# Why Planck's Formula For Black Body Radiation Is Used To Measure The Cbr?

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### #1 rhertz

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Posted 23 April 2019 - 09:39 PM

The formula that Planck presented on December 14, 1900, to the German Physics Society (date celebrated as the birthday of Quantum Physics) is the final answer to the Kirchoff's 1859 challenge to the physics community: to find the spectral formula for his relationship between emissivity e(L) = J(L, T), with absorptivity a(L) being equal to one in a perfect black body cavity. I use L as Lambda (wavelength).

Edited by rhertz, 18 June 2019 - 08:02 PM.

### #2 Dubbelosix

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Posted 24 April 2019 - 03:22 AM

There's a lot of complicated issues, but really, to describe it in the simplest sense, Planck's law is universal. We apply it to black body's of all types.

### #3 Flummoxed

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Posted 24 April 2019 - 06:36 AM

I might be having a senior person day, but plancks constants is based on the hypothesis light has frequency like maxwells equations for radio waves. This is not necessarily the case for photons.  A photon of Light is a packet of energy with inertia, it causes a fluctuation in a field as it moves through space, it has no electric charge or magnetic field, it can be polarized ie it has spin 1. This is not an oscillatiing wave with frequency. The idealized picture a photon that goes in exactly in straight lines through space, with mystical properties of wave particle duality is likely a misunderstanding on how photons moves.

There is no way of measuring photons without interfering with them. The way in which it is measured affects the results. All we can really say is it leaves point A and arrives at point B. It is not affected by electric charges or magnetic fields, both of which are ascribed to virtual photons under qed.

Example throw an invisible particle into a pool and you will observe ripples, throw the same particle into sand, and you will observe a hole caused by a particles.

Red Shift indicates a reduction in energy of the photons received, which is analogous to the doppler effect, but it could equally be a tired light effect. Photons losing energy due to loss of momentum instead of by increased wavelength. Would be both measured in the same way, ie its a photon which just arrived at point B with an amount of energy.

Ascribing the doppler effect to red shift might be an incorrect assumption ?

Oh the final question WHY it was maybe the ultraviolet catastrophe. https://en.wikipedia...let_catastrophe that the mathematical jiggery pokery of planck resolved.

### #4 Dubbelosix

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Posted 24 April 2019 - 09:11 AM

But why protest which works in even an approximate sense? Science isn't always about being absolute, but it a lot of it has to do with equations which best fit ..... Unless of course an equation can manifest better answers.

### #5 Dubbelosix

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Posted 24 April 2019 - 10:46 AM

I might be having a senior person day, but plancks constants is based on the hypothesis light has frequency like maxwells equations for radio waves. This is not necessarily the case for photons.  A photon of Light is a packet of energy with inertia, it causes a fluctuation in a field as it moves through space, it has no electric charge or magnetic field, it can be polarized ie it has spin 1. This is not an oscillatiing wave with frequency. The idealized picture a photon that goes in exactly in straight lines through space, with mystical properties of wave particle duality is likely a misunderstanding on how photons moves.

There is no way of measuring photons without interfering with them. The way in which it is measured affects the results. All we can really say is it leaves point A and arrives at point B. It is not affected by electric charges or magnetic fields, both of which are ascribed to virtual photons under qed.

Example throw an invisible particle into a pool and you will observe ripples, throw the same particle into sand, and you will observe a hole caused by a particles.

Red Shift indicates a reduction in energy of the photons received, which is analogous to the doppler effect, but it could equally be a tired light effect. Photons losing energy due to loss of momentum instead of by increased wavelength. Would be both measured in the same way, ie its a photon which just arrived at point B with an amount of energy.

Ascribing the doppler effect to red shift might be an incorrect assumption ?

Oh the final question WHY it was maybe the ultraviolet catastrophe. https://en.wikipedia...let_catastrophe that the mathematical jiggery pokery of planck resolved.

By far you are the biggest thinker here, and you are able to collect idea's coherently, maybe not always right, but If I had taken a student on, you'd be the type I'd take on.I'll try and get back to all these posts, but you ask many complicated questions which require... a push in the right direction.

### #6 Flummoxed

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Posted 25 April 2019 - 03:36 PM

By far you are the biggest thinker here, and you are able to collect idea's coherently, maybe not always right, but If I had taken a student on, you'd be the type I'd take on.I'll try and get back to all these posts, but you ask many complicated questions which require... a push in the right direction.

My wife might disagree, she thinks I am always right:) (normally) .

I am open to being educated, can you tell me what is wrong with what I wrote above.

The transition, for the physics community, between the generalized concept of electromagnetic waves toward an acceptance

of the discretness of energy and the existance of "photons" took more than 15 years, and yet not everyone was convinced

about the model of the atom and quantum jumps to absorb or emit energy by electrons.

By 1930, it was adopted that light had a DUAL NATURE: As a wave, to propagate, difract, reflex or passthrough materials and as

a particle, when emission or absorption of energy by atoms was involved.

Using this dual nature has led to several paradoxes, like the "slit experiment", but it is what happens today.

I think that, someday, someone will find a better theory for light that may unifiy both behaviors as the dual nature of light is

somewhat a "crazy concept".

Red-shifting applies to waves, as well as Doppler effect.

Plancks created a turning point in the history of physics, because his introduction of the minimal possible value that electromagnetic energy can have, being multiples of his hʋ minimal value of energy for an EM wave at the frequency ʋ. This point was an irreversible path away from the analog newtonian physics, with his possibilities of infinitesimally small values of electromagnetic energy.

How does Planck arrive at the conclusion light has frequency.

I think red shifting would also apply to tired light as suggested by Zwicky.

Bohm suggested pilot waves to explain the double slit experiment, and to do away with wave particle duality, which is kind of plausible, the field of the photon interacts with both slits before the photon passes through one slit or the other.

Looking directly at what we KNOW about photons, not what we assume. Light bends around sharp corners, laser beams diverge as they pass through air, likely through interaction with air molecules, they also diverge in space, due to what? quantum foam interactions. This would imply the trajectory of a photon is not in a straight line, and might be better modeled as a probability wave. ie its getting knocked around, less so if it has higher energies which would result in narrower spacing of lines in the double slit experiment. Additionally the photons leaving the emitter are likely not leaving from the same location +/- a few microns. The idealized double slit experiment seems like it is intended to prove a wave feature to photons when there is likely none.

Plancks created a turning point in the history of physics, because his introduction of the minimal possible value that electromagnetic energy can have, being multiples of his hʋ minimal value of energy for an EM wave at the frequency ʋ. This point was an irreversible path away from the analog newtonian physics, with his possibilities of infinitesimally small values of electromagnetic energy.

How does Planck arrive at the conclusion light has frequency.

Edited by Flummoxed, 25 April 2019 - 03:38 PM.

### #7 Flummoxed

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Posted 26 April 2019 - 03:30 AM

He didn't. Maxwell did when he introduced the Theory of Electromagnetism in 1865. You can find the original paper if you search enough, It worth it,

Maxwell studied light nature and effect on human vision as an obsession since he was a child. After gaining his PhD, he worked in theory of color (where

he made practical contributions to medicine that made him famous worldwide, like discovering color blindness), on kinetic theory of perfect gases (and also

creating - along with Boltzmann 10 years after - the field of statistical mechanics), on astronomy (solving the nature of Saturn's rings, what again made him

famous), on electricity and magnetism (he created his monumental Treatise, 700+ pages, with the whole knowledge existing by then). But his most famous

theory, which has been unchallenged for 150 years, was the creation of the science of electromagnetism. In 1865, he published his theory, which had to

wait more than 50 years to be fully appreciated, where he PROVED the electromagnetic nature of thermal radiation and, by extension, he assimilated light

to this kind of behavior. Maxwell proposed the current model of an electromagnetic wave of ANY FREQUENCY, even that of the light, composed by self-sustaining alternating orthogonal fields of electrical and magnetic waves, which traveled in a direction normal to its traverse alternation,

The wave equation, known for long time before Maxwell, and applied to mechanical undulations of a rope, sound waves and heat, when was applied to the

electromagnetic theory, ended with a composite solution (used even today by engineers, physicists and chemists) wich contained the theoretical value of

the speed of light, Of course, as any other kind of wave, his velocity c= Wavelength x Frequency.

So, in Planck's time, frequency and wavelength of thermal radiation (visible light inclusive) was widely known and accepted.

Engineers still use newtons theories which are simpler than relativity and Maxwells equations which are simpler than QED. But QED and relativity gives a more accurate solution than Maxwells and Newtons equations.

A Photon we know has no electromagnetic properties it is has no charge and no magnetism. Virtual photons in  QED would be the same but might not even exist.

Until we get to extremely high energies photons dont interact with each other, https://en.wikipedia...-photon_physics These sort of energies are not normally observed on earth, unless you have a particle accelerator to hand.

I agree classically the maths works for maxwells equations but he is modelling a wave, generated from an alternating source with frequency. The source uses electricity or  magnetism to generate the wave, he assumes an electric field and magnetic field travel through space with the wave. But the wave does not interact with other waves as it travels through space. It is therefore wrong to view the wave as having electro magnetic properties. The wave is charge neutral, like a Photon. The only it is moving energy is via a wave which moves the electrons in the receiver, by imparting inertia to the electrons. Not unlike a real photon being absorbed by an atom and raising it to a higher energy level.

Photons being emitted from a source at 1/sec could be ascribed a frequency of 1 Hz. The energy of those photons is likely better described by Einsteins E=pv, rather than Plancks E=hf.

I understand using fourier analysis or digitising a wave anything can be ascribed a range of frequencies, but it does not give an accurate picture of the wave/quantum fluctuation unless you understand what the maths is trying to model. Currently photons are considered to be both waves and particles. Some people even think photons have magical electro magnetic properties, not realizing they have no charge or magnetic field, and are not influenced in anyway by other fields except gravity. The only force they carry is momentum.

There is absolutely no evidence I can find that shows a photon has frequency. Would you agree it is an assumption which comes from Maxwells Electro magnetic equations?

PS the speed of light is not constant in a gravitational field, Einstein said so in about 190?. c is only constant in free space away from gravitational fields.

### #8 OceanBreeze

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Posted 26 April 2019 - 03:40 AM

For me, it's very simple: to make a map with spatial observatories like COBE, WMAP and Planck (1989 - 2003), an extraordinary number

of events have to be ELIMINATED by digital filters and interpolations in powerful computers.

Have in mind that every one of these satellites measure the sky in an spherical perception, with a sphere with no radius (or infinite, if you like)

centered at the satellite.

The entire spherical "surface" of 4Pi steraradians is explored with a very narrow apperture with the satellite antennae, which requires thousands

The main problem is that, to obtain the background NOISE, emissions from our galaxy (the Milky Way) has to be substracted! And the energy values

from our galaxy are over a million times more powerful than the backgroud noise, and also is anisotropic!

Also, difractions caused by clouds of gases and plasma, and gravitational effect have to be discounted.

I don't believe that the results are VALID, because it requires to obtain an unknown value, which has a negative signal to noise ratio bigger than

- 60dB. And this, with stocastic processes that are the basis of radio transmission and reception, is directly IMPOSSIBLE.

You can detect a signal whose energy is under the capture signal by several dB, if you know HOW this energy behaves,

This is tha basis for Spread Spectrum modulation (military) and for CDMA coding mobile telephony (commercial), because

the pseudo-random signal below the noise level has a known pattern.

But, with analog signal with random values, it's impossible to rescue signal from high values of noise.

Then, I think that NASA and ESA are fudging results in order to fit the expected data (Planck's formula).

And adding to this, I think that it's incorrect to apply the Planck's formula to the Universe, assuming that

it behaves as a black body cavity, because it violates the original Kirchoff's law (1859), which leads to

Planck and others by 1900.

Why would NASA and ESA and everyone else engage in a conspiracy about the CMB?

Do you believe the moon landings were faked too?

Measuring the CMB is very easy to do, and I have done it several times myself.

We have several microwave/satellite dish antennae on board ship, the largest is 5 m diameter. With that dish I get about 4 K excess antenna T which can only be due to the CMB. I could probably do a better measurement if I had the time and inclination to do so, but I mainly am concerned with making sure the equipment is in good working order and measuring the CMB is a fun way of doing that.

Basically, the low noise amplifier’s equivalent noise temp NT is first characterized by switching the input between a cold load (liquid nitrogen) and ambient temperature. The “Y” factor and a little basic math gives the NT of the LNA. The antenna Temp is determined by pointing at a known radio source such as a radio star, the moon or a bore sight source. The system NT is the sum of the LNA T and the antenna T plus waveguide or coax losses.

Everything can be calculated beforehand and then compared with measurement.

When looking at what should be “cold sky” the system noise T is always higher than it should be by about 4 K in my case. That is the CMB signal that Penzias and Wilson accidentally stumbled on in 1964, much the same way that I see it; as excess antenna noise. In fact, it was predicted decades earlier and actually measured in 1941 to be 2.3 K by Andrew McKellar. It has been measured countless times using extremely accurate equipment and we now know it is about 2.7 K.

There is no conspiracy to see here!

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### #9 exchemist

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Posted 26 April 2019 - 09:11 AM

Engineers still use newtons theories which are simpler than relativity and Maxwells equations which are simpler than QED. But QED and relativity gives a more accurate solution than Maxwells and Newtons equations.

A Photon we know has no electromagnetic properties it is has no charge and no magnetism. Virtual photons in  QED would be the same but might not even exist.

Until we get to extremely high energies photons dont interact with each other, https://en.wikipedia...-photon_physics These sort of energies are not normally observed on earth, unless you have a particle accelerator to hand.

I agree classically the maths works for maxwells equations but he is modelling a wave, generated from an alternating source with frequency. The source uses electricity or  magnetism to generate the wave, he assumes an electric field and magnetic field travel through space with the wave. But the wave does not interact with other waves as it travels through space. It is therefore wrong to view the wave as having electro magnetic properties. The wave is charge neutral, like a Photon. The only it is moving energy is via a wave which moves the electrons in the receiver, by imparting inertia to the electrons. Not unlike a real photon being absorbed by an atom and raising it to a higher energy level.

Photons being emitted from a source at 1/sec could be ascribed a frequency of 1 Hz. The energy of those photons is likely better described by Einsteins E=pv, rather than Plancks E=hf.

I understand using fourier analysis or digitising a wave anything can be ascribed a range of frequencies, but it does not give an accurate picture of the wave/quantum fluctuation unless you understand what the maths is trying to model. Currently photons are considered to be both waves and particles. Some people even think photons have magical electro magnetic properties, not realizing they have no charge or magnetic field, and are not influenced in anyway by other fields except gravity. The only force they carry is momentum.

There is absolutely no evidence I can find that shows a photon has frequency. Would you agree it is an assumption which comes from Maxwells Electro magnetic equations?

PS the speed of light is not constant in a gravitational field, Einstein said so in about 190?. c is only constant in free space away from gravitational fields.

I would not agree with that a photon has no frequency and certainly not that Maxwell had anything to do with this.

A photon has an energy and a momentum, both of which imply a frequency, because of Planck's relation (E=hν) and De Broglie's relation (p =h/λ.) Both of these are relations from quantum theory. Maxwell's theory was a pre-QM, classical theory and so, by definition, did not involve photons.

What you may be thinking of is the problem that position and frequency cannot be simultaneously known, due to the Principle of Indeterminacy. Thus if one has a photon with an exactly known momentum (and thus frequency), one cannot know where it is in space, while conversely if one knows its location exactly, it is a Fourier superposition of infinite different frequencies and thus has an indeterminate momentum (frequency). In practice however one can can know both position and momentum (frequency) approximately, subject to a standard deviation of each given by:   σ(x) . σ(p) >/= h/4π .

Edited by exchemist, 26 April 2019 - 09:13 AM.

### #10 OceanBreeze

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Posted 26 April 2019 - 09:43 AM

I don't see how a photon can exist if it has no frequency.

### #11 exchemist

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Posted 26 April 2019 - 10:31 AM

Please, refer to the subject in my OP. It's about the use of Planck's spectral formula for thermal radiation within

a black body cavity (100% absorptivity of thermal energy).

What I question is the claim (NASA, ESA) that CBR perfectly fit the spectral values of Planck's formula using

frequency as variable, peaking at 160 GHz, assuming that the Universe behaves as a black body cavity.

Doing this, they equated what happens at a graphite cavity having a volume of 2,000 cm^3 with what happens

at the volume of the observable universe (8.7x10^69 Km^3). And this, besides violating Kirchoff's postulate, is

an utter nonsense (for me).

Penzias-Wilson measurements were made at a frequencies around 4.5 Ghz, which is probably close to the range

at which you conducted your on-ship measurements. But neither them, nor you did scan the entire spectrum, did you?

It is sad for me that, being a fact that science don't have a better formula to use than a 120 years old one (valid only at

a very restricted enviroment), the results are being published as if the verification of Planck's formulae at the entire

Universe is a breakthrough discovery. I think that this is false, misguiding for the general public and for autosatisfaction

of the people involved.

It's scary to register "things that happens out there" and not know what is it. But, trying to grab to something known here,

even WHEN IT'S NOT TRUE, is more scarier, because it is a sample of how far "the community" is willing to collude in

order to have peace of mind and keep getting public funds. Not to mention the fact that the CBR radiation is the single

more important support for the big bang theory.

I'd prefer that other means were used instead of black body cavity.

And regarding the term "conspiracy", with all the negative sides that it carries is far

from my thoughts. The meaning is (Google): "a secret plan by a group to do

something unlawful or harmful".

I prefer collusion: "secret or illegal cooperation in order to deceive others."

The world actually with collusion. My best example is the financial world and the

QE of money to hide economical depression. Or Big Pharma and statins, etc.

Plus, if you read my former posts on this thread, I consider IMPOSSIBLE to rescue

background noise right behind Milky Way radiation. Impossible.

It's similar to use algorithms to find the location of a given stellar object that is behind the

radiating edge of the Sun, by filtering the Sun's light at those places.

If such an impossible task were possible, we could be testing General Relativity any day,

any time, instead of waiting the screening of the Moon to measure light bending by gravity.

And this isn't happening, is it?

So, my original question stands firmly: Why Planck's formula is being used to validate the CBR?

There is a hidden agenda behind this. Not conspiracy, just collusion.

Why would anyone collude? The fact is we can observe the spectral distribution of the radiation and it follows the black body radiation curve. That is an observational fact and does not depend on any formula. https://en.wikipedia...a/File:Cmbr.svg

Given that the radiation takes the form of a black body distribution, it is logical to treat it according to the formula for, er, a black body. N'est ce pas?

Regarding the difference in size between a lab black body and the universe, as someone who clearly reads a fair bit of historical physics you ought surely to appreciate that the physical size of the body has little or nothing to do with the shape of the radiation curve it emits. A tungsten filament bulb is a pretty good black body emitter.

So I don't really understand what your beef is with using Planck's Law. It is merely the applicable law for any black body emitter.  And we know, from observation, that the CMBR is a black body radiation distribution.

Or am I missing your point?

Edited by exchemist, 26 April 2019 - 10:34 AM.

### #12 Flummoxed

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Posted 26 April 2019 - 01:25 PM

I don't see how a photon can exist if it has no frequency.

I do not see how it can have a frequency, it carries spin, polarization, and momentum at <=c. Nothing else can be confirmed about it. Frequency implies oscillation. No measurement has ever confirmed a photon has frequency.

### #13 Flummoxed

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Posted 26 April 2019 - 01:33 PM

I hope that you may agree with the fact that electromagnetic radiation is only one kind of phenomena, which can be explained with two different

perceptions depending on the application.

If you want a simplification, it could be: electromagnetic radiation is generated or absorpted using photons and travel using waves.

I would agree there is more than one way of viewing radio waves.

A minor correction electro magnetic radiation / radio waves consist of virtual photons, not photons.

### #14 exchemist

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Posted 26 April 2019 - 02:06 PM

I do not see how it can have a frequency, it carries spin, polarization, and momentum at <=c. Nothing else can be confirmed about it. Frequency implies oscillation. No measurement has ever confirmed a photon has frequency.

A photon is an oscillation in the electric and magnetic fields.

But, more generally, all QM entities have both particle and wave nature to them. An electron has a frequency, too. If it did not, we could not have the orbitals in atoms that correspond to standing wave patterns.

You say a photon has momentum. Well that means it has a wavelength, given by p=h/λ, and thus it has a frequency. This is basic quantum theory. Why do you think this is wrong?

### #15 exchemist

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Posted 26 April 2019 - 02:06 PM

I would agree there is more than one way of viewing radio waves.

A minor correction electro magnetic radiation / radio waves consist of virtual photons, not photons.

That is untrue. Radio waves consist of real photons, as does any form of EM radiation.

Edited by exchemist, 26 April 2019 - 02:07 PM.

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### #16 exchemist

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Posted 26 April 2019 - 03:06 PM

exchemist, I've read your historical posts and I found that you are a very knowledgeable person

in your field of expertise and beyond.

So am I.

about the decomposition in monopoles, dipoles, cuadrupoles, etc,, AFTER a thorough data filtering,

interpolation, extrapolation, etc. and then came here to tell me about observational facts.

The amount of computing time and meetings to agree with coincidences or discrepances about the

final data is extraordinary,

There is not a Galilei there, discovering Jupiter moons as an observational fact.

It's the same as if you tell me that ANY composed "photograph" of any distant galaxy is as it comes out

of the CCD camera, and it's not true that is heavily doctored to compose wavelengths from mm to nm,

covering a wide spectrum of microwaves, infrared, visible light, UV and X-Ray radiation.

And, as a final touch, an artist renders the final picture with a beatiful assignment of colors to make

the picture look more "beautiful".

This is a link to the basic theory behind the CBR mapping:

https://en.wikipedia...rical_harmonics

Greetings,

Richard

And yes, you are missing my point, but you are entitled to think differently, So let us to agree that we desagree.

So I don't really understand what your beef is with using Planck's Law. It is merely the applicable law for any black body emitter.  And we know, from observation, that the CMBR is a black body radiation distribution

Or am I missing your point?

What on Earth do spherical harmonics have to do with CMBR?

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### #17 OceanBreeze

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Posted 26 April 2019 - 03:27 PM

I would agree there is more than one way of viewing radio waves.

A minor correction electro magnetic radiation / radio waves consist of virtual photons, not photons.

That’s an interesting point of view!

However, about the only place you will ever see virtual photons is on a Feynman diagram, as they only exist as force-carriers for the Electromagnetic force that exists directly between charged particles. So, they only exist in static fields and are not detectable nor do they have energy or momentum.

Obviously, radio waves must consist of real photons as they do carry energy and momentum and are detectable.

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