From: Jeff Davis (jdavis@socketscience.com)
Date: Wed Oct 20 1999 - 15:58:51 MDT
Robert Bradbury wrote:
>However, very *long* term solid state preservation is probably impossible
>due to the damage caused by the radioactive decay of the frozen atoms....
Then spike wrote:
> I propose we dig up coal, a form of carbon
> free of carbon 14,...
Then Robert replied:
>I believe you're approach would work. However I think that most
>of our internal radiation exposure comes from K40, not C14.
>Perhaps a little radioactive iodine,...
>the...largest dose ... from Radon...
Uh, I disagree. Let's start at the beginning.
What do you mean by preservation? If every atom has to be exactly as it
was at time t=0, then yes, preservation is impossible. If, however you're
talking about preservation for the purpose of reanimation from cryonic (or
some other form of) biostasis, then you're dealing with a particular set of
variables which will determine what *degree of preservation* will be
*adequate*. The crucial factor is usually seen as preservation of the
unique information which manifests the unique you (synaptic patterns being
the top candidate). Another school holds that a level of structural
integrity demonstrated by survivability is the proper standard.
At one extreme, where repair or reconstruction is carried out by fully
mature, almost-unimaginably-capable nanotech assisted by equally
over-the-top AI, the information is all you need. At the other extreme
where no repair is possible, you need a suspension-unsuspension procedure
which inflicts no more damage than the body itself can repair (with
assistance from some sort of future, but nevertheless semi-conventional,
medical capability). In the latter case the additional damage due to
radioactive decay could, conceivably play a role.
But here's the problem.
The seriousness of damage is a function of how many radioactive atoms there
are to decay, how much time--how long is the period of
preservation--passes, which will determine what fraction of them decay (you
know, half-lives), the various destructive potentials of the various modes
of decay (alpha, beta, gamma, spontaneous fission w/neutron emission), and
perhaps most important, what is damaged.
My impression is that these factors, separately and in combination, tend to
reduce to insignificance the consequence of damage due to radioactive decay.
First and foremost the fraction of radioactive atoms is, I suspect, too
small to matter.
Second, my guess for preservation time--the time for the development of
reanimation capabilities--is 150 years, give or take a hundred. Most, but
not all, of the half-lives are, I would wager, much longer.
Thirdly, beta decays are insignificant, and alpha and gamma emissions will
only cause a narrow linear pattern of molecular ionization along the path
of the emitted particle/photon.
And finally, in regards to what gets damaged, the scale of synaptic
structures is so much larger than the scale of radiation damage that the
crucial identity information remains unaffected (in fact you have
additional information in the form of a radioactive decay event artifact).
DNA information is too redundant to be degraded. Non-neural structure is
generic, so, in terms of information loss, unaffected.
As to damage that effects survival-related functionality, look at the
radiation doses necessary to kill a living human (my impression is muy
mucho rads), and compare that to the total dose potential contained in the
body. I don't have these numbers. How much potassium is in the body?
What fraction is radioactive? What's the half-life compared to say 500
years? The other isotopes?
And while it doesn't answer the above questions, with or without
nano-repair or improved cryosuspension techniques (or a nicely balanced
combo of the two) the issue of radiation damage is moot. With it,
radiation damage is repairable, and without it, freeze damage predominates.
------------------------------------------------------------
Spike, the zen master, wrote (approximately): "I don't care if they laugh
with me or if they laugh at me, so long as they laugh." Then he wrote,
"...coal, a form of carbon free of carbon 14,..." Then I laughed. The
monastery curriculum not to strong on the radiochemistry of coal, eh, spike?
Next you'll be telling me that carbon 14 dating means that your girlfriend
is radiant.
Best, Jeff Davis
"Everything's hard till you know how to do it."
Ray Charles
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