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Politics : The Environmentalist Thread -- Ignore unavailable to you. Want to Upgrade?

To: HPilot who wrote (22138)	7/11/2008 2:20:26 PM
From: neolib	Respond to of 36921

It would be some of both. A cloud is not transparent in IR. But no matter what he might have thought he was measuring, you can place a sample of any material in a suitable tube, and with the the sample at uniform temp, you can measure the IR coming from it, and assign an emissivity to the material. The phase of material is not going to prevent you from doing so, as the example of the sun points out. In the case of a gas, the emissivity is going to be a function sample depth, i.e. how long a tube you are looking at. In the case of most solid materials, the emissivity is a function of the optical color, to a good approximation.