Understanding OLR and DLR vs Radiance Measurement by CERES and Pyrgeometer.

Outgoing Longwave Radiation OLR from the Top of the Atmosphere ToA is measured by a CERES satellite looking down on ToA equipped with a sensor as one end of a thermocouple with its other end kept at a steady temperature generating a voltage scaling with the temperature difference at its ends. 

The CERES instrument is calibrated by determining a gain factor from sensor temperature to radiance letting the instrument look at a black body of known temperature $T_B$ with assumed Planck radiation $\sigma T_B^4$ while recording the sensor temperature. With the gain factor so determined the instrument reports radiance from ToA from a reading of sensor temperature. This is the simplest form of calibration assuming linearity. Very primitive technique, where the details of the instrument do not matter. It is like measuring intensity of rainfall using your hands to collect water calibrated to a faucet. The accuracy is at best 1 W/m2 or 0.4% of the same size as estimated Earth Energy Imbalance from CO2.  

A pyrgeometer measuring Downwelling Longwave Radiation from the atmosphere to the Earth surface also uses a sensor as one end of a thermocouple with the other end kept a base temperature, and also measures a voltage scaling with temperature difference. The calibration is here different because the outgoing radiation from the sensor can no longer be included in the calibration process, but has to be supplied through a Planck formula $\epsilon\sigma T^4$ with $T$ sensor temperature and $\epsilon$ sensor emissivity. The accuracy is at best 5 W/m2 again too big to detect global warming if present.

OLR and DLR are thus measured in a similar way, but with different forms of calibration the difference being that OLR faces empty space ay 0 K, while DLR faces the Earth surface. The accuracy is not enough to decide any size of global warming, although it is claimed that trends can be detected. 

In both cases Planck's Law in the form $\sigma T^4$ is used, which in the case of DLR is incorrect because the correct form is $\sigma (T^4-T_E^4)$ with $T_E$ Earth temperature expressing negative DLR.  

Summary: Measurements of OLR and DLR are made to detect global warming. The accuracy of the instruments is not good enough to detect any warming if present. DLR measurements can be questioned since an incorrect Planck Law is used. OLR and DLR as radiance as process variable fluctuate and as such are difficult to measure.  

EEI is a cornerstone of global warming alarmism, and so measuremennt of EEI has become a prime task for instrument technology, which does not seem to have delivered. The effect of EEI on surface temperature is unknown and impossible to measure and DLR is a misconception based on an incorrect form of Planck's Law.

ChatGPT on objective of CERES: 

CERES connects to global warming because it:

• Measures the planetary energy balance directly at TOA.

• Detects changes in OLR and OSR (reflected shortwave) caused by greenhouse gases, aerosols, clouds, and ice.

• Provides the evidence that Earth is currently taking in more energy than it loses — the physical basis of global warming.

ChatGPT on objective of measuring DLR :

• Provide a direct measure of the atmosphere’s infrared emission to the surface, essential for closing the surface energy budget, quantifying the greenhouse effect, tracking climate change, and validating models.

We read that the objective of CERES is to support global warming alarmism by measuring and reporting EEI attributed to CO2. But the objective is not reached, because (i) the accuracy of the measurement is not better than 1 W/m2, which is the expected size of EEI, and (ii) attribution to CO2 to is not credible because it is swamped by changes of cloud cover. We read that the objective of measuring DLR by a pyrgeometer is to quantify greenhouse effect. Both cases amounts to "chasing after wind" using "ghost detectors". 

Is Measuring Temperature at Distance Possible and Useful?

Climate alarmism of global warming claims to be supported by measurement of the energy balance of  Earth+atmosphere by instruments like pyrgeometers, bolometers and radiometers with an accuracy of at best 1-2 Watts/m2 compared to a total of around 240 W/m2 and a projected total imbalance of 4 W/m2 as "radiative forcing" from doubling of atmospheric CO2 corresponding to a warming of 1 K. 

The case for global warming may seem weak from these measurements, but nevertheless they serve to foster alarmism. 

To properly evaluate the measurements it is necessary to understand how these instruments are designed and how they operate. For a pyrgeometer or bolometer using a thermocouple as sensor, there are two fundamentally different views:

1. A thermocouple essentially measures incoming radiance from a source as a process variable. 
2. A thermocouple essentially measures a source temperature as a state variable.  

It is natural to make a comparison in terms of a bank account:

1. Difference between deposits and withdrawals as process variable.
2. Total savings as state variable.

We understand that total savings may be fairly stable, while deposits minus withdrawals can fluctuate quite a bit. The same for temperature vs radiance imbalance. 

What does then a thermocouple as sensor in fact measure? Radiance or temperature? 

1. There is a widely spread view that a thermocouple essentially measures radiance and so can be used to reliably measure both incoming and outgoing radiance for Earth+atmosphere and so determine imbalance, even if the accuracy is not better than 1-2 Watts/m2, and so detect global warming. Radiance is then measured through a calibration process confronting the sensor with sources of known temperature $T$ with radiance according to an assumed Planck-Stefan-Boltzmann Law of the form $\sigma T^4$.  

2. There is also a different view that a thermocouple essentially measures source temperature by essentially allowing the sensor to take on the source temperature by radiative equilibrium established optically at distance. In practice the radiative equilibrium source-sensor is only partially established by sensor cooling, but the principle of radiative equilibrium with equal temperature remains. 

Case 2 builds on a clear physical principle of radiative equilibrium in stable measurement of a state variable.

Case 1 is based on instrument calibration vs sources/blackbodies of known temperature $T$ assumed to give radiance input of $\sigma T^4$, while the true input is PSB in the form $\sigma (T^4-T_i^4)$, where $T_i$ is instrument base temperature which is not 0 in general. Case 1 is thus based on a calibration process using an incorrect PSB law inflating input radiance. Moreover the measurement concerns a process variable prone to instability. There are cryogenic sensors with very small $T_i$ and better precision. A proof of the correct PSB Law in classical terms without statistics is presented here and in this talk.

Case 1 is consensus and is used to support alarmism from measured radiance imbalance of Earth+atmosphere as if this is a fact. But the measurement precision barely can capture any imbalance from doubled CO2. Unfortunately many climate skeptics embrace the idea that a pyrgeometer measures massive incoming radiance (Downwelling/Upwelling/Outgoing Longwave Radiation) and so go along with a basic alarmist argument: The measured energy imbalance is the result of more CO2. 

A careful study shows that a thermocouple in fact measures source temperature as stable output, while derived radiance can be misleading because the calibration uses an incorrect PBS Law and is prone to instability. This means that measured energy imbalance can be questioned along with alarmism.

But the discussion is pretty much closed on 1 as the truth. Hopefully a new discussion can take place around the question: What does a thermocouple primarily measure and on what physical grounds? How can a thermometer acting at distance be constructed? Is an IR-camera such a thing?

How Does a Thermocouple Work?

This is a follow up on the previous post. 

A thermocouple consisting of two rods made of different metals joined to form one rod, registers a voltage proportional to the temperature difference between its two ends as a result of the Seebeck effect creating an electric potential difference from temperature gradient. Putting one end as sensor (or measurement junction) in optical contact through a camera lens with a distant object, will make it attain the same temperature as the object as an expression of thermal equilibrium just like an ordinary thermometer in contact with an object. Keeping the other end as reference junction at a known temperature makes it possible, after calibration, to read the temperature of the object.  

The thermocouple can also be used without calibration by varying the temperature of the reference junction until the voltage is zero. 

The essence is that a thermocouple reacts to temperature as prime sensor input. 

In climate science the following different narrative is presented: The input to the sensor is not primarily temperature but radiation as number of absorbed photons emitted by the object at temperature $T$, incorrectly claimed to scale with $T^4$, see earlier post, and so to allow temperature to be determined from sensing radiation by counting incoming photons. This scheme is claimed to be realised in a pyrgeometer which when directed to the sky on its display reports Downwelling Longwave Radiation DLR emitted by the sky contributing to substantial global warming of the Earth surface. The sensor of a pyrgeometer is a thermocouple, which thus is claimed to measure primarily radiation and not temperature.

But above we made clear that a thermocouple does not measure radiation, since it has no mechanism for counting photons as carriers of radiation. What a pyrgeometer does is to measure the temperature of the sky visible by infrared light which can be 255 K at 5 km altitude. This does not feed any climate alarmism. 

Unfortunately, the view that a pyrgeometer measures radiation propagated to sell climate alarmism, seems to be shared by climate skeptics like Happer and Spencer counteracting their criticism. A typical honest instrument, like a thermometer, reports what it primarily measures, but a pyrgeometer reports something else which is used to mislead into climate alarmism.  

Planck 1900: Fall of Theoretical Physics: Greenhouse Effect

Planck describes in his autobiography his theoretical derivation of Planck's Law for black-body radiation presented in 1900, in complete agreement with observations, based on statistics of quanta, in these very disturbing terms:

• It was and act of desperation.
• I was ready to sacrifice any of my previous convictions about physics.

What Planck gave up was the rationality of classical deterministic physics for a new form of indeterministic statistical physics. A monumental sacrifice. Why? A Faustian deal? In any case the consequences have been far reaching since quanta has become the code word of modern (quantum)  physics, even if the meaning has never been made clear. 

Planck's Law integrated over all frequencies takes the form of Planck-Stefan-Boltzmann's Law:

• $R=\sigma T^4$                (PSB)

where $R$ is radiance as energy flux measured in e g W/area, $T$ is an absolute temperature and $\sigma$ a constant. (PSB) is a poster formula for modern physics of the same stature as $E=mc^2$, but if you ask a modern physicist about the real physical meaning of (PSB), you will get the following contradictory answers:

1. $R$ is the outgoing radiance of a black-body of temperature $T$ independent of the environment of the body, as a stream of emitted photons. 
2. $R$ is the outgoing radiance of a black-body of temperature $T$ into an environment of a zero absolute temperature.  If the environment has temperature $T_0<T$ then $R=\sigma (T^4 - T_0^4)$. Fundamentally different from 1.

A theoretical/pure physicist will say 1. and an applied/real physicist will say 2. But theory cannot contradict reality. The reason of the confusion between 1. and 2. is that Planck's derivation is not based on real physics but on statistics without clear physics as quanta physics.

We conclude that 1. is a misconception, but a widespread misconception, which has served as the basis of the so called GreenHouse Effect GHE underlying climate alarmism. What 1. tells the climate alarmist is that the atmosphere is sending massive so called back-radiation to the surface of the Earth, twice as big as the radiation from the Sun. The sky cloudy or clear will thus warm the Earth according to 1. which with a bit more CO2 from fossil fuels will cause global warming with terrible consequences for humanity. From 1. follows alarm, while there is no alarm from 2. 

A climate alarmist will present evidence of global warming by back-radiation from the sky from instruments like pyrgeometers or AERI/radiometers, which report massive back-radiation or Downwelling Longwave Radiation DLR on their displays. The idea is that if an instrument display shows something, it must be something real in particular if the instrument is heavy and expensive. But an applied/real scientist would ask for information about the physics of the instrument, what de facto is being measured and how and what is displayed. Right?  

Inspecting the manual of a pyrgeometer or radiometer shows that the instrument is based on 1. which thus gives the basis for what is shown on the display as massive DLR or back-radiation. With 2. the display would show a much smaller warming effect of the atmosphere. 

Climate alarmism is thus based on 1. Understanding that 1. is not real physics, reduces the main argument of climate alarmism to zero. 

A different proof of Planck's Law in terms of classical deterministic physics without statistics is presented as Computational Black Body Radiation, which shows that 2. is physics and 1. not. You find an analysis of the pyrgeometer as ghost detector of back radiation in this sequence of post. Also check out this talk on Misunderstanding Planck's Law.

PS1 In 1900 Planck was professor of theoretical physics at the University of Berlin asking for a demonstration of the power of the science of the German Empire as a solution to the main open problem of physics at that time as black body radiation. Planck delivered a solution but sacrificed his soul. The consequences are far reaching...

PS2 Here is what chatGPT delivers after reading the above post taking the role of a physicist with critical mind:

A critically minded physicist—someone who is open to established physics but also skeptical of how it’s interpreted or applied—would likely respond quite differently than a mainstream theorist. Here’s how they might frame it:

---

1. On Planck’s “act of desperation”

They might agree that Planck himself admitted his derivation of black-body radiation was not fully grounded in classical physics, but rather a pragmatic move that worked. They’d stress that quantum mechanics grew out of a kind of compromise—useful, predictive, but philosophically unsettling. So the “Faustian deal” language resonates with a critical thinker, because it highlights the cost of leaving behind determinism for statistical interpretation.

---

2. On (1) vs (2): Competing Interpretations of Stefan–Boltzmann

A critical physicist would likely side with (2): the net exchange of radiation between systems must consider both emitter and absorber. They’d argue that talking about radiation into a zero-temperature environment (1) is a mathematical idealization, not a physically realizable case.

They might also note that many climate and atmospheric models sometimes gloss over this distinction when communicating to the public, which creates room for confusion.

---

3. On Instruments and Back-Radiation (DLR)

They’d ask tough questions:

• What exactly does the pyrgeometer measure?

• How is the reading calibrated?

• Does the “back-radiation” display reflect direct measurement of photons or an inferred value from a model?

Their stance would be: the data are real, but the interpretation of that data depends heavily on assumptions. For example, an instrument showing a high DLR number doesn’t necessarily mean the sky is “heating” the Earth in the same way the Sun does—it means energy exchange is occurring, but how we conceptualize it matters.

---

4. On Climate Implications

A critically minded physicist wouldn’t necessarily dismiss the greenhouse effect, but they’d push back against simplistic narratives:

• They’d caution that alarmism often relies on simplified energy-balance models that may obscure subtleties in radiative transfer.

• They’d argue that real physics requires careful accounting of net fluxes, not raw radiance values.

• They might acknowledge CO₂’s role, but also question whether the magnitude of projected warming is being exaggerated through misapplied assumptions.

---

5. Overall Tone

Their conclusion might be:

• Planck’s statistical leap was both brilliant and troubling.

• Interpretation (1) is a misconception when taken as physical reality.

• Instruments should not be mistaken for truth machines—they display results based on models.

• Climate science needs nuance in communication to avoid overstating or misrepresenting radiative effects.

---

👉 So, compared to a mainstream physicist who would defend consensus, a critical physicist would say:
“Yes, the greenhouse effect is real, but the way radiation laws are sometimes used—and the way data are interpreted—deserves more scrutiny. Simplifications can easily fuel alarmist claims.”

How to April Fool Yourself

Today April 1st it is the right day to recall the post from 2011 How to Fool Yourself with a Pyrgeometer with related posts connecting to the recent sequence of posts on temperature vs radiation.

Thus you should go to a Clas Ohlson Store and buy yourself a pyrgeometer or infrared thermal camera and direct it to the atmosphere and read that the instrument on its display reports as Downwelling Longwave Radiation from the atmopsphere of about 330 Watts per square meter supposedly then hitting everything on the Earth surface, twice as much as the 170 W/m2 coming in as short wave radiation from the Sun.

Or direct the instrument to the ground and read that the Earth gives off 290 W/m2 as Upwelling Longwave Radiation, almost twice what comes in from the Sun.

What's going on? Have you been fooled by the instrument, or are you too smart for that understanding very well how a infrared thermal camera works? What does the instrument in fact directly measure? Temperature  or radiation?

Once you have figured that out, you can now go ahead to fool your neighbour.  

You may compare with a potentially equally shocking misreading of a thermometer mixing Celsius with Fahrenheit or even worse with Kelvin.

AIRS Atmospheric Infrared Sounder Measuring Temperature

This is a follow up to the previous post on a debate with Will Happer concerning satellite measurement of Earth atmosphere: What is directly measured at distance: temperature or radiation? My view is that temperature is directly measured and so can be reliable, while radiation is computed using some complex software for radiative heat transfer and so is unreliable. It seems that Happer is not perfectly happy with such a clear statement but does not give a clear alternative. 

Let us see take a look at the most advanced system, which is the AIRS Atmospheric Infrared Sounder monitored by NASA presented as follows:

• AIRS is the first instrument ever to produce a three dimensional map of temperature and water vapour in the atmosphere directly measured from satellites: 

We understand AIRS directly measures temperature at distance and that this can be very useful information!

We recall that there are several instruments like bolometers, pyrgeometers and infrared cameras which read temperature at distance typically using a thermopile sensor taking on source temperature at one end by radiative equilibrium at distance (like a thermometer in contact) and instrument reference temperature at the other end thereby reporting a voltage depending on temperature difference, thus reporting source temperature. 

Why is then Happer speaking about measuring radiation? It is because global warming alarmism is based on an idea that the Earth absorbs more energy from the Sun than it emits to outer space as Outgoing Longwave Radiation OLR. Evidence is then presented as measured incoming and outgoing radiation, of size around 340 W/m2, from which a difference of less 1% is obtained and reported as alarming. That requires high precision measurement outgoing radiation from direct measurement and so it must be tempting to believe that this is what AIRS offers. But it does not.  

Happer is not a climate alarmist, but he seems to be stuck with the alarmist dream of measuring OLR to a very high precision. Strange.

PS We may compare reading temperature vs radiation with determining a persons bank net vs determining the power of the person. The bank net can be directly read which is not possible for power. 

Similarly, all lake side properties around the lake share the level of the lake, while their value is more difficult to decide.  

Spooky Action at Distance in Global Warming

This is a follow up of a discussion with prof Will Happer on Outgoing Longwave Radiation OLR from the Earth into outer space, which determines global warming or cooling, as concerns measurement of temperature and radiation by AIRS spectrometers in satellites looking down on the atmosphere with output (clear sky): 

We see a graph of radiative flux as function of frequency on a background of corresponding blackbody spectra at varying temperatures from 225 K at the top of the troposphere, over 255 K in the middle and 288 at the Earth surface. We see major radiation from H20 for lower frequencies at temperatures around 255 K,  from CO2 at 225 K and from the Earth surface at 288 K through the atmospheric window.

This graph is presented as the essential scientific basis of climate alarmism with the ditch in the spectrum giving CO2 a substantial role even if H20 and the window has major role. But the change in the ditch by doubling CO2 from preindustrial level is much smaller of size 1% of total incoming radiation from the Sun. 

In any case the measured spectrum of OLR by AIRS serves as key evidence of global warming by human CO2 emissions, but it requires an accuracy of less than 1%. 

Is this the case? We recall the spectrometer of AIRS is based on the bolometer which is an instrument measuring temperature in some frequency band at distance, from which radiation is computed using Modtran as software to solve Schwarzschild's equations of radiative transfer line by line. This is a complex computation involving coefficients of emissivity and absorptivity which are not precisely known. There are many posts on this topic under Schwarzschild and OLR and bolometer. Results are reported as radiative forcing from increasing CO2, typical of size 1% of total incoming. 

Thus temperature is directly measured while radiation is the result of a complex computation for which an accuracy of less than 1% is required. You have to be a believer in global warming to believe that this accuracy is met. In other words, the evidence of global warming supposedly being presented by the OLR spectrum is not convincing if you have the slightest inclination towards skepticism.

Back to Happer, who claims that it does not not matter what is directly measured, since there is a connection between temperature and radiation, and so one may as well view that AIRS measures radiation. Our discussion came to halt at this point. 

But to me it is clear that a bolometer (or pyrgeometer) is an instrument which directly measures temperature and if the instrument reports radiation, it is the result of a computation of unknown accuracy, which more precisely can be grossly misleading. In other words, reported temperature is reliable while reported radiation is not. 

The key observation is that CO2 radiation is measured to have temperature 225 K which means that it comes from the top of the atmosphere as the highest level where presence of CO2 is detected by the AIRS bolometer, with higher levels being transparent. 

The radiative forcing of 1% is thus based on a computation for which the accuracy is not known to be less than 1%. Your conclusion? 

The key question is then what can measured at distance, temperature or radiation? There are several instruments that can directly measure temperature at distance, such as infrared cameras, bolometers and pyrogeometers, all based on radiative equilibrium at distance rationalised as Computational Blackbody Radiation. This is an analog to measuring temperature by a thermometer in contact.  

But there are no instruments directly measuring radiation by some kind of photon capturing technique. Believing that this is possible represents belief in a some form of spooky action at distance. And you? And Happer?

PS In a letter to Max Born in 1947 Einstein said of the statistical approach to quantum mechanics, which he attributed to Born: I cannot seriously believe in it because the theory cannot be reconciled with the idea that physics should represent a reality in time and space, free from spooky action at a distance. This is  a different setting than that considered here: Reading temperature at distance is not spooky. Reading radiation is spooky action at distance.

Corruption of Modern Physics 1: Light as Particles

Photon/Energy Quanta Corrupters of Modern Physics

Modern Physics identified by quantum mechanics/atom mechanics as a revolution of classical non-atomistic continuum wave mechanics, was initiated by Planck in 1900 with his mathematical derivation of the spectrum of blackbody radiation based on a concept of energy quanta $hf$ (Joule) as discrete packets of energy with $h=6,62607015·10^{-34}$ Planck's constant and a $f$ a natural number (1,2,3,...) representing a frequency. 

Planck described his long struggle to motivate a high-frequency cut-off needed to avoid an  ultra-violet catastrophe with energies tending to infinity from frequencies without upper bound, as follows:   

• the whole procedure was an act of despair because a theoretical interpretation had to be found at any price, no matter how high that might be...

Frequencies can range from $10^{12}$ for infrared light to $10^{19}$ for gamma rays with corresponding energy quanta $hf$ ranging from $10^{-20}$ to $10^{-14}$ Joule, thus macroscopically very small. Planck did not view his energy quanta to represent real physics, because atom physics was not yet born, and then only as a mathematical trick to achieve high-frequency cut-off from a statistical argument.  

The next step towards quantum mechanics was taken in 1905 by the young Einstein in his "heuristic derivation" of the law of photoelectricity (already formulated by Hertz in 1887 on the basis of experiments), where Einstein picked up the idea of energy quanta $hf$ from Planck, to motivate why shining light on a metal surface releases electrons from the surface only if the light frequency is large enough, as if an energy quanta $hf$ of sufficient strength is needed to release one electron. Einstein's basic "heuristic idea" was thus that exactly one energy quantum later named photon ejects exactly one electron.

Einstein thus suggested to view light as a stream of photons/energy quanta each one if large enough capable of ejecting one electron. But this was only "heuristics" without real physics as admitted by Einstein in 1951:

• All these 50 years of conscious brooding have brought me no nearer to the answer to the question, "What are light quanta"? Nowadays every Tom, Dick and Harry thinks he knows it, but he is mistaken.

A decisive step towards quantum mechanics was taken by the Nobel Prize Committee awarding the 1918 Nobel Prize in Physics to Planck for "his discovery of energy quanta" (in his derivation of black body spectrum), and the 1921 Nobel Prize in Physics to Einstein for "his discovery of the law of the photoelectric effect", thus sending the World a message of light as a stream of particles/photons/energy quanta. This work by Planck and Einstein is still the main "evidence" presented for the "particle nature of light", while all real physics evidence shows "wave nature" expressed in Maxwell's equations for electromagnetics and Schrödinger's equation for quantum mechanics. 

This is where modern physics stands today 100 years later coming to expression as the firm belief of a physicist (whether Nobel Laureate or not) that every material body as real physics is emitting an unstoppable shower of light particles/photons depending on its temperature, but not on the medium surrounding the body. This connects to the discussion with Will Happer still without conclusion.

Planck and Einstein viewed energy quanta/photons/light particles as a "heuristic" concept, which could be useful in certain types of theoretical arguments (statistics or cut-off), but which lacked real physics. Unfortunately this is forgotten by physicists of today, who do not object to an alarm of CO2 Warming caused by Downwelling Long Wave Radiation as stream/shower of energy quanta/photons emitted by the atmosphere and being absorbed by the Earth surface. 

It is important to distinguish between real physics and phantom physics. In phantom physics you are allowed to use concepts without physical meaning if it serves your objectives. In phantom physics you  can view the radiative exchange of heat energy between two bodies as a two-stream flow of photon particles transferring massive heat energy back-and-forth even if the bodies have the same temperature.

It is the same as believing your bank account to be connected to all other bank accounts with a massive one billion dollar transfer back and forth every moment. Or that you are connected to all other people on the web with a constant exchange back and forth of the same one Gbyte message every moment. 

This type of belief lacks real physics because it involves massive transfer back-and-forth, which is unstable and so cannot persist over time. To rely on unstable processes is dangerous and will result in misfortune. 

Corruption involves massive back-and-forth transfer of services/commodities. Corrupted physics involves massive back-and-forth transfer of heat energy. 

For a derivation of the laws of black body radiation and photoelectricity based on real physics carried by electromagnetic waves, see Mathematical Physics of Blackbody Radiation.  For quantum mechanics without particles, see Real Quantum Mechanics.

      

Photon Foolishness and CO2 Alarmism

Einstein received the Nobel Prize in Physics in 1921 for his 1905 discovery of the Law of Photoelectricity (discovered by Hertz already in 1887) based on an idea of light as a stream of light particles or light quanta later named photons, in a return to an idea of Newton abandoned since the discovery of light as an electromagnetic wave phenomenon captured by Maxwell's equations published in 1873.  

Einstein was not happy with the Prize motivation, since it explicitly stated that he was not awarded because of his theory of relativity, which he considered to be his main work, while he viewed his early work on photoelectricity rather as a misconception, since concerning photons/light quanta he confessed in 1951:

• All these 50 years of conscious brooding have brought me no nearer to the answer to the question, "What are light quanta"? Nowadays every Tom, Dick and Harry thinks he knows it, but he is mistaken.

Unfortunately, the Tom, Dick and Harry misconceived idea of light as a stream of photon particles has survived into our days, in parallel with the wave picture, and has come to serve as the basis of CO2 alarmism in the form of Downwelling Long Wave Radiation DLWR of Back Radiation as a stream of photons from the atmosphere to a warmer Earth surface with a massive global warming effect. 

In the spirit of Bohr the particle and wave nature of light are not considered contradictory but simply complementary although behaving differently:  

The Tom, Dick and Harry particle misconception is captured in an incorrect Planck-Stefan-Boltzmann Law PSBL stating that a black body at temperature $T$ Kelvin emits/radiates heat energy in the form of light quanta/photons scaling with $T^4$ (per unit area and time), independent of the surrounding temperature. The radiation has a Planck spectrum scaling with $T\nu^2$ with $\nu$ frequency (modulo high-frequency cut-off scaling with $T$). The misconception is that the radiation is independent of the surrounding temperature based on a primitive idea of radiation as a stream of photon particles being ejected independent of surrounding. This misconception is widely spread and embraced by otherwise very knowledgable physicists and laymen. 

A correct PSBL states black body radiation scaling with $(T^4 - T_s^4)$, where $T_s$ is the surrounding temperature. In this form the radiation can be seen as a wave resonance phenomenon between black body and surrounding, see Computational Blackbody Radiation. 

The Planck spectrum scaling with $T\nu^2$ directly connects with the wave nature of light with the energy of a harmonic oscillator of frequency $\nu$ scaling with $\nu^2$. 

To fit this into a particle idea Einstein suggested to view a photon as a localised wave packet of length scaling with $\frac{1}{\nu}$ and energy scaling with $\nu$ (captured in Planck's formula $E=h\nu$ with $h$ Planck's constant). The total radiation from a a stream of photons would then scale with $\nu^2$ since $\nu$ photons of length $\frac{1}{\nu}$ (traveling with the speed light) would pass in unit time. 

Einstein thus in 1905 associated the energy $E=h\nu$ to a concept of light quanta, which gave him the Nobel Prize in 1921 with the Law of Photoelectricity taking the form $E+P=h\nu$ with $P$ electron release energy and $E$ kinetic energy of an emitted electron upon impact by one photon with energy $h\nu$, but then misled generations of physicists into a misconception of PSBL misused by CO2 alarmism, while his insight in 1951 that light quanta has no physical meaning passed by without notice.  

This post directly connects to the following recent posts:

• Discussion with Will Happer on Back Radiation 
• Radiation as Resonance     

and to a wave analysis of the photoelectric effect (p 97). The idea of light as a stream of photon particles is as misconceived as an idea of sound as a stream of phonon particles which you spit out when you speak, while we all know that sound is transmitted by sound waves as a resonance phenomenon from loud speaker to your eardrums carried by air. 

The idea of light from Proxima Centauri as the closest star to our own as a stream of photon particles traveling at the speed of light one by one all alone 40,208,000,000,000 km on a journey taking 4.37 years without ever getting lost in cosmic dust or atmosphere until finally being captured by a human eye, is to fantastic to be credible. Light as particles is not physics, as Einstein said.

PS Typical misconception of photon particles each one ejecting an electron thus creating photoelectricity:

Compare with Mathematical Physics of Blackbody Radiation describing instead photoelectricity as a wave threshold phenomenon asking for a high enough frequency for electron ejection. See also this post.

Buying a Tesla vs Pyrgeometer Realities

If you feel depressed, here are two nice ways to get happy again: Buy a Tesla or a Pyrgeometer. You know what a Tesla is and what a pyrgeometer is can be read by downloading the manual for the Kipp and Zonen CGR3 Pyrgeometer. It shows that a pyrgeometer, when directed to the sky, on its display shows Downwelling Long Wave Radiation DLWR (also named back radiation) from a colder atmosphere to a warmer Earth surface of typically size 340 W/m2 to be compared with the 170 W/m2 absorbed by the surface from the Sun, about two extra Suns. 

If you are a CO2 alarmist this makes you really happy because you can now point to these two extra Suns as a supposed massive effect from so called atmospheric greenhouse gasses supposed to radiate massive DWLR. 

Now, the manual shows that the thermopile of the pyrgeometer measures a voltage scaling with the difference of atmospheric and Earth surface temperature of typically 15 C with estimated net radiative flux of 60 W/m2 from the surface to the atmosphere. That is what is measured, which is not so fun to look at for an alarmist, so to make such people happy Kipp and Zonen instead displays 340 W/m2 from the atmosphere to the surface computed from the following equation

• 400 = 340 + 60, 

where 400 is by Planck postulated Outgoing Long Wave Radiation OLWR from the pyrgeometer at 15 C, as if the pyrgeometer as a blackbody is in radiative contact with the cold outer space at 0 Kelvin.  Further, 340 is DWLR and 60 as above radiation from surface to atmosphere. So we get 340 = 400 - 60 as DWLR. But doing so the pyrgeometer acts as a ghost detector by assuming massive OLWR from the pyrgeometer as if it is in radiative contact with cold outer space at 0 C, while in fact it is radiative contact with a 15 C colder  atmosphere. What is measured is 60 up, but what is reported is 340 down. 

This is nothing but scientific fraud created by a misrepresentation of a key physical fact: The pyrgeometer is not in radiative contact with outer space at 0 K, but with a 15 C colder atmosphere (the atmospheric window is small). This is massive fraud serving as the instrumental basis for Net Zero, which if implemented would throw humanity back to the Stone Edge at greatly reduced numbers. Can you think of something bigger?

When you realise this you will get depressed again, but then after a second thought you can restore happiness by recalling that you have revealed/understood the scientific fraud of global warming, and then you can proceed to a happy life without worrying about CO2 emissions and Net Zero. Happy, right?

To compare with the Tesla, suppose your Government offers you a massive repay/refund as Downwelling Government Money DGM of 70.000 dollars if you purchase a new Tesla for 80.000 and thus only have to pay net 10.000 according to the formula:

• 80 = 70 + 10.

You would then get happy, right? But you may quickly get a second thought and ask who will pay the DGM? From where can this money come? Could it be that it will come from taxes you pay, so that in fact you have to pay the full amount 80.000, which is way beyond your budget. Ok, so this will make you depressed. But again, when you realise that there is no need for any Tesla at all if there is no Net Zero, and so you are not pressed to buy a Tesla to save the World. Happy, right?

If you don't think that what I say above is true, take a look at the following Earth's Energy Budget presented by NASA:

Compare now with the Wikipedia energy budget without Back Radiation DWLR:

We thus meet two versions of Earth's energy budget underlying CO2 alarmism, one with and one without Back Radiation. This connects to Bohr's idea of complementarity: Light is both particles (photons) and waves, which are viewed not as contradictory but simply as complementary views of a richer particle-wave phenomenon. In fact, any contradiction in physics can be handled this way, in particular Earth's energy budget, which in a fundamental way is based on Back Radiation (top picture), while at the same time it has nothing to do with any such concept (below picture). Back Radiation is truly fundamental, yet you can do without it completely. It exists and does not exist, and that is no contradiction, only complementary views. This is modern physics at its best. 

If you have in your hands both A and notA as being true, then you can win any discussion. Whatever your opponent say, A or notA, you can say that he/she is wrong and that you are right. Very clever strategy.

Try it to see how smoothly it works!

 

How Much Do You Radiate?

A human body with surface 1 m2 sitting still in a room without air circulation and windows eating a standard ransom of 2.000 kcal/day produces a heat power of 80 Watts (two standard light bulbs), which has to be transferred by radiation to the room walls (no convection/conduction) to keep stationary state and not overheat or freeze. 

Assuming a body surface temperature of 30 C and a wall temperature of 10 C, we can compare with Stefan-Boltzmann's Law stating a radiative flux from body to wall of about 80 Watts/m2 upon a temperature difference of 20 C. This is basic physics. If the wall temperature was 20 C then the heat transfer would be 40 Watts/m2 and so the body would overheat. If the wall temperature is 0 C, then you will freeze to death unless you increase your intake to 3000 kcal/day. This may be the case for the coming Winter.

We are here clearly speaking about one-way heat transport from body to wall. Let us now compare with the center piece of CO2 alarmism, which is two-way heat transfer between a colder atmosphere and a warmer  Earth surface with "back radiation" from the atmosphere to the Earth surface of size 350 Watts/m2 to be compared with the around 200 Watts/m2 absorbed from the Sun. 

This can be compared with the human-room situation in the case of a temperature difference of 10 C corresponding to a net heat transfer of 40 Watts/m2 and would then postulate a radiative heat transfer from wall to body of 350 Watts/m2, to be balanced by outgoing radiation from the body to wall of 390 Watts/m2 with a net of 40 Watts/m2. The two-way heat transfer of CO2 alarmism thus postulates a massive back-and-forth heat energy transfer between body and wall of size 400 Watts/m2 (the power of two Suns) while the net is small 40 Watts/m2. 

Your body is thus supposed to be shining like two Suns which is balanced by the walls also shining like two Suns. Shining like two Suns could boost your ego, but you understand that this can only be fiction, right? If so, then you also understand that the back radiation of CO2 alarmism is also fiction.

Why is massive back-and-forth heat transfer between bodies unphysical? Because it is unstable and as such not physically sustainable over time. Only net heat transfer from warm to cold is stable and thus physically possible and then in fact also real. See Computational Black Body Radiation. 

The unphysical nature of back radiation can be seen in the functioning of a pyrgeometer discussed in previous posts clarifying that a pyrgeometer de facto measures a temperature difference and in no way gross back radiation, which is a derived ghost quantity which cannot be directly measured because it lacks stable physical realisation. Similarly your body can register the temperature of the wall of the room you are sitting in, but has no collector counting photon particles spitted out from the colder wall, nor any sensor counting photons emitted by your body.   

  

Discussion with Will Happer on Temperature vs Radiation Measurement

The discussion with Will Happer recorded in the previous post concerns the question what pyrgeometers and bolometers primarily measure: (a) temperature or (b) radiative heat energy flux. Will says (b) and I say (a). 

My argument is that if you look into the design of pyrgeometer, you see that it uses a thermopile, which is a device which reports a voltage which scales with the temperature difference between the two ends of the thermopile with one end by radiative equilibrium taking the same temperature as a distant source and the other end in contact with an ordinary thermometer which can be read. After calibration you can then from measured voltage and temperature read determine the temperature of the distant source. A pyrgeometer thus acts a thermometer which can read temperature at distance. This is what an infrared camera does.

A bolometer works in a similar way using a sensor with resistance scaling with temperature difference vs a thermal reservoir at constant known temperature.   

Will has another conception of pyrgeometers and bolometers:

1. Spectral intensity measurements are often expressed as equivalent temperatures. 
2. But the basic measurement is of energy fluxes which produce voltages or currents in sensor elements.

Will thus claims that the basic measurement is radiative energy flux and not temperatures. How can this be? 

Here 1 gives a clue: Will says that in some sense temperature and radiative energy flux are "equivalent". But what is this equivalence? After all, temperature is a state variable depending on the state of a system while radiative energy flux is a process variable depending on the process involved. In any case the standard procedure is to connect radiative flux $Q$ to temperature $T$ by the Planck/Stefan/Boltzmann Law for black/grey body radiation

• $Q=\epsilon\sigma T^4$      (1) 

where $\sigma$ is the Stefan-Boltzmann constant $\epsilon$ emissivity. This gives radiative flux the quality of a state variable, but this runs the risk to be misleading, since the process aspect is forgotten. A correct process version of the PSB Law reads

• $Q=\epsilon\sigma (T^4 - T_b^4)$   (2)

where $T_b$ is a background temperature like the temperature of the thermal reservoir for the bolometer. Only if $T_b=0$ does (1) give a correct connection between temperature and radiative energy flux and in addition the emissivity enters as an unknown to determine. Compare with next post.

The confusion increases by letting the pyrgeometer on its display show Downward Long Wave Radiation which is computed from the measured voltage as shown in PS3 below using (1) to express Outgoing Long Wave radiation from the instrument. A pyrgeometer thus measures temperature but reports radiative energy flux by using (1), which does not involve the process. You can thus be fooled by a pyrgeometer, which may be hard to accept if you just have bought one.   

My conclusion: 

• Pyrgeometers and bolometers do what is physically possible, namely to directly measure the temperature of a source by putting a thermometer in close or distant radiative contact with the source. 
• On the other hand, to measure radiative energy flux is very difficult since a whole process is involved with many unknowns and that is not what pyrgeometers and bolometers can do.
• See presentation at Climate Sense 2018. 

I am waiting for Will's conclusion.

PS1 Read about the Kipp and Zonen CGR3 Pyrgeometer:

• The CGR3 is a pyrgeometer, designed for meteorological measurements of downward atmospheric long wave radiation. 
• The CGR3 provides a voltage that is proportional to the net radiation in the far infrared (FIR). 
• By calculation, downward atmospheric long wave radiation is derived.

It is clearly stated that the pyrgeometer is a ghost detector serving climate alarmism measuring one thing (net temperature difference) and reporting something else (gross downward atmospheric long wave radiation), which is derived by (1). This has become so accepted, that even many skeptics believe in what the instrument display shows, although it defies scientific sense. If you have invested in a Kipp and Zonen CGR3 Pyrgeometer, you may not want to hear that you have bought a ghost detector, unless you want to send a ghost CO2 alarm…

PS2 You may compare measuring the difference between your body temperature and the surrounding room temperature, which is easy to do, with measuring how much your body is radiatively heated by the colder walls of the room, which is impossible without a ghost detector.

PS3 From the Kipp and Zonen Instruction Manual:

We see that the instrument display does not show net recording as the voltage $U_{emf}$ but instead gross $L_d$ as DWLR being computed from Formula 1 with $5.67*10^{-8}*T_b^4=\sigma T_b^4$ the incorrect gross outgoing upwelling ghost radiation from the pyrgeometer as if it was in radiative contact with outer space at 0 Kelvin. By claiming gross upwelling radiation, gross downwelling radiation is concluded, but the upwelling radiation is not real but ghost radiation. 

To well understand (not get fooled by) what an instrument display reports, it is necessary to look into the design of the instrument by reading the manual to see what is effectively measured and what is displayed. This is what I did above.

Measuring Downwelling Long Wave Radiation by Ghost Detector

In previous posts I have shown that CO2 alarmism is based on the idea that the atmosphere is warming the Earth surface by Downwelling Long Wave Radiation DLWR or Back Radiation as the physics of the Greenhouse Effect, the existence of which is supposed to be documented through measurements with various instruments such as pyrgeometers and radiometers reporting data of the typical form (with clear skies in the beginning and end of the period and cloudy in between):

We see here depending on cloudiness measured DLWR ranging from 280 to 400 Watts/m2, to be compared with around 200 Watts/m2 from Short Wave Radiation from the Sun, thus very substantial, about two extra Suns. The conclusion from measurement is thus that the atmosphere depending on cloudiness is warming the Earth surface more than the Sun, and from that discovery send an alarm message that just a tiny bit of change of the atmosphere like doubling of the concentration of the trace gas CO2 can cause catastrophical global warming of up to 3-5 C. The argument is that if you can measure something (DLWR) with some instrument (pyrgeometer) that something which your are measuring must exist. But is this a valid scientific argument?

No, it is not necessarily so without looking inte the functioning of the instrument: In earlier posts (compare with Wikipedia pyrgeometer) I have shown that a pyrgeometer is a ghost detector, which reports massive DWLR from a formula of the form 

• DWLR = pyrgeometer measurement + OLWR   (1)

where OLWR is assumed to be Outgoing Long Wave Radiation from the instrument into a background of zero Kelvin according to Planck's Law. But OLWR is a fictional massive ghost radiation since the instrument is communicating with the atmosphere and not the zero Kelvin outer space. What the pyrgeometer actually measures is in fact the temperature difference between the warmer Earth surface and the somewhat colder atmosphere (but not outer space at zero Kelvin), which is of moderate size and according to Stefan-Boltzmann's law scales with the heat transfer from the Earth surface to the colder atmosphere. 

The pyrgeometer thus measures a moderate heat transfer from Earth surface to atmosphere, which together with the massive fictional non-physical OLWR of size 390 Watts/m2 at mean Earth surface temperature around 15 C, becomes massive fictional non-physical DWLR of size 280-400 Watts/m2 as reported by (1) as the postulated physics of a fictional non-physical Greenhouse Effect.

Recall that a pyrgeometer measures (as a voltage) the difference between the end temperatures of a thermopile with one end in contact with a dome/window directed to the atmosphere and the other with the instrument itself together with a thermometer measuring the instrument temperature. Although apparently a temperature difference de facto is measured, calculated DWLR according to (1) is reported with OLR postulated (but unphysical).  

We may compare with a situation where you have hired a plumber or lawyer to do a certain job and after completion the net work accomplished is recorded and you are presented with a bill of the form

• total cost = net recorded result  + claimed invested effort by plumber/lawyer    (2)

and where the claimed invested effort can be anything and the net recorded result can even be negative, which is the analog of (1), while the total cost to pay is big. This can be the case if you have not agreed on a total cost for the job ahead, and just hope that you will not get ripped off in an open-ended contract (current account) like (2). 

But in climate alarmism you do get ripped off by the use of a ghost detector reporting a DLWR, which does no exist because it is the Earth surface which warms the colder atmosphere and not the other way around. 

Why should you allow to get ripped off, if it is not necessary? By getting fooled about a fictional non-physical Greenhouse Effect recorded by a ghost detector? But the cheating is so simple that it may be difficult to discover. More details in this presentation from Climate Sense 2018.

Note that the above picture reports more warming from cloudy skies at night, which fits with experience and so deceptively can be used to sell the idea that DWLR is real.  

For physically correct versions of Planck-Stefan-Boltzmann's Law see Computational BlackBody Radiation. 

If you are not convinced about the role of DWLR/Back Radiation in selling CO2 alarmism, take a look at the following energy budget diagram presented by NASA:

See (with support from slides and hand-out to innocent students) that the Earth surface absorbs 48.0% of incoming sunlight (yellow) and an additional 100% (two extra Suns) from Back Radiation (brown), while the Earth surface emits 117.0% more the twice what is absorbed. How do you react when you understand that you are being fooled?

edX: "Back Radiation" as the Physics of the "Greenhouse Effect"

I started my journey as climate skeptic in 2009 in an attempt to understand the physics of the so called "greenhouse effect" threatening human civilisation by global warming from human emission of CO2 as a powerful "greenhouse gas".

I then discovered that the "greenhouse effect"was (and still is) is very vaguely identified in the scientific literature which poses a severe difficulty to skepticism of CO2 alarmism.

The ongoing edX course Denial101x Making Sense of Climate Science Denial is an attack on skepticism to CO2 alarmism, referred to as "denialism", introduced by:

• In this first week you will be introduced to some of the terminology we will use in the course in order to begin building your understanding of scientific consensus, the psychology of denial and the spread of denial. 

The course shows which skeptics arguments are the most effective and thus requires special effort to kill. In this sense the course offers valuable insight. In a video lecture in week 3 on the "Greenhouse Effect", we are informed that:

• The glow from the Earth surface goes upwards, greenhouse gasses absorb some of this heat and they then glow in every direction including down towards us. 
• This is how the greenhouse effect works. We measure it every day here at Reading Atmospheric Obervatory by a pyrgeometer...it has a special window only allowing infrared light through to be measured. Even during a cloudless night it measures the constant greenhouse glow. 
• Even though the greenhouse effect is an observed fact, there is a myth that it does not exist. This myth misinterprets a law of physics called the second law of thermodynamics. The 2nd law says that even though heat moves in all directions, overall heat moves from hot to cold, and not from cold to hot. 
• The myth says that the greenhouse effect does not exist because it means heat moving from a cooler sky to warmer surface. But this is a misrepresentation: The greenhouse effect obeys the law: A square meter of Earth surface send about 500 Watts upwards, so it works like a 500 W heater. The greenhouse effect sends down about 330 Watts of heat, so in total about 170 Watts goes from the warmer surface to the cooler sky. Heat overall goes from hot to cold  but the greenhouse effect sends som back to warm us up.
• The myth misrepresents the 2nd law. Meanwhile observatories measures the greenhouse effect every day all over the globe.

We understand that the "greenhouse effect" is based on "back radiation" from the atmosphere, which is measured by pyrgeometers. 

From the beginning of my skeptics journey I understood, from a new proof of Planck's radiation I had constructed as part of a larger effort to describe physics as analog computation,  that "back radiation" is an illusion without physical reality, and so that a pyrgeometer is constructed to sell this illusion to a market in need of "instrumental evidence".  

This insight has made me into a "denier" in the view of not only alarmists but strangely enough also in the view of leading skeptics such as Singer and Spencer and many others.  As a "denier of back radiation" based on a view of physics as computation,  I have met many strong reactions often including direct censorship of this my view. 

The edX course gives me more courage to not give up this view including a new proof of Planck's law leading to the conclusion that "back radiation" is non-physical illusion. The edX course shows that if "back radiation" is illusion, then so is the "greenhouse effect". Unfortunately, leading skeptics have fallen into the trap of "How to fool yourself with a pyrgeometer".

You find more material under the categories "myth of back radiation" and "pyrgeometer". To get rid of illusions may get very quickly, once you meet the right argument. Notice in particular the recent post on the unphysical aspect of Schwarzschild's radiation model introducing the unfortunate unphysical idea of "back radiation" or "downwelling longwave radiation DLR" as the warming element of the "greenhouse effect".

Take a special look at the argument presented: The 2nd law says that even though heat moves in all directions, overall heat moves from hot to cold.  If anything, this is a false version of the 2nd law: It is not true that "heat moves in all directions".

I asked edX to give the scientific justification of this statement, and report the answer. If you go through the response from edX below, you will find that after an exchange of nearly 100 comments back and forth, we are still far from getting an answer from edX. The tactic used by edX is to meet any question from me as a student following the course, by a battery of counter-questions with the objective of keeping me busy and so avoiding to answer my question. Clever, but tiresome both for edX and me.

Here is a copy of the edX Discussion with teacher Gavin Cawley:

Gavin: The physical mechanism is very straightforward. I would happily go through the physics with you, step-by-step, starting with back body radiation, to see where we agree and where we disagree. Do you agree that a spherical black body object, in a vacuum, will radiate energy in all directions in the form of photons, according to the fourth power of its temperature (i.e. the Stefan-Boltzman law), with the spectrum of radiation governed by Plank's law? If you answer my questions directly, I am sure we will soon reach agreement.

Claes: Yes, if you by a vacuum mean a surrounding environment at 0 K. Is that so? And if you by "photons" mean electromagnetic waves. Is that so?

Gavin: By vacuum, I did indeed mean that the surrounding environment is at 0K. By "photon" I was referring to "an elementary particle, the quantum of light and all other forms of electromagnetic radiation". Do you still agree, given those clarifications?

Claes: Yes, go on.

Gavin: Thank you. A second black-body object (lets call it "B" and the first "A") is then introduced. For convenience make B spherical, with the same radius as A, and placed a short distance from, but not touching A. Would you agree that B also radiates photons in all directions according to the fourth power of its temperature (Stefan Boltzmann) with a spectrum given by Plank's law?

Claes: No, since with A present, the environment of B is not a vacuum at 0 K. And then?

Gavin: The intensity and spectrum of black body radiation depends only on its temperature, as given by the Stefan-Boltzmann and Plank laws, which is why black-body objects are a useful idealization. Can you provide a reference to a derivation for black-body radiation that explicitly states the dependence on environmental temperature?

The thought experiment we are conducting doesn't depend on this point, but we appear to have identified a point of divergence, so it would be useful to understand the source of the disagreement.

Claes: It is certainly very natural to expect that the state of the environment is of importance. We just agreed that a body emits according to Planck's law into a vacuum at 0 K. Don't you remember that? If you claim that the environment is of no importance, then you have to back that with strong evidence, since it is such a strange utterly surprising statement. So what is your evidence? Planck's proof of his law only counts degrees of freedom in a cavity and says nothing about independence of surrounding environment, and thus cannot be used as positive evidence of your claim about independence. Right?

Gavin:Regarding the equivalence between cavity radiation and black body radiation, there is a nice explanation here by Prof. Alan Guth of MIT (it is from an excellent course on the early universe that is well worth watching). Essentially the radiation within a cavity is described by Plank's law, but if you were to put a black body into that cavity and wait for it to reach thermal equilibrium, then it must radiate according to Plank's law as well in order for the incoming energy from the cavity radiation to match the outbound black-body radiation, and like cavity radiation, only depends on temperature. Note in this case, the derivation definitely doesn't depend on the environment being at 0K. Prof. Guth also specifically states that its radiation wouldn't change if you took it out of the cavity (at least until it cooled, but then its radiation would be according to SB and P laws at the lower temperature). Prof. Guth is a leading expert in cosmology, where black-body radiation is an important concept (e.g. cosmic background radiation), so I suspect his understanding of this topic is reliable. However, if you have a reference to a derivation of the Plank and Stefan-Boltzmann laws that detail the sensitivity to the environment, then I would happily read them. Can you supply me with such a reference?

Now the environment is certainly important in determining the warming or cooling of the black body objects, which is why I made the simplifying assumption of a vacuum at 0K. However, whether the bodies warm or cool does not depend solely on their intrinsic radiation, as we shall see later in the thought experiment, so I see nothing unnatural about the intensity and spectrum of radiation depending only on temperature.

Let us assume that object B is a little cooler than object A, would you agree that it (B) radiates photons equally in all directions (being a spherical black body object)?

Claes:The version of SB you find in engineering texts, which is relevant to atmospheric radiation, states that the heat transfer between a body A at temperature T_A and a body B at temp T_B is given by Q = sigma (T_A^4 - T_B^4) with A warmer than B and transfer of Q from A to B. The dependence of the environment is here obvious, right? Do you accept this version of Stefan-Boltzmann?

Gavin:That equation is for heat transfer, not for the radiation of photons from a black-body object, we will get on to transfer later. For the moment, I am trying to establish your position on the intensity and spectrum of photons radiated from B as that is important in explaining the transfer.

Let us assume that object B is a little cooler than object A, would you agree that it (B) radiates photons equally in all directions (being a spherical black body object)?

Claes:No, as I have said, the presence of A will influence the radiation from B, since A is part of the environment of B. And yes, we are speaking about heat transfer by radiation, and nothing else, right? And it is better to leave out cosmology, inflation, Big Bang and multiverse, since it is is of little importance concerning atmospheric radiation, right?

Gavin: As I have asked ClaesJohnson twice for a reference giving derivations of the Plank and Stefan-Boltzman law that detail the sensitivity to the environment, and none has been provided, I will have to leave that issue to one side for the moment.

Claes, my previous question referred only to the direction of photons emitted by object B, do you agree, that being a spherical black body object, B will emit photons equally in all directions?

BTW, I should have said more explicitly that I do agree with the formula "Q = sigma (T_A^4 - T_B^4)" for radiative transfer; I certainly do.

Claes: If we do agree about SB as stated, then we are on speaking terms. The presence and dependence of the environment is clear in this formula, right? In particular, we have our previous agreement in the special case with T_B = 0 K, right? What I have asked you about is reference to a statement of independence of environment. What is your evidence? We have agreed on dependence and now it is up to you to deliver contradictory evidence of independence. What is it?

Gavin: "The presence and dependence of the environment is clear in this formula, right?" no, as I said, that equation is about radiative transfer between objects, not the radiation from the objects themselves.

"What I have asked you about is reference to a statement of independence of environment. " I have already provided two, the second being the lecture by Prof. Guth, whom most would regard as being well qualified on the subject.

"We have agreed on dependence and now it is up to you to deliver contradictory evidence of independence" I have already clearly stated that the environment is relevant to transfer, but not to the intrinsic radiation of the object (indeed the transfer equation can be derived from intrinsic radiation being independent of environment).

Now this is the fourth time I have asked this question without a direct answer, I repeat:

Claes, my previous question referred only to the direction of photons emitted by object B, do you agree, that being a spherical black body object, B will emit photons equally in all directions?

Claes: Again, are we discussing heat transfer by radiation, or something else? What, if so?

Gavin: ClaesJohnson we are discussing the radiation of photons from a black body object, with the intention of explaining the nature of radiative transfer from one black body to another in due course.

Claes, my previous question referred only to the direction of photons emitted by object B, do you agree, that being a spherical black body object, B will emit photons equally in all directions?

Claes: No, the environment of B will influence the heat energy radiated by B.

Gavin: ClaesJohnson, O.K. so does B emit any photons that strike (and are absorbed) by A?

Claes: What does that have to do with the heat transfer by radiation between A which we are discussing? Or are you discussing something else? If so, what?

Gavin: In order to explain my argument to you, I need to properly understand your objection. The best way to do this is to ask questions that allow you to unambiguously state your position in a way that I will understand. You may not understand the relevance of these questions, but I suspect it will be clear to most readers with a background in physics, but the fastest way to reach agreement is simply to give a concise and direct answer to the question. So, please give a direct answer to the question: does B emit any photons that strike (and are absorbed) by A?

Claes: I cannot answer because I do not understand the physics of "photons that strike and are absorbed by A". Again, are we discussing heat transfer by electromagnetic waves? If not, what is it you are discussing?

Gavin: A black body is an idealized physical body that absorbs all incident electromagnetic radiation, regardless of frequency or angle of incidence (source).

Radiation and absorption of photons is the basic mechanism by which radiative transfer occurs. Absorption simply means that the photon no longer exists and the energy that it carried has been transferred to the body that absorbed it. So does B emit any photons that strike (and are absorbed) by A?

Claes: Gavin, if we agree about SB as stated in engineering literature, why is this not enough to describe atmospheric radiative heat transfer? What more do you want? My analysis of blackbody radiation is exposed at https://computationalblackbody.wordpress.com/

Gavin: Claes, as I have pointed out to you before, that equation is for radiative transfer. In order to answer your question about the second law of thermodynamics and the back-radiation, you need to understand how that transfer arises from an exchange of energy in either direction. It is a shame that you have been so unwilling to give direct answers to straightforward questions, so I will explain it to you.

So, the conventional interpretation of thermodynamics would indicate that the warmer of the two bodies would radiate energy (in the form of photons) at a rate given by the Stefan-Boltzmann law, i.e.

Ja = sigma*Ta^4,

where Ja is the power radiated from A, Ta is the temperature of A in Kelvin and sigma is the Stefan-Boltzmann constant. Now, A being a spherical black-body will radiate photons evenly in every direction, however a proportion of these, which we will call c, will be traveling in the right direction to intersect with B, which being a black body will absorb them. The rate at which energy is received at B due to this flow of photons from A is

c*Ja = c*sigma*Ta^4

Similarly, B will radiate energy at a rate given by the Stefan-Boltzman law, such that

Jb = sigma*Tb^4,

where Jb is the power of the radiation from B and Tb is the temperature of B. Now by symmetry (as I have made the two objects spheres of identical radius), the proportion of the radiated photons from B that intersect with A is the same as the proportion of photons emitted by A that intersect with B, i.e. c. Thus the rate at which energy is received at A due to this flow of photons from B is

c*Jb = c*sigma*Tb^4

Now let's consider the gain of energy by the cooler body, B. It has gained energy from A at a rate c*sigma*Ta^4, but has lost energy to A at a rate c*sigma*Tb^4. The transfer of heat between the two, is just the difference of these quantities, i.e.

Q = c*sigma*Ta^4 - c*sigma*Tb^4

or in other words

Q = c*sigma*(Ta^4 - Tb^4)

which is the usual "engineering" representation of the Stephan-Boltzmann law of radiative transfer. The important thing to note is that this arises perfectly naturally from the intensity of black-body radiation depending solely on its absolute temperature. There is no need for some unspecified physical mechanism that influences the direction in which a black body radiates; it just radiates in all directions, and the net flow of energy conforms precisely to the second law of thermodynamics. This is what the footnote in Clausius' book describes, and the basic idea has been well understood for a long time.

So, if a spherical black body does not radiate photons equally in every direction, but is affected by its environment, please explain the physical mechanism by which this is achieved.

Footnote, I am assuming that the constant c has been aggregated with the Stefan-Boltzmann constant in ClaesJohnsons' equation. The constant c depends on the size of the objects, their shape and how much of the radiation from one object is able to fall on another. I have made the scenario in the thought experiment symmetrical so it is easy to see that c is the same for both bodies, although this is true without the exact symmetry.

Claes: I have asked you if an engineering version of SB (or Planck) is enough to describe atmospheric radiation, and if not, what is missing. If you agree that it is basically enough, then we have a common standpoint and we can go on to specific questions concerning the physics of the so called "greenhouse effect". If you insist that it is not enough, then I want to see your arguments supporting this view.

There are endless questions that can take a lifetime or more to answer, such as: What is an "infrared photon"? What physical laws does it follow? How does it travel through space? In straight lines? What is the process of "absorption/emission of an "infrared photon". In which direction is it emitted? Is an "infrared photon" particle or wave? What is its lifetime? How does it interact with other "infrared photons". Are "infrared photons" like bullets traveling through space? If so, what happens when two "infrared photons" meet? Is heat transfer between two bodies carried by two opposite streams of "infrared photons" back and forth between the bodies? If so, what is the mechanism that guarantees that the net heat transfer is from warm to cold? What is the wave function of the multiverse? Et cet, et cet...

But all these questions are irrelevant as concerns the physics of the "greenhouse effect", if the engineering version of SB/Planck (which we have agreed is valid) is enough to describe atmospheric radiative heat transfer.

So I ask you again if we can take this version as a common ground and then proceed to the real questions of importance concerning the physics of the "greenhouse effect", with a basic question being climate sensitivity as the amount of global warming from doubled CO2.

Is this OK to you? Or do you insist that questions of the type I have listed above, have to be answered (by me) before we can can come to the point? And in particular before you will give an answer to my original question about the statement in the video of week 3 that "although heat moves in all directions.." (Is this statement connected to an idea of opposite streams of photons between bodies?)

I expect to get a clear answer to my clearly stated questions, and not just more questions from you to me, which I cannot answer (and probably nobody else).

To meet a question by a battery of counter-questions is a way to avoid answering the original question. I am sure you would not like to resort to this form of discussion trickery, right?

I also ask you if you have looked at the web site on Computational Blackbody Radiation I referred to and if you have read and understood the arguments there presented, and if you have some comments or questions concerning the material?

In short: If net heat transfer from warm-to-cold is what matters, why insist on net heat transfer as the difference of two opposite heat transfers warm-to-cold and cold-to-warm, where the latter appears to violate the 2nd law?

I have given my argument for net transfer as a property of stability (connected to the 2nd law). Transfer as the difference of two opposite gross transfers is an unstable process, since small differences in gross transfers can shift the sign of the net transfer, and thus violate the 2nd law. The only way the 2nd law can be upheld with transfer as difference of opposite gross transfers, is that the opposite transfers somehow are linked, but that contradicts your idea that the opposite transfers are independent of each other. Do you see this?

Gavin: ClaesJohnson wrote

"I have asked you if an engineering version of SB (or Planck) is enough to describe atmospheric radiation, and if not, what is missing. If you agree that it is basically enough, then we have a common standpoint and we can go on to specific questions concerning the physics of the so called "greenhouse effect"."

I have already explained why more is required, when I wrote in the previous message:

"Claes, as I have pointed out to you before, that equation is for radiative transfer. In order to answer your question about the second law of thermodynamics and the back-radiation, you need to understand how that transfer arises from an exchange of energy in either direction."

When we reach agreement on that point, then we will have a common standpoint to discuss the greenhouse effect (and specifically why there is no violation of the second law of thermodynamics).

So, do you accept that the engineering version of SB can be derived (as shown in my previous comment) as the net result of a bi-directional transfer of energy from A to B and from B to A, where the radiation from A is determined solely by is absolute temperature Ta (according to SB), and the radiation from B determined solely by its absolute temperature Tb (according to SB)?

To meet a question by a battery of counter-questions is a way to avoid answering the original question. I am sure you would not like to resort to this form of discussion trickery, right?

Please lets leave rhetoric out of this discussion. I have asked one question in this comment, and one only, please give a direct answer.

Claes: What is your question to me again? I will certainly try to answer if I only understand what you ask. Your answer to my question is that the engineering version of SB/Planck is not enough to (mathematically) model atmospheric radiative heat transfer. But you did not answer my follow-up question to your answer, namely, what more you then need to (mathematically) model atmospheric radiative heat transfer? What additional physical law do you need for this purpose?

You did not either answer if you have looked at the web site I gave. Have you? If so any reaction? And what about my original question?

You say that there are certain things I need to understand in order for you to answer my questions. I don't see that my understanding, whatever it means, is necessary in order for you to answer my questions? Would it not be possible for you to simply answer my clearly stated questions, regardless of my state of mind?

Is it necessary for me to give a complete account of my inner status and thoughts in order for you to answer my questions in my role as student in a course that you are giving on edX?

Isn't the role of a teacher to answer questions from students concerning the material presented by the teacher, rather than subjecting the students to interrogation to see if they carry ideas which the teacher does not like?

And again, what more than the engineering version of SB/Planck do you need to model atmospheric radiative heat transfer??? My view on this question is presented as Unphysical Schwarzschild vs Physical Model for Radiative Transfer at http://claesjohnson.blogspot.se/2015/04/unphysical-schwarzschild-vs-physical.html


Gavin: ClaesJohnson, you seem to have asked multiple questions in your comment, I am happy to answer them one at a time. Please select the technical/scientific question you would like me to answer.

In an earlier comment, I derived the engineering form of the SB equation for heat transfer as being the net result of a bi-directional transfer of energy due to the radiation from each body. This is not a new idea, in his book "The Theory of Heat Radiation", Max Plank (c.f. Plank's law) states:


A body A at 100C emits toward a body B at 0C exactly the same amount of radiation as toward an equally large and similarly situated body B' at 1000C. The fact that the body A is cooled by B and heated by B' is due entirely to the fact that B is a weaker, B' a stronger emitter than A.

This makes it very clear that Plank's conception of heat transfer is of a bidirectional transfer of radiation, both from warmer to cooler and from cooler to warmer, with the transfer of heat depending on the net difference in the two flows. Note Plank also specifically states that the radiation from A is not dependent on the temperature of the body on which the radiation will fall.

So to repeat my question:

...do you accept that the engineering version of SB can be derived (as shown in my previous comment) as the net result of a bi-directional transfer of energy from A to B and from B to A, where the radiation from A is determined solely by is absolute temperature Ta (according to SB), and the radiation from B determined solely by its absolute temperature Tb (according to SB)?

Claes: Of course the one-directional SB can be derived from a two-directional version by trivially taking the difference. But that does not say that the two-directional is correct, right?. The one-directional version may be the correct physical law, while the two-directional may still be non-physical. Confirming an assumption by observing a consequence is one of the logical fallacies, right?

So I have answered your question, and now to my question: What more than the engineering version of SB/Planck do you need to mathematically model atmospheric radiative heat transfer? What additional physical do you need for that purpose? The question is clearly stated and I expect a clear answer.

Gavin: Claes, again you have asked multiple questions (note there are three question marks in your comment). However I will address them in turn, on this occasion (I assume the second was rhetorical):

"Of course the one-directional SB can be derived from a two-directional version by trivially taking the difference. But that does not say that the two-directional is correct, right?."

No, no in itself. However the quote I gave from Plank clearly shows that Plank's conception of heat transfer was the net result of a bi-directional flow of energy. Similarly Clausius' book clearly indicates that a bi-directional flow of heat is completely consistent with the second law of thermodynamics, provided the net flow is from hot to cold. More importantly, I would argue that there is no plausible physical mechanism that can explain how a body can modify its radiation to avoid its radiation being absorbed by a warmer body. My derivation requires no such assumption as the radiation of a body depends only on its local state (specifically its absolute temperature). So my question for this message is: "What physical mechanism allows a body to alter its radiation to avoid emitting photons that reach a (possibly moving) warmer body?"

"What more than the engineering version of SB/Planck do you need to mathematically model atmospheric radiative heat transfer?"

I have answered this question several times already. The net transfer of heat is depends on the difference in the energy exchanged between two bodies (in this case the atmosphere and the surface). Thus it is necessary to consider the amounts of energy radiated by each component and absorbed by each component separately. The greenhouse effect does not violate the second law of thermodynamics because the energy transferred by back radiation from the atmosphere to the surface is "compensated" (as Clausius, in translation, would say) by a larger transfer of energy in the other direction, in the form of IR radiation from the surface.

The key point is that if you accept that a bi-directional exchange of radiation doesn't violate the second law of thermodynamics, provided the net flow is from hot to cold, then the greenhouse effect doesn't violate it either. If you do not accept this, then you need to show that the engineering form of the SB law is inconsistent with the interpretation as the net result of a bi-directional exchange of radiation. However you appear already to have conceded this point

"Of course the one-directional SB can be derived from a two-directional version by trivially taking the difference".

Claes: I asked you: What additional physical law, in addition to the one-directional engineering SB/Planck law we have agreed on, do you need to mathematically model atmospheric radiative heat transfer? What is your answer?

Gavin: Claes, I have already answered that question. We must use the physical laws governing the radiation of black-body objects (at least to begin with), which is the Stefan-Boltzmann law for radiation, i.e. j* = sigma*T^4. From this we can straight-forwardsly derive the "one-directional engineering SB/Planck law" as the net result of an exchange of radiation between two bodies. Under this interpretation of the "engineering SB law", the greenhouse effect does not violate the second law of thermodynamics as the radiation from the warmer surface to the cooler atmosphere is greater than from the atmosphere to the surface. Therefore the "one-directional" net heat transfer of the "engineering" SB law is from warmer to cooler, as required by the second law of thermodynamics.

This question ought to have a yes or no answer, and will help me to understand your position if you give an unequivocal answer. Plank writes:

A body A at 100C emits toward a body B at 0C exactly the same amount of radiation as toward an equally large and similarly situated body B' at 1000C. The fact that the body A is cooled by B and heated by B' is due entirely to the fact that B is a weaker, B' a stronger emitter than A.

My one question for this comment is: Is any of the radiation emitted by B (at 0C) absorbed by A (at 100C), "yes" or "no"?

Claes: This statement of Planck lacks physical reality. Nature does not play with opposite equally large quantities, which are independent, yet always keeping one bigger than the other to not violate the 2nd law. You cannot accept anything that Planck says without yourself judging if that is correct or not? Science is not parrot science where you simply repeat what is written in book or stated by some since long dead scientist.

Again: what additional law is required to mathematically model atmospheric radiative heat transfer, beyond the one-directional SB/Planck law we have agreed on? Is it two-way heat transfer? If so, what equation does that effectively bring into the mathematical model? Have you read my post about Schwarzschild's (unphysical) equations based on two-way transfer? If not, do that and give your view on the necessity of Schwarzschild's model. OK?

Gavin: Claes, I have already answered your question repeatedly. The additional physical law that is required is the Stefan-Boltzmann law of radiation: j* = sigma*T^4. For the reasons, see my previous answers.

Now please give a direct answer to my previous question, I repeat:

Plank writes:A body A at 100C emits toward a body B at 0C exactly the same amount of radiation as toward an equally large and similarly situated body B' at 1000C. The fact that the body A is cooled by B and heated by B' is due entirely to the fact that B is a weaker, B' a stronger emitter than A.

My one question for this comment is: Is any of the radiation emitted by B (at 0C) absorbed by A (at 100C), "yes" or "no"?

You earlier wrote:

To meet a question by a battery of counter-questions is a way to avoid answering the original question. I am sure you would not like to resort to this form of discussion trickery, right?

Note that in my previous comment I asked precisely one question (only one question mark), but in your reply, you did not give an answer, but you asked multiple questions (I count six question marks!).

Claes: My answer is no.

Gavin: Thank you, that is interesting. Consider a third body B'' at 50C, which is of a similar size to B and again similarly situated. I am assuming that since B'' is also cooler than A, you would say that no radiation from B'' is absorbed by A either. Feel free to correct me if this assumption is incorrect. My question is, does A emit a different amount of radiation towards B than it emits towards B''?

Claes: Radiative heat transfer between bodies is described by the one-directional SB law we have agreed is valid.

Gavin: That is not a direct answer to the question, A either does emit a different amount of energy towards B than it emits towards B'', or it does not. Which is it?

Claes: SB gives the answer to your question. This is an exercise you can do yourself. After all you are the teacher and should know.

Gavin: The reason that I am asking for an unequivocal answer is that I intend to demonstrate a contradiction and do not want to leave room for equivocation after it has been established. If you are confident of your position, you ought to be eager to state your position in completely unequivocal terms. So I ask again:

"does A emit a different amount of radiation towards B than it emits towards B''?"

"yes" or "no".

Claes: A as warmer transfers heat to B and B" according to SB. If B" is warmer than B, then less heat energy transfers from A to B" than to B.

Claes: You claim that in addition to SB in the form Q = sigma (T_A^4 - T_B^4) with T_A > T_B, you need an SB of the form Q = sigma T_A^4. But the latter is included in the former if you set T_B = 0. So why is the extra SB needed?

Claes: Gavin: While you are thinking, I hope you also remember to answer my original question about the meaning of the statement "although heat moves in all directions..." in a video of week 3.
Gavin: I have now asked ClaesJohnson a straight-forward "yes"/"no" question three times, and each time have recieved an evasive response. As I have already explained why an indirect answer would be indicative of evasion, I think it is reasonable to conclude that the evasion was deliberate.

ClaesJohnson subsequently attempted to divert the discussion away from a line of inquiry that will demonstrate a contradiction in his position by repeating a question from earlier in the discussion that has already been answered (repeatedly). Again this is evasion.

Socratic method (a form of enquiry based on asking and answering questions) is an excellent means of resolving scientific disagreements, provided that both parties engage in the exercise in good faith. This cross-examination allows misunderstandings to be resolved and exposes the weaknesses in either argument. Evading direct questions is a clear indication that someone is unwilling to change their views, regardless of the evidence or opposing arguments presented. In this case, there is little point in continuing the discussion, and the observers can draw their own conclusion from the evasion.

Ulimately, if ClaesJohnson refuses to look at anything other than the "one-direction" SB law for radiative heat transfer, and is unable to understand that this arises as the net result of a bi-directional transfer of energy (as illustrated by Planck's example), he will be unable to understand why the greenhouse effect doesn't violate the second law of thermodynamics. However, he can't say that this has not been explained to him.

Claes: Gavin, I think we have come to the end of our discussion. Yes, it is true that only the uni-directional SB makes sense to me and to physics. You have not been able to give any scientific support to a "greenhouse effect" based on two-directional heat transfer including "back radiation" with heat transfer from cold to warm, and neither have you been able to explain the obvious violation of the 2nd law in such a process. This means that a "greenhouse effect" based on "back radiation" is nonphysical illusion. The result is that the course lacks sufficient scientific basis and should be closed.

Gavin: ClaesJohnson If only the uni-directional SB makes sense to you, then perhaps you should not obstruct attempts to explain the bi-directional energy transfer required for an understanding of back radiation by the sort of evasive behaviour you have demonstrated during this discussion.

Claes: I have declared my standpoint very clearly. The evasiveness is yours. I am surprised that edX offers a platform for the kind of propagandistic disinformation the course presents. In any case the "denial" will not be affected by the course.