn't
there apatite in the Martian meteorites? Couldn't we...?
http://www.lpi.usra.edu/meetings/lpsc2003/pdf/1987.pdf

    The answer is "yes," but we have no baseline on Martian
rocks (no geologists on planet), so while we have the figures,
we don't know what they mean. We waiting for the foundation
of the "Geological Survey of Mars."

    And then, of course, we'll know... Just wait a century;
you'll see.


Sterling K. Webb
--------------------------------------------------------------------------
----- Original Message -----
From: "E.P. Grondine" <epgrondine at yahoo.com>
To: <meteorite-list at meteoritecentral.com>
Sent: Sunday, December 23, 2007 11:27 AM
Subject: Re: [meteorite-list] Meteorites and Neutron releases
inhyper-velocity impacts


Hi, Sterling, All,

Continuing work on the theory of everything...

>...
>Solar activity affects the Earth's magnetic
>shielding and that affects the degree that cosmic
>rays can only penetrate the atmosphere, so the rate
>of neutrons penetrating down deep into the atmosphere
>is controlled by the solar winds control of the
>magnetosphere's control of cosmic rays.

>By the time the neutrons get deep into the
atmosphere,
>they've slowed down and are not making C14 anymore.
>No, instead they're regulating the rate of cloud
>production, which is the chief mechanism for the
>regulation of the Earth's temperature, so basically
>Global Warming is controlled by Extragalactic Black
>Holes and other sources of energetic particles
>countless millions of light years away.

Another explanation offered for the relationship
between the Sun's variability and climate is simple
control of the UV flux by ozone. Unfortunately, we
don't know the exact mechanism yet. I wish we did.

> Living things are picky eaters. They do not like
>carbon atoms in all the different flavors they come
in >and spit them out -- Pwah! -- and eat only C12.

No, other way around. They eat C14, and when they die
they stop eating C14. What C14 they have in their
bodies begins to decay - decay is measured, and that's
C14 dating. (I see that dealing with Jason's dribble
has worn you out, Sterling.)

> So, the excursions in the Carbon 14 levels that have
> been associated with impacts PROBABLY comes from
> disruptions in the Earth's upper and outer
atmosphere > and its magnetic field which allow a
greater flux of >cosmic rays to penetrate.

I can't see how impact would affect the Earth's
magnetic field. Perhaps impact does affect the Earth's
atmospheric shielding.

What's bizarre here, (aside from having two 5 year
olds with potty mouth interrupting the conversation,
and perhaps Jason would like to use his freshman
physics to provide us all with his insights into this
problem), is that Firestone noticed the C14 increases,
and concluded that nearby supernova were the mechanism
of injection for impactors.

> Secondarily, the amount of C14 in cosmic debris,
>meteoritic dust, interplanetary dust, cometary dust,
>supernova dust is much higher than the terrestrial
>levels of C14, so increases in the amount of any one
>of these things that fall into the atmosphere
>would also have an affect on terrestrial C14 levels.
>The bigger the infall, of course, the bigger the
>affect.

Of course, C14 would dominate in carbonaceous
chondrites, so you would have more cometary impactors.


BUT we see the C14 levels rising with Canyon Diablo
(iron, little or no carbon?) and the Mammoth Pepperer
(iron, little or no carbon?, crater or larger pieces
still to be found.)

> Any sudden increase in radiation from beyond the
> Earth (a Type II supernova 200 light years away or
> closer) would be very noticeable in the record even
> though we might not be able to identify it as such.
> The passage through the solar system of an
> interstellar cloud of debris from such an event
> would be even more noticeable and even harder to
> identify.

a la Firestone -

>There was a small rise in the carbon-14 level
>following 1908, to be sure, but it was matched by
>other erratic ups and downs over the years and could
>have been a random jump.

>Libby calculated the force of the blast at Tunguska
>and the radiation that would have been released had
>the blast involved thermonuclear reactions. He
>concluded that the low levels of carbon-14 he found,
>even if completely attributable to the blast, could
>still only count for no more than fifteen percent of
>the whole force of the detonation. Other carbon-14
>tests in Norway, meanwhile, showed absolutely no rise
>at all following 1908, so these tree-ring experiments
>are strong evidence that the Tunguska Event did not
>involve significant nuclear reactions, if any."

>Of direct product of neutrons by an impact... if it
>occurs, the amount is small.

NO. THE CORRELATION OF 14C WITH LARGE IMPACTS IS NOW
SHOWN BY THE DATA. (all 3 datapoints - note the small
type used here.)

The problem is figuring out a mechanism that releases
the neutrons.

> In theory, even lightning can produce a
>tiny amount of C14 (high energy electrons knock a
>neutronloose which hits a nitrogen atom, etc.), but
the key word is "tiny." And since a big impact's
plasma >can produce x-rays, other energetic photons,
and lots >of bouncy electrons, some C14 will be
produced in the >air around the impact, more than
lightning could >produce, but I doubt anybody has
calculated
>the amount (if possible) and I sure not going to try.

We can estimate the number of neutrons by looking at
the 14C produced. (That is, we could estimate this if
"we' hadn't had a stroke. Elton, Doug, anyone else
here want to take a crack at this problem?) If we can
find the crater(s) (or the remains, in the case of ice
impact), as has been done at Barringer, then we know
the impactor type and size. That would limit the
problem of identifying the neutron release mechanism.

> However, material from the impactor, depending
> entirely on the carbon content of the impactor
(comet >or some other carbonaceous body), could be
distributed >as debris from the impact (or especially
in an >airburst). This could greatly enrich the local
stock >of C14 in the area of the impact. This C14
enrichment >might well be, not worldwide, but
continental or
>even be restricted to a smaller area. Carbon in a
>meteoric body would be greatly enriched in C14 as its
>exposure to energetic radiation would be greater and
>longer than terrestrial carbon.

Our data set right now is 2 irons and 1 comet.

>So, ya see, it ain't so simple...

Yes, it sure isn't.

>And you guys are simplifying way too much, in the
urge >to bash each other.

I'll differ with you in your assessment of Jason.

What does all this have to do with METEORITES, as
promised in the subject line,?

Another important consequence here is that isotopes
are used extensively in studying meteorites, so IF
impacts are releasing neutrons, particularly impacts
between parent bodies, then a whole lot of formation
timing is going to have to be looked at again.

In other words, every isotopic clock would (will) have
to be re-checked.

>Sterling K. Webb

good hunting, all
E.P. Grondine
Man and Impact in the Americas
Received on Sun 23 Dec 2007 02:03:06 PM PST