Corruption of Modern Physics 18: What is a Photon?

This is a continuation of Corruption of Modern Physics 1 as a celebration of the 2022 Nobel Prize in Physics to be delivered on Dec 10 by King Carl XVI Gustaf. 

I read in Electromagnetic fields, size, and copy of a single photon by Shan-Liang Liu:

• Light is almost involved in each field of science anddaily life of everyone, and yet light’s true nature has eluded us for centuries. 
• Albert Einstein successfully explained the photoelectric effect in 1905 by the assumption that light is composed of photons and showed that a photon has constant energy hν and momentum h/λ where h is the Planck constant, ν is the requency, and λ is the wavelength. 
• The theory of relativity tell us that a photon has zero rest mass and always moves at the speed of c=λν in vacuum.
• However, these answers are not satisfactory. Roy J. Glauber once jokingly summarized his theory of photo detection by the sentence: “I don’t know anything about photons, but I know one when I see one”.
• Single photons are essential for the fundamental study of the quantum mechanics and the development of photonic quantum technologies such as optical quantum computing and quantum communication
• However, there is not still a satisfactory answer to the problem what a photon is.
• Experiments have indicated that a single photon can locate in very small space and very short time duration  but how to know the size of a photon is till a puzzling question. 
• The wave-like properties of light or photons are well described by the classical theory of electromagnetic fields. 
• How to properly describe the electromagnetic fields of a single photon is still a fundamental and unresolved question in physics. 

So I get confirmation for my long held suspicion that physicists still today, in particular in the light of the Nobel Prize in Physics this year which was awarded to so called entangled photons, do not know what they are talking about when they are talking about photons. This is yet another example of the strangeness of modern physics.

Why You Cannot Heat Yourself by a Mirror

When now winter approaches and energy costs are sky-rocketing, you may find yourself desperately seeking means to survive from freezing to death and all possibilites must be tested. Right?

Here is one possibility which typically can be put forward by anyone who believes that all bodies including your own emit a stream of photons with total heat energy scaling with $T^4$ with $T$ absolute temperature according to the Planck-Stefan-Boltzmann Law PSB independent of the temperature of the surrounding. Although this is a misconception of PSB, which in true form also includes the temperature of the surrounding, it is commonly believed even by physicists to be a fact and as such may propose the following:

Put up mirrors around the walls of your living room, if this is where you plan to hide during the winter (Germany allows only one room to be heated), and say to yourself: All these photons that I emit will be reflected back to me from all the mirrors and so I will be heated as much as I am cooling. This is nothing but the so called "greenhouse effect" heating the Earth surface from "back radiation" from the atmosphere supposedly acting somewhat like a mirror sending back radiation from the surface. 

Before you go buying all these mirrors, let me tell you why this won't work by referring to the analysis presented on Computational BlackBody Radiation: This is because transfer of heat from one body A to another B only occurs when say A is warmer than B, and this is because then A emits radiation with higher frequencies than B and it is these higher frequencies that have a heating effect on B lacking these frequencies.  

It is the same as transfer of knowledge from one person who is more knowledgable to a person less knowledgable. In both cases a threshold effect comes into play with the threshold set by the less knowledgable/cooler body. This effect is not present if you think of radiation as a stream of photons where something very essential is missing.

To those who believe that radiative heat transfer involves a stream of photons back and forth between bodies, I suggest to go to buy the mirrors, make a test and report back to me. Good Luck! 

Or check out Computational BlackBody Radiation and save that effort. You will then understand why you cannot heat yourself by a mirror, or teach yourself all by yourself anything above your threshold, or lift yourself in the hair!

Phlogiston Theory vs Radiation Theory with Back Radiation

Phlogiston theory and radiation theory with "back radiation" shares a common theme: Both describe  phenomena taking place as if in a vacuum, without input from the actual environment:

Phlogiston theory states that a phlogistated substance burns by consumption of phlogistons (or "fire elements") inside the substance in a process of dephlogistication without input from the environment, as if taking place in a vacuum. 

Radiation theory with back radiation states that all bodies of modest temperatures radiate infrared photons (or "light elements") out of the body independent of the temperature of the surrounding environment, as if taking place in a vacuum.  

Phlogistons have never been identified and observed, and neither have infrared photons. Both are elements believed to be hiding inside a substance capable of escaping into a surrounding vacuum.

For an earlier post on phlogistons and infrared photons, see here.

PS You can buy an infrared detector like an infrared camera reacting to infrared light. Is an infrared camera a collector of infrared photons, like a butterfly net collecting butterflies flying through the air?

No. A cooled infrared camera absorbs heat energy from a warmer object and an uncooled infrared camera emits heat energy to a cooler object. In neither case does the camera collect a nominal flow of "light elements" supposedly being emitted by an object into a surrounding vacuum. Compare with previous posts under category "infrared thermometer".

You can use your on body as detector of a colder or warmer environment than your skin, by noticing a feeling of being cooled or heated, but your perceived sensation is not evidence of  "infrared photons" flying in and out of your body.

Why the Same Universal Quantum of Action $h$ in Radiation, Photoelectricity and Quantum Mechanics?

Planck's constant $h$ as The Universal Quantum of Action was introduced by Planck in 1900 as a mathematical statistical trick to supply the classical Rayleigh-Jeans radiation law $I(\nu ,T)=\gamma T\nu^2$ with a high-frequency cut-off factor $\theta (\nu ,T)$ to make it fit with observations including Wien's displacement law, where

• $\theta (\nu ,T) =\frac{\alpha}{\exp(\alpha )-1}$,
• $\alpha =\frac{h\nu}{kT}$, 

$\nu$ is frequency, $T$ temperature in Kelvin $K$ and $k =1.38066\times 10^{-23}\, J/K$ is Boltzmann's constant and $\gamma =\frac{2k}{c}$ with $c\, m/s$ the speed of light in vaccum. Planck then determined $h$ from experimental radiation spectra to have a value of $6.55\times 10^{-34} Js$, as well as Boltzmann's constant to be $1.346\times 10^{-23}\, J/K$ with $\frac{h}{k}= 4.87\times 10^{-11}\, Ks$ as the effective parameter in the cut-off.  

Planck viewed $h$ as a fictional mathematical quantity without real physical meaning, with $h\nu$ a fictional mathematical quantity as a smallest packet of energy of a wave of frequency $\nu$, but in 1905 the young ambitious Einstein suggested an energy balance for photoelectricity of the form 

• $h\nu = W + E$,

with $W$ the energy required to release one electron from a metallic surface and E the energy of a released electron with $h\nu$ interpreted as the energy of a light photon of frequency $\nu$ as a discrete lump of energy. Since the left hand side $h\nu$ in this law of photoelectricity was determined by the value of $h$ in Planck's radiation law, a new energy measure for electrons of electronvolt was defined by the relation $W + E =h\nu$. As if by magic the same Universal Quantum of Action $h$ then appeared to serve a fundamental role in both radiation and photoelectricity.

What a wonderful magical coincidence that the energy of a light photon of frequency $\nu$ showed to be exactly $h\nu \, Joule$! In one shot Planck's fictional smallest quanta of energy $h\nu$ in the hands of the young ambitious Einstein had been turned into a reality as the energy of a light photon of frequency $h\nu$, and of course because a photon carries a definite packet of energy a photon must be real. Voila!

In 1926 Planck's constant $h$ showed up again in a new context, now in Schrödinger's equation

• $-\frac{\bar h^2}{2m}\Delta\psi = E\psi$

 with the formal connection   

• $p = -i\bar h \nabla$ with $\bar h =\frac{h}{2\pi}$,
• $\frac{\vert p\vert^2}{2m} = E$, 

as a formal analog of the classical expression of kinetic energy $\frac{\vert p\vert ^2}{2m}$ with $p=mv$ momentum, $m$ mass and $v$ velocity.

Planck's constant $h$ originally determined to make theory fit with observations of radiation spectra and then by Planck in 1900 canonized as The Universal Quantum of Action, thus in 1905 served to attribute the energy $h\nu$ to the new fictional formal quantity of a photon of frequency $\nu$ . In 1926 a similar formal connection was made in the formulation of Schrödinger's wave equation.  

The result is that the same Universal Quantum of Action $h$ by all modern physicists is claimed to play a fundamental role in both (i) radiation, (ii) photolelectricity and (iii) quantum mechanics of the atom. This is taken as an expression of a deep mystical one-ness of physics which only physicists can grasp,  while it in fact it is a play with definitions without mystery, where $h$ appears as a parameter in a high-frequency cut-off factor in Planck's Law, or rather in the combination $\hat h =\frac{h}{k}$,  and then is transferred into (ii) and (iii) by definition.  Universality can this way be created by human hands by definition. The power of thinking has no limitations, or cut-off.

No wonder that Schrödinger had lifelong interest in the Vedanta philosophy of Hinduism "played out on one universal consciousness".

But Einstein's invention of the photon as light quanta in 1905 haunted him through life and approaching the end in 1954, he confessed:

• All these fifty 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. 

Real physics always shows up to be more interesting than fictional physics, cf. Dr Faustus ofd Modern Physics.

PS Planck's constant $h$ is usually measured by (ii) and is then transferred to (i) and (iii) by ad hoc definition.

Blackbody Radiation as Collective Vibration Synchronized by Resonance

There are two descriptions of the basic phenomenon of a radiation from a heated body (blackbody or greybody radiation) starting from a description of light as a stream of light particles named photons or as electromagnetic waves.

That the particle description of light is both primitive and unphysical was well understood before Einstein in 1905 suggested an explanation of the photoelectric effect based on light as a stream of particles later named photons, stimulated by Planck's derivation of Planck's law in 1900 based on radiation emitted in discrete quanta. However, with the development of quantum mechanics as a description of atomistic physics in the 1920s, the primitive and unphysical idea of light as a stream of particles was turned into a trademark of modern physics of highest insight.

The standpoint today is that light is both particle and wave, and the physicist is free to choose the description which best serves a given problem. In particular, the particle description is supposed to serve well to explain the physics of both blackbody radiation and photoelectricity. But since the particle description is primitive and unphysical, there must be something fishy about the idea that emission of radiation from a heated body results from emission of individual photons from individual atoms together forming a stream of photons leaving the body. We will return to the primitivism of this view after a study of the more educated idea of light as an (electromagnetic) wave phenomenon.

This more educated view is presented on Computational Blackbody Radiation with the following basic message:

1. Radiation is a collective phenomenon generated from in-phase oscillations of atoms in a structured web of atoms synchronized by resonance.
2. A radiating web of atoms acts like a system of tuning forks which tend to vibrate in phase as a result of resonance by acoustic waves. A radiating web of atoms acts like a swarm of cikadas singing in phase. 
3. A radiating body has a high-frequency cut-off scaling with temperature of the form $\nu > \frac{T}{\hat h}$ with $\hat h = 4.8 \times 10^{-11}\, Ks$,where $\nu$ is frequency and $T$ temperature in degree Kelvin $K$, which translates to a wave-length $\lambda < \hat h\frac{c}{T}\, m$ as smallest correlation length for synchronization, where $c\, m/s$ is the speed of light. For $T =1500 K$ we get $\lambda \approx 10^{-5}\ m$ which is about 20 times the wave length of visible light.   

We can now understand that the particle view is primitive because it is unable to explain that the outgoing radiation consists of electromagnetic waves which are in-phase. If single atoms are emitting single photons there is no mechanism ensuring that corresponding particles/waves are in-phase, and so a most essential element is missing.

The analysis of Computational Blackbody Radiation shows that an ideal blackbody is characterized as a body which is (i) not reflecting and (ii) has a maximal high frequency cut-off. It is observed that the emission from a hole in a cavity with graphite walls is a realization of a blackbody. This fact can be understood as an effect of the regular surface structure of graphite supporting collective atom oscillations synchronized by resonance on an atomic surface web of smallest mesh size $\sim 10^{-9}$.

 

Physics Illusion 12: Modern vs Classical World

Leibniz develops a solution of the mind-body problem arising from the dualism of Descartes as an analogy to the well known physical phenomenon of resonance between two pendula or tuning forks swinging in perfect harmony together:

Leibniz World is a world in such perfect harmony, and as such a Best of Worlds, with everything in resonance with everything else as an expression of Pre-established Perfect Harmony without cause-effect.

Another example is a coldblooded animal with temperature in perfect harmony with that of the environment, again by a resonance phenomenon as analyzed in Computational Black Body Radiation:

Leibniz World is a Classical World in stationary state of resonance with forces in equilibrium, to be compared with a Modern World in rapid change from non-equilibrium of forces.

In a Classical World in a stationary state of resonance, a distinction between cause and effect cannot be made because the directional aspect of time, with a cause necessarily appearing before an effect, is missing. An example is the Newton's law of gravitation $\rho =\Delta\phi$ between mass density $\rho$ and gravitational potential $\phi$, possibly without cause-effect or in any case not with $\rho$ the cause and $\phi$ the effect, as discussed at length in the present sequence of posts.

In a Modern World changing in time the cause-effect relation is of basic importance, in particular for anyone with ambitions to exercise control and there are many. In a Modern World with the physics of control becomes of paramount importance, and then the basic idea of modern physics of force carrying particles comes in handy:

• If you want to control something far away, just send some force carrying particles, like rockets or drones and you will be able to complete your mission.
• A hot body is sending heat energy carrying particles named photons to warm up a cold body.
• Gravitational forces between bodies are established by exchange of force carrying particles named gravitons.
• Electromagnetic forces are transmitted by force carrying particles named photons.
• Strong and weak nuclear forces are transmitted by force carrying particles named gluons and W/Z-bosons. 

While there are rockets and drones, the physical existence of particles like photons and gravitons may be more fiction than reality.

Ambitions of control may be huge, while reality of control is another thing. The cause-effect relation may not be want you would like it to be.

Below is a modern physics view of a world filled with force carrying particles:

Modernity is change and cause-effect action expressed as Will to Power by Nietzsche and in the dynamics of a capitalistic system, in contrast to a classical society in equilibrium. But sociology and politics is not physics, and so the modernity of modern physics may be illusion more than reality.

The revolution into modern physics the beginning of the 20th century (relativity and quantum mecahnics) came along with a revolution of technology (car, telephone, electricity, oil) combined with revolutions in politics, art, music, where old systems were overthrown with radical novelty of top priority. But physics is eternal and does not care about novelty, and so a lot of relevant classical physics (Newtonian mechanics and Maxwellian electromagnetics) was dumped in modern physics.

Modernity as motion was expressed in the avant-garde art movement of futurism:

                                    Unique Forms of Continuity in Space, by Umberto Boccioni (1913).

Physics Illusion 2: Photons as Light Particles

Computational Blackbody Radiation describes radiative energy transfer as a resonance phenomenon between resonators connected by standing electromagnetic waves in a vacuum between the resonators. The acoustic analog is depicted above: Energy is transferred from one tuning fork to another by standing acoustic waves as pressure variations in still air.

In this model the finite speed of electromagnetic (or acoustic) waves only influences the energy transfer in a start up phase, while in a stationary state of standing waves the energy transfer can be viewed to be instantaneous without time delay, or to be without time aspect. The transfer of energy is one-way from hot (high frequency) to cold (low frequency).

In this view there is no need to introduce particles named photons carrying energy packets at finite speed back and forth between the resonators, as if the resonators were connected by a two-way highway with trucks transporting energy in both directions. There is no experimental evidence of the existence of such a two-way stream of light quanta. Einstein introduced light quanta in his annus mirablis 1905, but changed mind before passing away:

• All these fifty 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. (Albert Einstein, 1954)

The lights we see in the sky thus result from resonance by standing electromagnetic waves in the vacuum between our eyes and a distant star, and not by light particles having traveled for billions of years before hitting the retina of an eye. Energy is transferred from one tuning fork to the other by acoustic standing waves but there are no phonon particles carrying the energy by flying like a swarm of wasps between the forks.

The idea of a photon as an elementary particle acting as force carrier of the electromagnetic force, is a basic element of the standard model. No wonder that physicists are not happy with this model. The photon as carrier of the electromagnetic force like the graviton as carrier of the gravitational force, is probably Einstein's biggest mistake, far bigger than the cosmological fudge constant in Einstein's equations, and a return to the primitive corpuscular theory of light of Thomas Hobbes (1644), which was superseeded by Huygen's wave theory (1678), once Newton was dead, but then surprisingly popped up again in Einstein's 1905 article on the photoelectric effect.    

IR-Photons as Optical Phonons as Waves

In climate science it is common to view radiative heat transfer as a two-way flow of IR-photons particles carrying lumps of energy back and forth between e.g. the Earth surface and the atmosphere.

This view lacks physics rationale because it includes heat transfer by IR-photons not only from warm to cold, but also form cold to warm in violation of the 2nd Law of Thermodynamics. The usual way to handle this contradiction is to say that the net transfer is from warm to cold, and so there is no violation of the 2nd Law. But this requires the two-way transfer to be connected which is in conflict with an idea  independent two-way transfer.

On Computational Blackbody Radiation I present a model of radiative heat transfer which is based on a wave equation for a collection of oscillators with small damping subject to periodic forcing solved by finite precision computation. Fourier analysis show that the oscillators in resonance take on a periodic motion which is out-of-phase with the forcing, which connects to optical phonons as wave motion in an elastic lattice with large amplitude (as compared to acoustical phonons with smaller amplitude).

Optical phonons typically occur in a lattice composed of two atoms of different mass, one big and one small, which connects to the radiation wave model with small damping.

We thus find reason to view IR-photons as a wave phenomenon similar optical phonons, rather than as "particles".

The radiation wave model includes two-way propagation of waves but only one way transfer of heat energy as an effect of cut-off of high frequencies due to finite precision computation.

IR Photons as Phlogistons

A photon is as elementary particle the carrier of the electromagnetic force. 

A phonon is as collective elastic excitation in a lattice of atom or molecules the carrier of sound, referred to as a "quasiparticle". 

A phonon is a collective sound wave while a photon is a "light particle". In a previous post I considered  an acoustic model of radiative heat transfer between the Earth surface and the atmosphere and outer space, in the form of a string instrument with energy transfer from string to soundboard to surrounding air.

It is common to describe infrared radiative heat transfer between two bodies as a two-way flow of IR photon particles carrying "energy quanta" back and forth between the bodies. I have argued that this view is non-physical in the sense that energy is supposed to be carried not only from warm to cold, but also from cold to warm which is in violation of the 2nd law of thermodynamics. 

To understand that the particle view is non-physical, it is illuminating to consider a model of the string instrument where the concept of phonon wave is replaced by "phonon particle" as an acoustic counterpart to a photon particle. A "phonon particle" would thus be a form of elementary particle as "sound particle" and "carrier of sound (force)".  

We would then view the sound produced by the string instrument as consisting of a two-way flow of phonons between string and soundboard and between soundboard and surrounding air. In this model the sound of the surrounding air would send phonons to the soundboard which would send phonons to the string. This would be in violation with our experience reflecting the 2nd law, that it is the string which makes the soundboard vibrate, which makes the sound wave in the air. 

We understand that a phonon particle model of a string instrument is non-physical as violation of the 2nd law and thus misleading.

In the same way an IR photon particle model of infrared radiative heat transfer is non-physical as violation of the 2nd law and thus misleading. Yet this model underlies the idea of "backradiation" from the cold atmosphere the to warmer Earth surface, which is a central part of CO2 alarmism.
  

Such a photon theory postulating heat transfer by photon particles without mass, charge, color, odor or taste, can be compared with the phlogiston theory postulating that in all flammable materials there is present phlogiston, a substance without color, odor, taste, or weight that is given off in burning.

Notice that because of the long wave length of infrared radiation, and IR-photon is similar to a phonon and thus is better described as collective wave phenomenon than as discrete particle. Compare with previous post on the subject.

PS There is a connection between optical phonons as large amplitude out-of-phase wave vibration of a lattice of two different atoms with different mass (as compared to acoustic small amplitude in-phase vibration), and the analysis of blackbody radiation on Computational Blackbody Radiation with incoming and outgoing radiation out-of-phase (also characteristic of a string instrument designed to give large amplitude output).

Radiative Heat Transfer: Phlogistons and Photons

I will now argue that phlogiston theory has similarities with photon theory of light in the case of infrared radiation of global climate.

Phlogiston theory says that all combustible resources contain particles named phlogistons without colour, odor, taste or mass, which are liberated in burning.

Photon theory says that light consists of particles named photons without mass and charge carrying energy along straight lines at a constant speed of light. Photons have different frequencies and and energy proportional to frequency.

Photon theory describes radiative heat transfer between two bodies as a two-way stream of photons emitted/absorbed by the bodies, with the hotter body emitting photons of higher frequency and in higher numbers as compared to the colder body, which results in a net transfer of heat energy from hot to cold.

Photon theory is a particle theory of light going back to Newton's corpuscular theory of light,

and is to be compared with the wave theory of light as electromagnetic waves described by Maxwell's equations. The wave theory of light describes almost all observed phenomena of light.

The wave theory of light replaced the particle theory in the late 19th century, but was revived in the early 20th century by Planck to describe blackbody radiation and by Einstein to describe the photoelectric effect.

Phlogiston theory is no longer taught, but the photon theory of light is still used to explain certain phenomena believed to be difficult to explain by a wave model, typically related to the

phenomena of emission and absorption involving interaction between matter and electromagnetic waves. In photon theory emission is seen as ejection of photon particles and

absorption as the opposite.

For visible light, emission of photons as finite quanta of energy can be associated with discrete changes of atomic electronic structure. For infrared radiation with much larger wave lengths than atomic dimensions, the interaction between matter and waves must involve collective motion of many atoms and the photon theory does not seem to be applicable.

This mean that photon theory cannot be used to describe blackbody radiation at the modest temperatures of global climate. In this case the photon theory is similar to the phlogiston theory as a very simplistic theory with little predictive capability, and a wave theory based on Maxwell's equations can be preferable, as shown in Mathematical Physics of Blackbody Radiation.

The fact that photon theory can be useful for certain applications at high-energy short wave-lenghts, does not mean that it is also uselful for completely different applications at low-energy long wave-lengths.

Nevertheless, the photon theory serves as support of the propaganda of CO2 alarm based on

the idea that streams of photons from the atmosphere contribute to global warming as DLR/backradiation, which rather represents phlogiston theory than real physics.

Pushing a Swing: Essence of Blackbody Radiation

Satyr pushing a Nymph on a swing as part of the Dionysian cult.

The essence of blackbody radiation can be understood from a model of a swing containing the elements of

1. swing or oscillator
2. resistance (radiative or viscous dissipation)
3. forcing (exterior force)

from the following balance of forces:

• swing force + resistive force = forcing.

The essence connects to the interaction of the forcing with the swing, more precisely if the forcing is (i) in-phase with with the swing velocity or (ii) out-of-phase with the swing velocity.

In case (i) the swing is pushed by the exterior force when moving in the direction of the force. The force thus changes direction at the extreme positions of the swing.

In case (ii) the phase is shifted by a quarter of a period so that the force changes direction when the swing is in its bottom position.

The interaction between the swing and the forcing according to (i) or (ii) is determined by the size of the resistive force:

• large resistive force gives (i) with little interaction between swing and forcing; exterior force balanced mainly by resistive force,
• small resistive force gives (ii) with possible interaction between swing and forcing; exterior force balanced mainly by swing force.

The catch is now that in blackbody radiation the resistive force is small which means that

there is an interaction between the swing and the forcing as in (ii): Under increasing forcing the amplitude of the swing increases until the energy of the radiation balances the energy of the forcing, with the swing acting as reservoir of (heat) energy.

In other words, under increasing forcing a blackbody heats up until the radiance balances the energy of the forcing.

The interaction between the swing and the forcing can be turned around so that the resistance acts as input forcing and the exterior forcing is considered as the outgoing forcing with the swing acting as an amplifying resonance board allowing considerable output under small resistive forcing (from the strings of a piano or guitar).

In this perspective, there is a cut-off of high frequencies in outgoing forcing, which can be understood as an inability of the resonance board to amplify sufficiently high frequencies.

The mathematics of the above scenario of blackbody radiation is presented in my Sky Dragon article Computational Blackbody Radiation. Also recall Piano as Blackbody.

The basic idea is to understand blackbody radiation in an educated way as a wave mechanics phenomena and not in a primitive way as a particle mechanics phenomenon of massless photons streaming in an out.

A blackbody in equilibrium with some forcing radiates what is absorbed. What is then the distinction from reflection which also sends out whatever comes in?

Yes, you are right: In reflection there is no swing acting as a recervoir of heat energy, which can change under changing forcing:

• A blackbody absorbs the incoming waves into its interior (into the swing) before radiating out what is not stored in its interior recervoir.
• A reflecting body simply sends back what comes in without changing its interior state.
• A blackbody thus represents real interaction between matter and light/radiation (electromagnetic waves), while in reflection there is no such interaction.

The beauty of many blackbodies interacting by radiation, as opposed to many bodies interacting by reflection, is that the internal states of the blackbodies become harmonized to the same common temperature, while the reflecting bodies keep their initial temperatures.

You may compare with the following student reactions to teaching:

1. The student understands, absorbs and re-emits what the teacher says.
2. The student does not understand anything, absorbs nothing and only repeats like a parrot what the teacher says.

It is clear that 1. is more interesting than 2., that blackbody absorption/emission is more interesting than reflection.

Are There Any Photons At All?

The idea of light as a stream of particles or photons has been questioned and still is:

• Lamb: Only a comedy of errors and historical accidents led to its popularity among physicists and optical scientists.
• Moret-Bailly: Quantum electrodynamics corrects miscalculations of classical electrodynamics, but by introducing the pseudo-particle "photon" it is the source of errors whose practical consequences are serious.
• Xavier-Borg: "All these fifty 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" (Einstein, 1951). Sixty more years have passed, theories have been revised and updated, new technologies have surfaced, and yet it seems that nobody has had the guts to tackle this challenging issue again. Scientists seem satisfied enough reciting the wave-particle duality.

In Mathematical Physics of Blackbody Radiation I analyse a wave model of radiation and derive Planck's law from a principle of finite precision computation as an alternative to Planck's original derivation based on particles or quanta.

The basic idea is that atomic or molecular vibrations of a radiating body must be coordinated to deliver a coherent signal, like a swarm of crickets oscillating in unison, and that the required coordination requires a certain temperature to be effective.

Radiation is in this perspective an emergent phenomenon resulting from coordinated in-phase oscillations by many atomic oscillators , and not as in a particle model the result of photons emitted by particles without phase coordination. '

Recall that many out-of-phase oscillators cancel each other and emit nothing.

The primitivism of the particle model of radiation as streams of photons, has made it very popular, but there is little scientific evidence that it describes physics better than phlogistons.

There is no reason that all observed phenomena of radiation including absorption, emission and transmission cannot be explained from wave mechanics without particles. This was the view of Schrödinger and the late Einstein.

See also the previous post: Light: Waves of Particles?

Are There Photons of Infrared Radiation?

In the discussion on Planetary Energy Budget on Climate Etc. Eli Rabbet makes the observation:

• The wavelength of IR light from the surface ranges from about 5 microns to about 50 microns. The space between molecules at atmospheric pressure is about a tenth of a micron. The size of a molecule is about .0002 microns.

I respond by

• To explain IR by photons does not make sense. If you read my treatise on blackbody radiation or my Sky Dragon article, then you will find IR as a collective wave phenomenon involving many atoms which may give a better picture of the physics than mysterious giant photons being captured by miniscule atoms.

The idea of blackbody radiation as a collective phenomenon is also presented in the blog post

Blackbody Radiation as a Generic Emergent Phenomenon. In this perspective absorption and emission of IR cannot be explained by looking at properties of single atoms or molecules, but results from the interaction of many atoms.

The energy of IR radiation seems to be too small to result from electronic transitions.

The radiative properties of the atmosphere may thus not be explainable solely in terms of so-called greenhouse gases with specific atomic absorption/emission spectra.

The idea of photon particles as carriers of heat energy is primitive, confusing and has led to the unphysical concept of back radiation. Radiation as wave phenomenon makes much better sense.

Light: Waves or Particles?

Is light electromagnetic waves described by Maxwell's equations, or a stream of "light particles" or "photons" as described by Newton? Is heat transfer by radiation an electromagnetic wave phenomenon, or is it a stream of small packets/particles of "energy quanta"?

This is a basic question in physics and also of climate science since our climate is a thermodynamic heat engine powered by radiation from the Sun in the visible spectrum, and cooled by infrared radiation to outer space, with the Earth absorbing high-frequency light and emitting low-frequency light like a blackbody.

Until 1900, the answer was clear: Maxwell's equations was a wonderful gift to humanity as an amazingly compact yet complete description of light and propagation of light, from scientific

point vastly superior to the primitive particle idea of Newton. Educated people would say waves and not particles.

But there was a problem: The phenomenon of blackbody radiation when approached with wave mechanics led to an "ultraviolet catastrophy" with infinite radiated energy in direct contradiction with observation. To save physics from catastrophy something had to be done and it was Max Planck who took on the responsibility, as the successor of the great Kirchhoff at the University of Berlin and a very ambitious member of the newly formed German Physical Society aimed at giving The Kingdom of Prussia a leading role in the scientific world.

After much agony Planck in 1900 gave in and sacrificed rational deterministic wave mechanics, replacing it with irrational statistics of "energy quanta" described by himself as:

• 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...

And so modern physics was born with the catastrophy elegantly handled by a Salomonic:

• light is both waves and particles, sometimes this sometimes that, and you are free to chose whatever suits you the best, also referred to as wave-particle duality.
  

In 1905 the young Einstein used Planck's energy quanta to explain the photoelectric effect,

which added to the success of the revival of Newton's primitive particle theory, requiring wave-particle duality because after all the full particle primitivism of Newton was untenable. But also wave-particle duality is a form of scientific primitivism: Of course you can as a reasonable human being sometimes act like a fool, but duality is here called schizophrenia, and schizophrenic science is crazy science, in our time represented by CO2 climate alarmism ultimately based on radiation as particles.

Both Planck and Einstein struggled to pay the price of introducing particles all through their lives with the logical tragical end:

'

• All these fifty 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. (Einstein shortly before his death 1954)
• I consider it quite possible that physics cannot be based on the field concept, i.e., on continuous structures. In that case, nothing remains of my entire castle in the air, gravitation theory included, and of the rest of physics. (Einstein 1954)
• What wanted to say was just this: In the present circumstances the only profession I would choose would be one where earning a living had nothing to do with the search for knowledge. (Einstein's last letter to Born Jan 17 1955 shortly before his death on the 18th of April, probably referring to Born's statistical interpretation of quantum mechanics).
• Would it not be possible to replace the hypothesis of light quanta by another assumption that would also fit the known phenomena? If it is necessary to modify the elements of the theory, would it not be possible to retain at least the equations for the propagation of radiation and conceive only the elementary processes of emission and absorption differently than they have been until now? (Einstein)
• We shall now derive strange properties of heat radiation described by electromagnetic wave theory. (Planck 1900)
• We shall assume that the radiation in one direction is completely independent of the radiation in a different direction, even opposite. (Planck)
• Either the quantum of action was a fictional quantity,then the whole deduction of the radiation law was essentially an illusion representing only an empty play on formulas of no significance, or the derivation of the radiation law was based on sound physical conception...Mechanically, the task seems impossible, and we will justhave to get used to it (quanta) (Planck 1909).
• Zur radikalsten Affassung neigt J.J Thompson und A. Einstein, welche glauben, das die Fortpflanzung der elektromagnetischen Wellen nicht genau nach den Maxwellshen Feldgleichungen, sondern nach gewissen Energiequanten h nu erfolgt. Ich meine dagegen, dass man einstweilen noch nicht genötig ist, so revolutionär vorzugehen, sondern das mann damit auskommen durfte, die Bedeutung des Energiequantums h nu lediglich in den Wechselwirkungen zu suchen, mit denen die Resonatoren einander beeinflussen. Eine definitive Entscheidigung uber diese prinzipiellen Fragen können aber erst weiter Erfahrungen bringen. (Planck 1908)
• Despite the great success that the atomic theory has so far enyoyed, utimately it will have tobe abandoned in favor of the assumption of continuous matter (wave mechanics) (Planck 1882).
• We therefore regard - and this is the most essential point of the entire calculation - energy to be composed of a very definite number of equal packages (Planck 1900).
• The wave theory of light, which operates with continuous spatial functions, has worked well in the representation of purely optical phenomena and will probably never be replaced by another theory (Einstein).
• I do not seek the meaning of “quantum of action” (light quantum) in the vacuum but at the site of absorption and emission (Planck 1907).
• Despite the apparently complete success of the Einstein equation (for the photoelectric effect), the physical theory on which it was designed to be the symbolic expression, is found so untenable that Einstein himself, I believe, no longer holds to it (Millikan).
• My futile attempts to fit the elementary quantum of action into classical theory continued for a number of years and cost me a great deal of effort. Many of my collegues saw in this something bordering on a tragedy (Planck shortly before his death).
• Einstein is increasingly aloof and sceptical (about the quantum discoveries he pioneered). Many of us regards this as a tragedy (Born).

These confessions viewed as deep insights rather than simply expressions of senility, give a pretty grim outlook on "present circumstances" of modern physics, including climate science...What if Einstein and Planck were right?

In Computational Blackbody Radiation I present a way of turning the tragedy into a happy end

by keeping wave mechanics, according to Planck's and Einstein's innermost dream, only

making it more realistic by including an aspect of finite precision computation, instead of resorting to ad hoc particle statistics, which the scientific souls of Planck and Einstein could never accept.