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More options Apr 1 2012, 4:13 pm
Newsgroups: alt.religion.kibology
Date: Sun, 01 Apr 2012 21:13:37 +0100
Local: Sun, Apr 1 2012 4:13 pm
Subject: Re: another weird physics question
On 2012-04-01, David DeLaney wrote:

> J. Waldby <wichitajayha...@REMOVETHISmsn.com> wrote:
>>> Following the one about the idea that forces are proportional to
>>> 1/(r^2) because there are 3 spatial dimensions: is there any similar
>>> explanation for why radiation from one body is proportional to T^4?

>>Can you bring me up to speed?  What is T here?  Also, are we talking
>>about a cubic body or a spherical body?

> T is the temperature, though technically you get that it's the difference
> in temperature between the body doing the radiating and the background it's

Isn't gross transfer Q from body 1 to body 2 proportional to (T_1)^4,
so *net* transfer from body 1 to body is proportional to

(T_1)^4 - (T_2)^4

where T is absolute temperature?  (Let's be honest: I'm trying to
remember this from about 20 years ago.)

> This is, in part, why it's so much more dangerous to be
> out in zero-degree weather than in 30-degree weather (Fahrenheit, fondly),
> and so much more dangerous again to be out in -30 -degree weather; if you
> double the temperature difference, heat loss by radiation goes up by a factor
> of 16. (Of course for weather, convection & conduction also play large parts.)

I thought convection was the most important form of heat transfer from
the human body in a cold environment.

--
"Gonzo, is that the contract from the devil?"
"No, Kermit, it's worse than that. This is the bill from special
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