[ExI] The Moon's Cold Embrace

[spike at rainier66.com]

-----Original Message-----
From: Anton Sherwood <bronto at pobox.com> 
Subject: Re: [ExI] The Moon's Cold Embrace

On 2020-8-11 15:52, spike jones via extropy-chat wrote:
> Radiating into cold space feels more like the right answer on the moon.  
> We would need to shadow the radiator with something, [....]

>...I hope you mean put it on the shady side of a mountain.  If you mean by putting up an awning, that would heat up and reradiate, heating up the radiator some ... I don't know how to do the math.  I suspect the best thing is to make the radiator swivel to present its edge to the sun (as some animals do, or so I gather).


A double swivel to go edge-on with the sun would work probably, but better would be a natural shield of stone, such as at the mouth of a lava tube, with a parabolic reflector pointing toward cold space.

The shady side of a mountain would only be shady part time.  Inside a crater would be shady always if you happened to set up at one of the poles.  Either way, you need a completely unobstructed view of cold space.  Then you can get a first order estimate of the heat-rejection capacity by estimating the temperature of your radiator and using Stafn-Boltzmann's law.  That would be the ideal case but I don't think you would miss by that much by treating cold space as 3 Kelvin

spike



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*\\*  Anton Sherwood  *\\*  www.bendwavy.org