<hal@finney.org> On February 22, 2000 Wrote:
>I think it is likely that most injuries, including trauma, ischemic and freezing
>injury, will involve some loss of information.
I'll only talk about freezing in this post and I'll grant you things would be hopeless
if the freezing process brought on turbulence. That would mean that tiny changes
in initial conditions would lead to huge changes in the outcome, it would mean that
two points arbitrarily close together before the freezing could be far apart after,
it would mean loss of information making recovery impossible.This probably
doesn't happen so things are not completely hopeless, only almost hopeless.
Chaotic turbulent flow sets in when a system has a Reynolds number that is
larger than about 2000, although you might get some non chaotic vortices if it
is bigger than 30. We can find the approximate Reynolds number by using the
formula RDV/N. R is the characteristic size of the volume we're interested in,
we're interested in cells so R is about 10^-6 meter. D is the density of water
10^3 kilograms/cubic meter. V is the velocity of the flow, during freezing it's
probably less than 10^-3 meters per second but let's be conservative, I'll give
you 3 orders of magnitude and call V 1 meter per second. N is the viscosity of
water, at room temperature N is 0.001 newton-second/meter^2, it would be less
than that when thing get cold and even less when water is mixed with glycerol
as it is in cryonics but let's be conservative again and ignore those factors.
If you plug these numbers into the formula you get a Reynolds number of about 1.
1 is a lot less than 2000 so it looks like any mixing caused by freezing
would probably be laminar not turbulent.
John K Clark jonkc@att.net
>
> The unanswered question is whether this information loss is sufficient
> to obliterate personality, memory, and other important brain state.
> I don't think we know enough at this time to give any sort of definitive
> answer to this question.
>
> This was my objection to the Ralph Merkle essay mentioned a couple of
> weeks ago; I thought he was excessively optimistic in claiming that the
> answer was largely known. But other people who have actually looked at
> frozen brains, including Eugene and cryonics "godfather" Mike Darwin,
> seem to have a more pessimistic view.
>
> Hal
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