[Bored chemist]

So how can you claim that it doesn't apply if you are inside the container/cavity?:

Because i'm inside a part of the galaxy (as it happens, my cellar) and for reasons that will never be explained, I have stuck a bowl of  blue glass over the light fitting.

According to the local radiation in here it's well over 30,000 Kelvin.
But I'm still here.

[Bored chemist]

The "photosphere" was clearly explained by Wiki:

Yes, it is well enough explained.

Now, please explain to me why you think my toaster has one.

[Dave Lev (OP)]

"Red hot" means something that's emitting BBR in the range where it's just about hot enough to start producing visible radiation.

So. like a candle flame, a red hot iron mar (or a toaster, if you like) is a source of black boy radiation.

Thanks for this information.
I assume that you mean "red hot iron bar" instead of "red hot iron mar"
So, you actually offer an option to generate a BBR without the need for "Photosphere".
That is perfectly OK
So, we can add the following option for our Universe to carry a a black body radiation in its CMB:

3. If the Universe acts as a "red hot iron bar" than it could carry a BBR in the CMB without the need for photosphere.

Hence, we can agree that the Universe could be finite without any need to set a Photosphere around it (if the Universe was a "red hot iron bar").
However, do you consider that this option is real?
If our scientists had considered that this option is valid, than they wouldn't offer the BBT as the only source for the BBR in the CMB.
Therefore, it is clear that even our scientists do not consider that our Universe  acts as a "red hot iron bar".
Therefore, we still have only the following two options:

Therefore, as the CMB is the radiation of our Universe, there are only two options:
1. The universe is finite with photosphere around it
2. The Universe is infinite. I have proved why an infinite sphere/universe should also generate BBR.
As we clearly know that there is no photosphere around the Universe, than an infinite sphere (or Universe) is the only valid solution for the BBR in the CMB

Any other idea?

[Bored chemist]

Any other idea?

Yes.
That's why I posted it; three times.
Not sure why you ignored it- presumably because it's not compatible with what you want to believe.

Here it is again.

Because i'm inside a part of the galaxy (as it happens, my cellar) and for reasons that will never be explained, I have stuck a bowl of  blue glass over the light fitting.

According to the local radiation in here it's well over 30,000 Kelvin.
But I'm still here.

Therefore, inside the cavity there must be a BBR

Which part of "no" do you not understand?

Do you still not understand that it doesn't apply if you are inside the container or if there are light sources inside the container with different effective temperatures?

[Dave Lev (OP)]

Do you still not understand that it doesn't apply if you are inside the container or if there are light sources inside the container with different effective temperatures?

I have already sent you my reply about those issues.
In any case:
1. How can you claim that the BBR doesn't apply if you are inside the container?
I have deeply explained that issue and backup it with articles:

You miss the whole point of Black body radiation.
https://en.wikipedia.org/wiki/Black_body
"Any light entering the hole is reflected or absorbed at the internal surfaces of the body and is unlikely to re-emerge, making the hole a nearly perfect absorber. "
So, in order to get the black body radiation, the light entering the hole is reflected at the internal surfaces of the body and is unlikely to re-emerge.
Therefore, the "small hole in a container" or a Cavity with a tinny hole is only used to sample the internal radiation without negatively impact the creation of the black body spectrum due to the internal reflections:
Please see one more example for: "An approximate realization of a black body as a tiny hole in an insulated enclosure"
https://en.wikipedia.org/wiki/Black_body#/media/File:Black_body_realization.svg
Again, in order to get a black body signature in the radiation the light should be reflected by internal surfaces of the body or photosphere.
Is it clear to you by now?

It seems that you didn't understand that explanation.
So, let me use the following example:
We set a tinny hole in a cavity.
With that tiny hole we actually monitor the internal radiation in the cavity.
So you claim that if we monitor the internal radiation through that tinny hole, we should find that the radiation carry BBR, while if we monitor it from inside we shouldn't get the BBR.
Is it real? How could you believe in such unrealistic idea?
On which kind of article do you base that wrong understanding?

2. How can you also claim that if there are light sources inside the container with different effective temperatures we shouldn't get the BBR?
In wiki it is stated that a cavity could be consider as an oven?
https://en.wikipedia.org/wiki/Black-body_radiation
Black-body radiation becomes a visible glow of light if the temperature of the object is high enough.[21] The Draper point is the temperature at which all solids glow a dim red, about 798 K.[22] At 1000 K, a small opening in the wall of a large uniformly heated opaque-walled cavity (such as an oven)
It is stated that:
"No matter how the oven is constructed, or of what material, as long as it is built so that almost all light entering is absorbed by its walls, it will contain a good approximation to black-body radiation."
So, inside that oven there could be one heating element or unlimited no of elements. As long as it is built so that almost all light entering is absorbed by its walls, it will contain a good approximation to black-body radiation.
I have also offered the sun as a perfect example for black body radiation while at its surface you can find different arias at different temperatures at any given moment:

With regards to the different effective temperature:
Actually, if we monitor the surface temperature of the sun we should find temporarily arias/spots with different temperatures.
That doesn't negatively impact the BBR of the Sun.

So how can you claim that if there are several light sources inside the container with different effective temperatures it won't work?
Again, on which kind of article do you base that wrong understanding?

[Dave Lev (OP)]

Infinite Universe

I hope that by now we all do understand that the main meaning of a Black body radiation in the CMB is Infinite Universe.
If we go to the infinity at our left side, we will stay at the left.
Same issue with any other direction that we will chose to go.
Our Universe isn't singularity and there is no expansion in space.
It is fixed in short range as it is fixed in a very long rang.
Only the matter/Galaxies are expanding in all directions.
I have already explained why the farther galaxies are residing at a faster speed.
The Atlantic Ocean had been created due to a 2cm drifts per year.
So, a very vast ocean could be created if we give it enough time.
In the same token an infinite Universe could be created from a single BH after long enough time.
Therefore, in order to generate an infinite Universe an infinite time is needed.
Hence, our Universe must be infinite in its age.

[Kryptid]

I hope that by now we all do understand that the main meaning of a Black body radiation in the CMB is Infinite Universe.

Nope. It's still a non-sequitur.

[Dave Lev (OP)]

I hope that by now we all do understand that the main meaning of a Black body radiation in the CMB is Infinite Universe.

Nope. It's still a non-sequitur.

Dear Kryptid

Sorry, it seems that I have missed your following reply.

If you think that my conclusion about the size/age of the universe is "non-sequiturs", than would you kindly tell us about the real size of our Universe?

You don't seem to know what a non-sequitur is: https://en.wikipedia.org/wiki/Formal_fallacy
Trying to get me to tell you about the real size of the Universe in order to counter your claims is an example of shifting the burden of proof: https://en.wikipedia.org/wiki/Burden_of_proof_(philosophy)#Shifting_the_burden_of_proof It is not up to others to falsify your idea. It is up to you to support it.

As Usual - thanks for your great answer.
You claim that my understanding is incorrect due to  burden of proof.
So, let's try to understand what is the meaning of burden of proof:
https://en.wikipedia.org/wiki/Burden_of_proof_(philosophy)
"The burden of proof (Latin: onus probandi, shortened from Onus probandi incumbit ei qui dicit, non ei qui negat) is the obligation on a party in a dispute to provide sufficient warrant for their position."
 
Let's focus on: "the obligation on a party in a dispute to provide sufficient warrant for their position" and see the diffrence in our positions with regards to CMB - Cosmic Microwave Background Radiation:

What is Radiation?
https://www.cdc.gov/nceh/radiation/what_is.html
Radiation is energy that comes from a source and travels through space at the speed of light. This energy has an electric field and a magnetic field associated with it, and has wave-like properties. You could also call radiation “electromagnetic waves”.

It is also stated:
https://en.wikipedia.org/wiki/Radiation
"The word radiation arises from the phenomenon of waves radiating (i.e., traveling outward in all directions) from a source. This aspect leads to a system of measurements and physical units that are applicable to all types of radiation. Because such radiation expands as it passes through space, and as its energy is conserved (in vacuum), the intensity of all types of radiation from a point source follows an inverse-square law in relation to the distance from its source. Like any ideal law, the inverse-square law approximates a measured radiation intensity to the extent that the source approximates a geometric point."

Therefore, if there is a constant source of radiation at a given point source, than "the intensity of all types of radiation from a point source follows an inverse-square law in relation to the distance from its source."
Therefore, we can easily calculate the amplitude of the radiation at any given distance from the point of source.

Based on those explanations it is quite clear that the radiation that we monitor at our location is a combined radiation that we get from any radiation source point around us.
Therefore, the CMB represents the combined radiation that we get from our current Universe. That radiation is generated by almost infinite number of radiation source points in the whole Universe. It could be a nearby star or very far end galaxy.
So simple and clear.
This explanation fully meets the basic element in Burden_of_proof "to provide sufficient warrant for their position".

However, our scientists think differently,
Somehow they are positively sure that the CMB is a remnant from an early stage of the universe?
https://en.wikipedia.org/wiki/Cosmic_microwave_background
"The cosmic microwave background (CMB, CMBR), in Big Bang cosmology, is electromagnetic radiation as a remnant from an early stage of the universe, also known as "relic radiation".

Why is it?
Can you please prove that unrealistic idea?

I hope that you agree that any bang, even if we call it a Big bang isn't a constant source of radiation.
So, this big bang might generate an ultra high temporary radiation that travels at the speed of light.
However, once it cross the space, it should gone forever especially as it took place 13.8 BY ago.
So, how could it be that our scientists believe that the radiation from the Big bang could stay with us after so long time?

Sorry, this big mistake of our scientists fully meets your explanation about Formal_fallacy.
If our scientists can't show how the CMB radiation could stay in space for almost 13.8 BY, than they violet the basic element in Burden_of_proof "to provide sufficient warrant for their position

So, the CMB radiation should be the radiation of our current Universe, while any other assumption is a clear Formal_fallacy even if it is made by our scientists.

The other issue is Black body radiation in the CMB.
Why our scientists are so sure that a bang could generate a black body radiation?
In all the explanations about black body radiation, I have never ever found even one word about bang that could generate that kind of radiation.
As an example, we get a radiation from a supernova. Do we see there a black body signature in the radiation spectrum?
https://en.wikipedia.org/wiki/Supernova
In that article they deeply discuss about the radiation of the supernova. However, you won't find even one word about black body radiation.

So, if our scientists claim that the black body is due to the Big bang, than they must "provide sufficient warrant for their position" that a bang can generate a black body radiation.
Without it, the assumption that the CMB is a remnant from an early stage of the universe is just one more Formal_fallacy from our scientists.

[Bored chemist]

I hope that by now we all do understand that the main meaning of a Black body radiation in the CMB is Infinite Universe.

No.
If I was inside a wine cellar with cool walls at a  nice even temperature, and the lights off, I would see black body radiation in whichever direction I looked corresponding to the temperature of the walls- probably about 280K.

That does not mean that the cellar is infinite.

In the same way, when we look out and see the CMB, it does not mean the universe is infinite.

You are still presenting an unjustified assertion.
The burden of proof is on you.

It would also be on you if you were claiming, without valid grounds, that the Universe is finite.

The point is simple.
You make the claim; you have to prove it.

[Dave Lev (OP)]

Hello Bored chemist

Thanks for your excellent example:

If I was inside a wine cellar with cool walls at a  nice even temperature, and the lights off, I would see black body radiation in whichever direction I looked corresponding to the temperature of the walls- probably about 280K.

So, you actually offer that wine cellar as an example for a container/cavity.
You show that a black body radiation could be generated at that wine cellar while you are inside.
Therefore, you have just proved that we can stay at the container and get a black body radiation.
Hence, I hope that by now you clearly understand that your following message was totally wrong:

Do you still not understand that it doesn't apply if you are inside the container.....?

So, yes, you can be inside the container and still get a BBR.

With regards to the following:

That does not mean that the cellar is infinite.
In the same way, when we look out and see the CMB, it does not mean the universe is infinite.

Yes, I fully agree with you.
The black body radiation does not mean that the wine cellar is infinite.
It just shows that it has walls all around it.
So, the wine cellar is a perfect example for a black body radiation in finite object that is surrounded by walls (or photosphere).

Therefore, I have stated that due to the BBR there are two options for our Universe:

So, if we see a radiation with a BBR it proves that there must be some sort of photosphere around the light source.
Therefore, as the CMB is the radiation of our Universe, there are only two options:
1. The universe is finite with photosphere around it
2. The Universe is infinite. I have proved why an infinite sphere/universe should also generate BBR.
As we clearly know that there is no photosphere around the Universe, than an infinite sphere (or Universe) is the only valid solution for the BBR in the CMB

Therefore, as we can't prove that our universe acts as a wine cellar (that fully covered with walls or photosphere), than finite Universe is clearly can't generate a black body radiation.

In the same way, when we look out and see the CMB, it does not mean the universe is infinite.
You are still presenting an unjustified assertion.
The burden of proof is on you.

I hope that by now you finely agree that once we take out the walls from the wine cellar (while you stay at the center of that object), you won't get the BBR any more.
Therefore, a finite Universe without walls all around it can't meet the BBR signature that we see in the CMB.
Hence, the only way to get a BBR from any kind of sphere without walls is when this sphere is infinite.
I have already deeply explained that issue.
Therefore, as our Universe generate BBR in its CMB (and as it has no walls or photosphere all around it), than it must be a infinite.
This conclusion fully meets the burden of proof as it fully provides sufficient warrant for this position.

[Dave Lev (OP)]

If I was inside a wine cellar with cool walls at a  nice even temperature, and the lights off, I would see black body radiation in whichever direction I looked corresponding to the temperature of the walls- probably about 280K.

I would like to focus on the CMB temperature.
We see exactly the same temperature from all directions.
So, if our Universe was finite, than we had to be located exactly at the center of this finite Universe.
What is the chance for that?
Is it 1/10^100 or shall we agree on just zero?
Hence, a finite universe would never generate exactly the same CMB temp in all directions (if we aren't located exactly at the center).
Therefore, this is key evidence that our Universe must be infinite.
At infinite sphere there is no meaning for a center point.
Any point at the infinity universe could be considered as its center.

The point is simple.
You make the claim; you have to prove it.

Agree
I have just proved that our universe must be infinity in order to supply exactly the same radiation from any direction at any location.

However, now it is the obligation of our scientists to answer the following questions:
1. Why the CMB is not the radiation of our current Universe
2. How could it be that a BBR is created by a Bang (even if we call it big bang)? Please offer valid explanation for that!!!
3. How "a remnant from an early stage of the universe, also known as "relic radiation" could stay in the open space for more than 13.8BY, while I have offered an article from wiki that radiation should cross the space at the speed of light.
4. Why the radiation amplitude of the CMB is measured by time from the BBT instead of a distance from the bang source point? Why we do not calculate the radiation amplitude by "inverse-square law"
Please remember, it was stated at wiki:
"the intensity of all types of radiation from a point source follows an inverse-square law in relation to the distance from its source."
If you claim that time represents distance, than we are currently moving away from the singularity point of the Big bang at almost the speed of light. However, as the radiation is also moving at the speed of light, than how could it be that we get any radiation from that Big Bang that took place 13.8 BY ago?
5. If the universe is finite, than how could it be that we see the same CMB temp in all directions?
6. How the CMB could carry a BBR while there are no walls around our finite Universe.
Please remember it was clearly stated in wiki that a BBR can only be created at a cavity or photosphere. Without a cover for our finite Universe, there is no way to keep a BBR in our universe for so long time.

Hence, without real answers for all of those questions, it is clear that our scientists have totally failed in the burden of proof as they can't provide sufficient warrant for their position...

[Bored chemist]

We see exactly the same temperature from all directions.
So, if our Universe was finite, than we had to be located exactly at the center of this finite Universe.
What is the chance for that?

No, once again, imagine the wine cellar scenario.
It wouldn't matter if I was nearer to (say) the South wall, the radiation would look exactly the same, not matter which way I faced unless I looked at myself.

[Bored chemist]

Hence, I hope that by now you clearly understand that your following message was totally wrong:

No
Once again, you missed the most important bit.

inside a wine cellar with cool walls at a  nice even temperature, and the lights off,

Obviously, if I'm in the cellar and I look at myself, I see a different temperature.
But the effect I have on the cellar as a whole, is small.
Someone peeping in through a small hole in the wall  would see my spectrum, or the wall's or some combination, depending where they looked.
That's why you can't say that a small hole in a container gives BBR unless you have no light source in the container.
And that's why you are wrong.

[Bored chemist]

Why the radiation amplitude of the CMB is measured by time from the BBT instead of a distance from the bang source point?

Because there isn't a "point".
The big bang is everywhere.

You really need to try to understand  the theory before you try to undermine it.

[Bored chemist]

How "a remnant from an early stage of the universe, also known as "relic radiation" could stay in the open space for more than 13.8BY, while I have offered an article from wiki that radiation should cross the space at the speed of light.

Because the universe is big.
Even at the speed of light it takes the radiation billions of years to cross it.

[Bored chemist]

Hence, without real answers for all of those questions, it is clear that our scientists have totally failed in the burden of proof as they can't provide sufficient warrant for their position...

It's time I got back to work but, trust me, all those questions have perfectly sensible answers.
It's just that you haven't done your homework and found out what they are.

[Dave Lev (OP)]

Dear Bored chemist

First let me thank you for all your efforts in responding my messages.
I'm looking forwards for your homework/answers.

It's time I got back to work but, trust me, all those questions have perfectly sensible answers.
It's just that you haven't done your homework and found out what they are.

However, would you kindly backup your understanding by real physics law?

For example, you claim that the radiation would look exactly the same at any location at the finite Universe::

We see exactly the same temperature from all directions.
So, if our Universe was finite, than we had to be located exactly at the center of this finite Universe.
What is the chance for that?

No, once again, imagine the wine cellar scenario.
It wouldn't matter if I was nearer to (say) the South wall, the radiation would look exactly the same, not matter which way I faced unless I looked at myself.

Hence, I hope that by now you clearly understand that your following message was totally wrong

No
Once again, you missed the most important bit.
Quote from: Bored chemist on Yesterday at 19:23:03
inside a wine cellar with cool walls at a  nice even temperature, and the lights off,

Obviously, if I'm in the cellar and I look at myself, I see a different temperature.
But the effect I have on the cellar as a whole, is small.
Someone peeping in through a small hole in the wall would see my spectrum, or the wall's or some combination, depending where they looked.
That's why you can't say that a small hole in a container gives BBR unless you have no light source in the container.
And that's why you are wrong.

So you discuss on a cellar. As I have already explained a cellar has walls around it and therefore it acts as cavity.
It generates BBR and I even might agree with you that is could generate the same temp.
However, we discuss on a finite Universe without any walls around it while we are located at any location in that Universe (even almost at its edge)..
So, if for example we are located closer to the left side edge of a finite Universe (without walls), than the total radiation sources from the left side should be much lower that the right side.
Therefore, based on the inverse-square law, the combined radiation from the left side should be lower than the right side.
This is a simple outcome due to physics law. Therefore, the radiation temp at the left side should be much lower than the right side.
I have backup this explanation by article from Wiki:

https://en.wikipedia.org/wiki/Radiation
"The word radiation arises from the phenomenon of waves radiating (i.e., traveling outward in all directions) from a source. This aspect leads to a system of measurements and physical units that are applicable to all types of radiation. Because such radiation expands as it passes through space, and as its energy is conserved (in vacuum), the intensity of all types of radiation from a point source follows an inverse-square law in relation to the distance from its source. Like any ideal law, the inverse-square law approximates a measured radiation intensity to the extent that the source approximates a geometric point."

Therefore, if there is a constant source of radiation at a given point source, than "the intensity of all types of radiation from a point source follows an inverse-square law in relation to the distance from its source."
Therefore, we can easily calculate the amplitude of the radiation at any given distance from the point of source.

Based on those explanations it is quite clear that the radiation that we monitor at our location is a combined radiation that we get from any radiation source point around us.
Therefore, the CMB represents the combined radiation that we get from our current Universe. That radiation is generated by almost infinite number of radiation source points in the whole Universe. It could be a nearby star or very far end galaxy.

So, it is clearly stated that: "the intensity of all types of radiation from a point source follows an inverse-square law in relation to the distance from its source"
Hence, if you still think differently, than please backup your understanding by real article & physics law.
Just to say "No" because I know better than you, wouldn't bring us to the real solution.

[Bored chemist]

"the intensity of all types of radiation from a point source follows an inverse-square law in relation to the distance from its source"

And again, you miss the point.
"from a point source"
A wall is not a point source.

Please go and learn some physics.

[Dave Lev (OP)]

And again, you miss the point.
"from a point source"
A wall is not a point source.

Please go and learn some physics.

Any matter, any star and any galaxy acts as point of source in our universe.
Therefore, if at the left side there are much less points of source with regards to the right side, than by definition the combined radiation temp at the left side should be lower than the right side.
Why is it so difficult?
Remember - we discuss on a Universe without walls.

[Bored chemist]

Remember - we discuss on a Universe without walls.

OK, let's start with the case where there are well defined walls  like my cellar.
When you get that right, we can move on.
OK, imagine I look at the wall through a tube- like, for example, the cardboard one from the middle of a toilet roll.
And imagine that the wall is a perfect crystal with lots of atoms in a regular array.
Now imagine counting how many atoms I can see through that tube.
Well, it depends on the aspect ratio of the tube. That defines the angle over which I can see.
Lets say the tube is 9cm long and 3cm in diameter.
And let's also assume, that I'm 90cm from one wall (South) , and 900 cm from the other (North)

OK facing South, I can see a patch of wall 30 cm in diameter and facing North I can see a patch that's 300 cm in diameter.
One circle is 100 times the area of the other.
So I can see 100 times as many atoms when I look North as wann I look South.
But (and this is why it matters that a wall is different from a point) each atom is 10 times further away and, because of the inverse square law that applies to point sources (like atoms, but not like walls) I only receive 100 times less light from each atom.

So I see 100 times more atoms, each giving me 1/100 times as much light.
The two effects cancel exactly.

So the light I see does not depend on the distance from the wall.

Now, if you think about it, you will see that the same thing happens regardless of the distances to the walls, or the length or diameter of the tube.

So the tube might as well not be there.
You will still get exactly the same degree of illumination, regardless of your distance from the wall.
The inverse square law applies to every atom in the wall, but the number of atoms you can see increases as you move away so the two effects exactly cancel.

So, next time I suggest that you go and learn some physics, perhaps you should do so.