X-Message-Number: 25570
Date: Mon, 17 Jan 2005 09:00:56 -0500
From: Keith Henson <>
Subject: Re: The Limpinwood X-Prize and Background Radiation

At 10:00 AM 17/01/05 +0000, Peter Merel wrote:

snip

>The pair of butterflies took off again and did another series of
>arabesques, loops, twists, and flings. Then they landed right back
>where they were before. The exact same grass blades. And this in a
>stiff breeze after a thunderstorm.

snip

See the article about Hans Moravec in the January issue of Scientific 
American.  The problem is making sense of the visual field.  Hans has been 
working on this problem for a long time.  As computers reached the 
processing power of a guppy it became possible.  He has done it and is in 
the process of making it commercial.

>  Michael Jennings <michael wrote:

>Does anyone have some figures on the effects of background radiation (0.05 
>microSievert/hr at sea level) - along with an assorted echelon of other 
>particles, such as cosmic rays and neutrons) causing damage inside 
>cryogenically frozen materials?

Yes.  Damage accumulates slowly, but is not considered a problem inside of 
at least 1000 years.   There is direct evidence in that cells have been 
frozen and revived after more than 50 years now.

>I've seen people here state that all aging and chemical reactions stop in 
>LHe and LN2  - this is of course not true ...

No, but it is a good approximation for liquid nitrogen and biological type 
reactions.  The amount of slowing at various temperatures can be calculated 
by the Arrhenius equation.  Hugh Hixon did that in this article which also 
covers why the Arctic is not cold enough.

http://www.alcor.org/Library/html/HowColdIsColdEnough.html

Keith Henson

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