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When someone comes in from the cold to a heated room, it sometimes feels like there is coldness radiating away from that person. Is there a sense in which we can say that coldness radiates similarly to heat radiation? Does it make sense to have a theory of thermodynamics of coldness in which heat is replaced with coldness (-heat)?

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  • $\begingroup$ Added to favorites :) $\endgroup$
    – mick
    Jan 20, 2013 at 22:26

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The coldness "radiating away" from that person is actually the "heat shadow" that person casts when standing between you and the warm wall. It's equivalent to the darkness you see from him standing between you and a bright wall, which you also wouldn't interpret as "darkness radiating away from him".

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Maybe you should look at Kirchhoff's law. What you refer to as "coldness radiation" is actually heat radiation (flow) away from you. What you experience as heat radiation is heat radiation into the opposite direction, i.e. from a warm body to you.

Depending on their temperature (and surface), all bodies emit heat radiation. The net heat flow (by radiation) between two bodies is the difference between the two flows.

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