## tisdag 8 mars 2011

### Where is the Beef of the 2nd Law of Radiation?

In my upcoming book Mathematical Physics of Blackbody Radiation and in Computational Blackbody Radiation from Slaying the Sky Dragon, I derive a Stefan-Boltzmann Law expressing the momentary radiative heat transfer Q12 to a blackbody 1 of temperture T1 from a blackbody 2 of higher temperature T2 of the form
• Q12 = sigma (T2^4 - T1^4), where T2 is bigger than T1.
This can be viewed as a 2nd Law of Radiation expressing heat transfer from warm to cold.

In the literature, this law is found in the form
• Q12 = sigma T2^4 - sigma T1^4,
supposedly being obtained from Stefan-Boltzmann's Law for one blackbody of temperature T radiating into a surrounding at 0 K, of the form
• Q = sigma T^4
by an ad hoc combination viewing
• sigma T2^4 to be the heat transferred from 2 to 1 (as if T1 = 0)
• sigma T1^4 the heat transfered from 1 to 2 (as if T2=0).
But a proof that this ad hoc combination reflects physics is missing, and even worse it has led to a misinterpretation of Stefan-Boltzmann's Law as expressing "backradiation" as heat transferred from a cold to warm body (transfer from 1 to 2 even if T1 is smaller than T2).

This misinterpretation of Stefan-Boltzmann's Law underlies global warming alarmism with atmospheric greenhouse gases capable of warming an Earth surface, which is warmer than the atmosphere.

My new derivation of Stefan-Boltzmann's Law gives no support to the ad hoc version
with "backradiation" from cold to warm.

This leads to the requirement that all those who use "backradiation" as the basis of their climate alarmism rooted in many institutions around the world, as well as many misled skeptics, come up with a proof of their Stefan-Boltzmann Law harboring the phenomenon of "backradiation". The question to all these thousands of scientists is:
• Where is the beef? Where is the proof of their version of SB with "backradiation"?
Scientific laws require rational theoretical motivation (and experimental testing) and cannot
be allowed to be invented ad hoc, e.g. by some ad hoc algebraic manipulation without physical significance, as in the freely invented version of SB with "backradiation" without justification.

What is required is a proof of a 2nd Law of Radiation. I have given one proof without "backradiation". Those who speak about "backradiation" are asked to justify their usage of this term. Without justification it has no place in science.

As a defense, it is commonly said that the 2nd Law is a law of physics which can neither be understood nor proved, but yet is one of the basic laws of physics which can only be true
and as such cannot be questioned. But this respresents a degeneration of the most important
principle Descarte's scientific rationality of not believing in anything unless there is a good reason to do so. To uncritically worship a 2nd Law without motivation is not science, only mysticism. Proofs can be given and proofs must be given. So where is the beef? Hot or cold?

The following counter-argument will certainly be posed: Algebraically there is no difference between (1) Q12 = sigma (T2^4 - T1^4) and (2) Q12 = sigma T2^4 - sigma T1^4, and so what difference can it make in physical reality?

Yes, there is a difference in reality, because in (2) Q12 results from cancellation of transfers in opposing directions, while in (1) Q12 is directly given as a net transfer from warm to cold. The difference between (1) and (2) is most pronounced if T1 = T2 with a zero net flow in (1), while zero net flow in (2) requires exact cancellation of gross quantities, which is an unstable process in the sense that small variations in the gross transfers may alter the net flow considerably.

But an unstable system cannot persist over time which means that (2) cannot be expected to reflect physical reality, and a justification is also lacking. In other words: "Backradiation" is
a fictitious invented phenomenon resulting from an ad hoc algebraically invented radiation law without physical reality and without any justification.

#### 26 kommentarer:

1. Som jag har förstått det får man den konventionella Q12 = sigma T2^4 - sigma T1^4 genom resonemanget att hur mycket en kropp strålar är oberoende av vad som sedan händer med strålningen/var den absorberas, och det tycker jag låter ganska rimligt.
Är det detta argument du vänder dig emot, och vad är i så fall fel/mystiskt med det?

2. T1> T2 or T1>> T2 should mean different rate of cooling of T1 at the same starting temperature of T1 if there is backward radiation, and if convection can be avoided during the trial. (?)
T2 has a temp. and beams energy in all directions. What happens to the energy that goes in the direction of the T1?
Interference (?)

3. Ja, jag anser att detta är ett ad hoc påhitt utan fysikalisk grund. Det krävs en positiv motivering att det så skulle vara fallet, och bara ett allmänt att det skulle kunna vara så. Som i ett brottmål fordras konkreta bevis, inte bara löst tyckande. Eller vad tycker Du?

4. Då förstår jag. Tack.

Jag har en känsla av att påståendet att det en kropp strålar är oberoende av vad som händer med strålningen kan motiveras genom att information inte kan färdas snabbare än ljusets hastighet i vakuum (eftersom det skulle bryta mot vår uppfattning om kausalitet, att orsak kommer före verkan). Ponera att jag har en platta som avger värmestrålning. Ett ljusår bort sitter en annan person med en platta som tar upp en liten del av den strålning min platta skickar ut. Om strålningen från min platta är beroende av tillståndet hos den andra personens platta, gör inte det då att min plattas strålning ger omedelbar information om någonting som finns ett ljusår bort? Är inte det ett problem?

5. För att något skall kunna emitteras så fordras att det finns någon form av receptor till det emitterade. Att emission ut i tomma rymden är möjlig är en hypotes som fordrar konkret belägg för att vara trovärdig. Det räcker inte med att säga att det vore konstigt annars.

6. Claes, acc to your view on the two body SB, there is no radiation of energy (IR) inside a metal sphere with equally warm inner surface.

7. @ Lasse H

I think your example actually supports Claes' view. Radiation within a metal sphere must exist in the form of standing waves, with nodes on the boundary, i.e., the inner surface. Mathematically, these can be constructed out of two equal waveforms travelling in opposite directions, but the physical reality is that no energy is transferred from one point on the boundary to another. The energy is 'held in place' in the space inside the sphere (it can be made to do work via a thermocouple, for example). Inductively, one can argue that the enrgy assocaited with the radiation of a cooler object near a hotter one is also held in place by an equal amount of energy from the hotter object, while the remainder of the energy from the hotter object is transferred by travelling waves to the cooler one.

8. Claes,
In terms of engineering experience there are two problems with your explanations.
1/ lack of consideration of absorptivity and emissivity. While Kirchoff's law states that emissivity and absorptivity of a surface are the same in surroundings at its own temperature, the absorptivity of a receiver surface is related to the temperature of a source and the emissivity is related to the temperature of the reciever.
For example a polished metal surface (a mirror) will have a very low absorptivity in the visible light wavelengths but can have a higher emissivity in the infra-red temperature range (but this has no effect on a source like the sun)
CO2 gas has zero absorptivity/emissivity at a wavelength around 10 micron. So regardless of the temperatures there will always be less than blackbody radiant heat transfer between a source and CO2 gas.
2/ Lack of consideration of areas of source and receiver and their relation to each other for which engineers use view factors.

However, it is very clear that few (and these are mainly engineers)understand heat transfer including radiant heat transfer. Claes' explanation about the lack of so-called back radiation is welcome but it should make no difference to determinations of insignificant radiant heat absorbed by CO2 in the atmosphere from the earth's surface.
Read the following http://climategate.nl/wp-content/uploads/2011/02/CO2_and_climate_v7.pdf based on actual measurements which confirms calculations using the Hottel equation.

Lasse H's thought bubble above has no relevance.

keep strong
cementafriend

9. My model is simple and conceptual to exhibt essential physics, but it
can be expanded to include the effects of frequency and geometry you suggest, as I hope to show in upcoming work.

10. "För att något skall kunna emitteras så fordras att det finns någon form av receptor till det emitterade."
Borde gå att belägga eller avfärda experimentellt.

11. Claes, any concept in science is nonsense if it has no practical meaaning. It is necessary describe exactly the boundaries of use and then verify the concept within the boundaries by actual measurements. That is what engineers do. People who take a concept, part law or hypothesis out of context such as pseudo climate scientists with the black-body Stefan-Boltzman law demonstrate their lack of understanding of science and technology. Engineers have a long experience with measurements in furnaces and heat exchangers. Note Dr Noor Van Andel (the author of my reference above)is an engineer who has developed and patented an improved heat exchanger for heat pump applications see physics here http://www.xs4all.nl/~fiwihex/english/physics.html
keep well cementafriend

12. What concept is supposed to be nonsense? Anything I said?

13. Claes: Is there any experiment in which your theory and the conventional one predict different results? Would such an experiment be possible to carry out?

14. Yes, of course there are many possible experiments showing that the theories are different and predict different things.

15. Claes, am I right in thinking that you don´t deny backradiation, from e.g. CO2, but you deny that this radiation is absorbed by the earth for some reason?

16. No, I don't accept backradiation as heat transfer from cold to warm.

17. "Claes Johnson sa...

What concept is supposed to be nonsense? Anything I said?"

No, nothing you have said recently. You are putting together various knowledge of thermodynamics and heat transfer to explain actual findings and measurements and that is useful.
Sometime ago, you highlighted the blackbody theory dQ= 4dT which may (repeat may) only be correct for an isolated infinite black body surface radiating in a vacuum. It has no relevance to the radiation absorption or emission of CO2 in the earths atmosphere. CO2 is a trace gas in the atmosphere not a surface and it is not a black body. CO2 only absorbs radiant energy in very narrow wavelengths.
Any article about a theory or experiment which does not expain in detail the assumptions, measurement coditions (if any), the boundary limitations and the possible errors is not worth considering (even if they are peer reviewed). My comment basically refers to the junk science which is produced by supporters of AGW. They assume the science (about which they have no understanding) is settled and then quote meaningless model results often not even saying the results are from a doubtful model.
keep well- cementafriend

18. "Yes, of course there are many possible experiments showing that the theories are different and predict different things. "

Could you please give us some examples?

19. Radiative heat transfer in different geometrical configurations which can be modeled by wave equations with radiation, but which cannot be modeled by SB.

20. claes i do not understand how you can say that the hypothesis that a source emission will not depend on the environment should be a stronger hypothesis than the opposite. anyhow, this bold statement triggered me to do an experiment that i believe could be interesting to your research in what you call backradiation.

i did the following experiment:
i took two old style bulb lamps (one 60W and one 120W) i put them in front of one other and switched them on. i looked at the 60W lamp via a pinhole collimator. there was no change in the intensity of the light emitted by the lamp when i looked at it from different angles.
i then tried the following. i took two lamps marked 60W and put them in front of each other in a dark room. i sat in an armchair in the middle point between them with a book open in front of my eyes. i then switched one on and noted on my research log book that i could read my book. i switched the first lamp off and switched the second one on and noted in my research log book that i could read my book. i then, full of expectations, switched both lamps on at the same time. to my enormous surprise i could read my book! and i dare to say that the light intensity was double as much as in the first two cases. i noted this on my log book as well. i even wrote that, for obvious reasons i could not perform a double blind study.

21. Lorenzo: I present a wave model where the heating of one body (1) by radiation from another body (2), depends on the temperatures of the bodies with heating only if the temp of 2 is bigger than of 1. This effect is not an assumption but a consequence of the wave model assumptions.

22. you wrote:
"För att något skall kunna emitteras så fordras att det finns någon form av receptor till det emitterade. Att emission ut i tomma rymden är möjlig är en hypotes som fordrar konkret belägg för att vara trovärdig. Det räcker inte med att säga att det vore konstigt annars."

and to the question:
"Som jag har förstått det får man den konventionella Q12 = sigma T2^4 - sigma T1^4 genom resonemanget att hur mycket en kropp strålar är oberoende av vad som sedan händer med strålningen/var den absorberas, och det tycker jag låter ganska rimligt.
Är det detta argument du vänder dig emot, och vad är i så fall fel/mystiskt med det?"

"Ja, jag anser att detta är ett ad hoc påhitt utan fysikalisk grund. Det krävs en positiv motivering att det så skulle vara fallet, och bara ett allmänt att det skulle kunna vara så. Som i ett brottmål fordras konkreta bevis, inte bara löst tyckande. Eller vad tycker Du?"

my experiment proves that emission is not depending on absorption by other objects.

23. You have to make a distinction between outgoing radiation (waves) and the heat transferred by the waves. Stefan Boltzmann's basic law concerns heat transferred when radiating into an exterior at 0 K. The temp of the exterior influences how much heat is transferred from the body.

24. ok, you mean that the sentence:
"Ja, jag anser att detta är ett ad hoc påhitt utan fysikalisk grund. Det krävs en positiv motivering att det så skulle vara fallet, och bara ett allmänt att det skulle kunna vara så. Som i ett brottmål fordras konkreta bevis, inte bara löst tyckande. Eller vad tycker Du?"