The Cosmic Microwave Background Radiation (CMB) is thermal radiation in the radio spectrum filling the observable universe with an almost uniform glow at 2.75 K as a relic of Big Bang.
Is CMB a form of Downwelling Longwave Radiation (DLR) to be added to the incoming radiation from the Sun in an energy budget for the Earth with atmosphere?
CO2 alarmists believing in a False Stefan-Boltzmann Law (False-SB) with two-way radiative transfer of heat energy between bodies of different temperature, would say Yes: CMB is a form of DLR which heats the Earth. The weak glow at 2.75 K is heating the globe.
Scientists using a True-SB, with only one-way transfer from hot to cold, would say No: There is only transfer of heat from the Earth to the cosmic background at 2.75 K.
What do you say? Yes or No? Is the colored picture of CMB a proof that CMB heats the Earth?
Inlägg
Wow, this raises an interesting question.
SvaraRaderaHow did they ever manage to pick up signals from the CMB in the sixties in the first plays being situated down on earths, at least 270K warmer, surface?
A bit of topic but your posts could be a lot easier to read if you looked into this
SvaraRaderahttp://watchmath.com/vlog/?p=438
and executed whats there...
How does the Earth know not to absorb the energy reaching it from the CMB? What does it do, reflect those photons?
SvaraRaderaRadiowave photons?
SvaraRaderaThanks for the Latex hint.
SvaraRaderaYes, acc to the formula: R = sigma (T^4 - T_b^4)
SvaraRaderaR will be less than with T_b=0.
Why not answer the question? How does the Earth know not to absorb the energy reaching it from the CMB?
SvaraRadera"How does the Earth know not to absorb the energy reaching it from the CMB?"
SvaraRaderaHow do molecules know not to transport (heat)energy from the cold to the hot wall?
To Lasse H: if you stand naked on the South Pole at - 50 C, would you say that
SvaraRaderayour body is being heated, because at - 60 C the heating would be smaller?
To Anonym: Did Planck say that there is a flow of energy from deep space
at 3 K to the Earth? If not Planck, then who?
Yes Claes, I will freese less at -50 than at -60. For the earth: It will radiate less at higher background temp, acc to the formula above. With constant input energy from sun the earth temp will rise compared to the case with a colder background. Right or wrong? (I am just talking about the radiation, no termodynamics is involved)
SvaraRaderaHow does it "know?"
SvaraRaderaClearly vibrating molecules react differently to lights of different intensity and frequency. Cause and effect have been established experimentally, and it has always been the experience that colder backgrounds cannot raise the temperature of a warmer body.
Photons (apologies if you model it as waves) only exist in the space between matter. When they are "absorbed" they are either converted to increased kinetic energy of the molecule, or reemitted. The molecule, of course, is already vibrating, and emitting as a result. Only under certain conditions can there be conversion.
Since temperature is mechanical motion, I like to use a mechanical analogy, a tandem bicycle. This speaks only to intensity, not frequency. You are the sun, on the front, pedaling furiously. On the back is a crash-test dummy, the earth's surface, with its feet taped to the pedals. The "hotter" the sun's pedaling, the "hotter" the earth. Now put a third seat on, with a child pedaling lightly, the CMB. The child's pedaling will just keep up with the chain, but it does not possess the potential to "heat up" the crash test dummy. Even when the sun sets, the stored mechanical energy in the crash test dummy (say it has an internal flywheel) will keep it oblivious to the child until it becomes "colder" than the child. Not a perfect analogy, I know.
"it has always been the experience that colder backgrounds cannot raise the temperature of a warmer body."
SvaraRaderaHa ha, well I guess these clothes that I am wearing can't be making me warmer then. What a fool I must be for imagining that they were!
Your analogy is risible and does not explain why the Earth would somehow absorb a 100 micron photon emitted by the sun, but not one emitted by the CMB. Try again - explain to me how, when two photons of the same wavelength fall upon it, the Earth knows to absorb the one from the Sun and not the one from the CMB.
What is a radiowave photon? Has anybody observed anything like that?
SvaraRadera"these clothes I'm wearing can't be making me warmer"
SvaraRaderaClothing works because it inhibits convection. Write the the 1st Law energy balance equation for a thin layer on the surface of your skin. With heat input constant on the left side (from your body),if convected heat is suppressed on the right side, surface temperature will rise, but obviously not beyond body temperature. Surface radiation simply follows temperature. The same was demonstrated experimentally for greenhouses by R.W. Wood. They work because the walls are solid, the door is closed, not because they somehow can violate the 2nd Law through "radiative forcing." Gas is not glass - it cannot inhibit convection.
"Your analogy ... does not explain why the Earth would somehow absorb a 100 micron photon emitted by the sun, but not... by the CMB"
There is more to light than wavelength. Photons come in streams of different temporal and spacial densities. If the surface molecules are already vibrating and emitting madly, a weak stream from any source cannot make them go faster.
"Radiative forcing" requires a heat input term in the 1st Law equation from a colder atmosphere which simply cannot be there, by the experimental observation of the 2nd Law.
Another inane comment, Claes, which answers no questions, furthers no conversation, and merely serves to be irritating. Are you having fun?
SvaraRadera"Gas is not glass - it cannot inhibit convection"
SvaraRaderaIs convection the only means of heat transport? Is there another one you can think of, that begins with R, maybe? And do you know what effect carbon dioxide in the Earth's atmosphere has on that kind of energy transport?
"If the surface molecules are already vibrating and emitting madly, a weak stream from any source cannot make them go faster."
"Madly" is an absurdly imprecise term but in fact, the Earth is quite capable of absorbing a 100 micron photon, no matter what its origin.