Not All Radiation Causes Heat
Not all radiation will de facto add energy to any matter it comes across. It is a widespread misconception that also underlies the wrong idea about earth’s atmosphere sending heat to the surface via the re-radiation of energy off molecules such as water vapor and carbon dioxide and making the surface warmer than it was in the first place.
Any radiation of whatever frequency will only interact with a substance it comes across if that substance is of a lower energy level and has the molecular structure to accept that radiation, either by absorption or excitation.
A good example is the microwave oven many of us have in the kitchen. A microwave oven also uses radio waves but at a specific frequency that agitates water molecules – the water molecules do not absorb that radiation though, they are rocked back and forth by the undulating waves. As these water molecules get increasingly agitated and vibrate at the atomic level they generate heat. This heat is what actually cooks the food.
Of note here is that the interior of the oven does not heat up, neither the air nor the plate that revolves within the oven space, nor the plate or dish that the food is placed on, provided of course that such containers are “microwave oven safe” – meaning that they do not interact with the energy waves whirling around the oven’s interior.
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Alan Thorpe
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But what we need to know is how this applies in the atmosphere.
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John Harrison
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” re-radiation of energy off molecules such as water vapor and carbon dioxide and making the surface warmer than it was in the first place.”
Is this deliberate misinterpretation? Only then can you “disprove” it. Some of the back radiation is absorbed and thus will be thermalised but you must surely know that this does not “make the Earth’s surface warmer than it was before” I think you must know that this is not what is being hypothesised. Similarly the odd and irrelevant analogy concerning the microwave. If microwaves are not absorbed by metal etc. then of course they will not be thermalised. What was the point you were trying to make? A Grey Body surface such as that of the Earth will absorb radiation of virtually any wavelength because of the (virtually) infinite number of molecules of different substances at a correspondingly infinite number of energy states. Remember, the temperature of the atmosphere and the Earth’s surfaces are only Averages which is why IR can be emitted and absorbed in both directions. It is the net energy flow and average temperatures which are all important in using Stefan-Boltzman, 2nd Law of thermodynamics, etc. and I suspect you know this. You must also be aware that single molecule interactions may bear little or no relation to such massive and complex systems. Deliberate misinterpretation to me seems unethical and certainly of no value in the conduct of science.
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Gary Ashe
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John no matter how many times you handwave this nonsense it will not stick.
Lwir emitted from the Atmosphere has a blackbody thermalising potential of -80C
There is nowhere night or day that back welling LWIR spectra are thermalised on the Earths solid surface, 74% of the Earth is water, LWIR cannot penetrate water, there is experimental lab data to show it can aid phase change on the waters surface film, but no real world data,
You say this over and over without a slightest proof and any high school physic’s text book proves you wrong.
””’Remember, the temperature of the atmosphere and the Earth’s surfaces are only Averages which is why IR can be emitted and absorbed in both directions. ”””
You bring all these mass reactions etc whilst claiming one molecule and one photons interaction is meaningless, when it everything, as every photon ever emitted to mass, has acted and will act the same way for ever.
Why do you stubbornly ignore the photons charge.
That is what makes the photon positive or negative to the orbiting atoms of the molecules in mass.
And whether it is absorbed into the Eletrons or deflected/scattered.
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Mike
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Sorry Gary but you are the one handwaving and writing nonsense. Try looking up the charge of a photon in a high school physics text book. Send me the reference when you have found one. (You won’t).
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