[Dave Lev (OP)]

As far as we know, the universe has no "edge"

I knew that about 15 Years ago.
At that time the science community claimed that our universe is quite compact.
The black body radiation in the CMBR shows that our universe has no "edge" or infinite. (I can prove it if you wish)
However, why do you call it no "edge"?
What's wrong with Infinite Universe?

But the highest galactic redshift seen so far is HD1 at z=13.3

If we could jump to that far away galaxy, we would observe the same CMBR.
Therefore, do you agree that at any location that we will be in the universe with no "edge", it is expected to get the same CMBR from all directions?

One more question:
I had been told that If the Universe has no edge or infinity, then the Big Bang should take place at that infinite universe at the same moment.
Hence, based on the BBT, the whole universe with no edge was very hot at the first moment.
So how the expansion idea could cool down a Universe with no edge (or infinite universe) if all of it was already hot at the first moment?

[Bored chemist]

Therefore, the 3000K is a direct outcome from the BBT.

No.
It's a direct consequence of hydrogen.
If the material doing the emitting was helium, the corresponding temperature would have been roughly twice as high. (And the emission would have had more band structure to it).

The CMBR by itself has a redshift/blueshift that only indicates about our motion in the local space.

Where did it come from?
How is it so nearly homogeneous?
Why does it lack any band structure?

[Bored chemist]

However, there is no other/direct prof that the CMBR λobserved is 3000K.

Good.
Because lambda is not a temperature.
You have got the maths wrong as I pointed out here.

Z= (λobserved -λrest) / λrest
Z = (6275 – 2.75) / 2.75 = 2,281

Why did you suddenly shift from using wavelengths to temperatures?
Don't you see the problem there?

And nobody on a science page will take you seriously until you fix your maths .

Once you have got that correct, you need to explain what (apart from red shifted very hot hydrogen atoms) cold produce the right spectrum for the CMBR.
Remember, it has to look like BBR with no superimposed structure; no lines, no bands.

[Bored chemist]

At that time the science community claimed that our universe is quite compact.

Nope.
Here's what Wiki said 20 years ago.
"The size of the Observable Universe can be calculated as a sphere with a radius equal to the age of the Universe in light years. Thus the observable universe is a sphere with a radius of 15 billion light years. However due to initial inflation of the Universe soon after the Big Bang, the actual size of the Universe is much bigger than what is observable. ...
The Universe has no boundary but may be finite. This may be understood by a three-dimensional analogy: the Earth has no edge despite the fears of putative flat-earthers that they might fall off the edge if they travelled too far, but nonetheless the surface of the Earth has a finite area."

https://en.wikipedia.org/w/index.php?title=Universe&oldid=291910

Did you get confused about finite and bounded?

[Origin]

The real CMBR redshift only suggesting a motion of our galaxy of about 600km/sec?

Obviously not.  Since the the wavelength of the CMBR is the same in all directions, that would mean the galaxy is traveling in all directions at 600 km/sec, which hopefully you realize is not possible.

[Dave Lev (OP)]

At that time the science community claimed that our universe is quite compact.

Nope.
Here's what Wiki said 20 years ago.
"The size of the Observable Universe can be calculated as a sphere with a radius equal to the age of the Universe in light years. Thus the observable universe is a sphere with a radius of 15 billion light years. However due to initial inflation of the Universe soon after the Big Bang, the actual size of the Universe is much bigger than what is observable. ...
The Universe has no boundary but may be finite. This may be understood by a three-dimensional analogy: the Earth has no edge despite the fears of putative flat-earthers that they might fall off the edge if they travelled too far, but nonetheless the surface of the Earth has a finite area."

https://en.wikipedia.org/w/index.php?title=Universe&oldid=291910
Did you get confused about finite and bounded?

I do recall that in the past our scientists believed that the size of the Universe was about 92BLY.
However, this is not the issue.
As they claim today that the universe has no edge and it is bigger than a radius of 15 billion light years, than why they can't tell us how big it is.
You might claim that our scientists don't know. - I would claim that if they don't know the real size of the Universe, than how do they know that what they don't know is correct or incorrect?

the Earth has no edge despite the fears of putative flat-earthers that they might fall off the edge if they travelled too far, but nonetheless the surface of the Earth has a finite area."

If we discuss about the surface of the earth (two dimensions) than it has no edge, but in three dimensions it has a very clear edge.
However, there is no other real physical z dimension is our universe.
" The Universe, proper, is the single largest object with a name, and represents the culmination of full three-dimensional space interacting with time, forming a four-dimensional existence."
The space-time four-dimensional is excellent mathematical concept, but it doesn't add any real 4th physical dimension to our universe.
In the article it is also stated:
"There is some speculation that multiple universes exist in a higher-level multiverse. "

As our scientists are ready to consider so dramatic speculation of multiple universes exist in a higher-level multiverse, why they refuse to consider the possibility that the Universe could be just flat and infinite in its size?
Why our scientists are willing to consider all that possibilities/speculations for the universe just in order to bypass the key possibility that the universe could be infinite?
Could it be that they know that there is a possibility that the universe is infinite or at least - very very big.
Therefore, there is a possibility that any size that they might offer for the universe, would be too small for our real universe
However, if they would offer a too big size, (or even infinite) than the BBT would die.
So, could it be that in order to keep the BBT alive, our scientists bypass this key problem with the message of a "Universe with no edge"?

Therefore, the 3000K is a direct outcome from the BBT.

No.
It's a direct consequence of hydrogen.
If the material doing the emitting was helium, the corresponding temperature would have been roughly twice as high. (And the emission would have had more band structure to it).

I fully agree that the CMBR is a direct consequence of hydrogen as hydrogen is the most common atom in the nature.
However, why do you insist that the Atomic hydrogen welding (AHW) process (the 3000K) must be ALWAYS used in the CMBR redshift formula??

Let me ask you the following:
1. What is more dramatic speculation idea:
The idea of multiple universes exist in a higher-level multiverse, or the idea of a single flat & infinite Universe?
Do you agree that there is a possibility (at any chance) that the Universe is flat and is so big that technically it could be considered as infinite?
2. Do you agree that there is a possibility that the Universe age is much older than 13.8B years?
3. Do you agree that that there is a possibility that the CMB radiation is the reflection of that infinite Universe and not due to the Big bang that took place about 13.8By ago?
4. Even if the chance that the real CMBR reflects the radiation of the infinite universe is just one to one million of a trillion, why do you refuse to accept the understanding that in this very minor chance, the redshift in the CMBR can't be considered as 1100?

[Dave Lev (OP)]

The real CMBR redshift only suggesting a motion of our galaxy of about 600km/sec?

Obviously not.  Since the the wavelength of the CMBR is the same in all directions, that would mean the galaxy is traveling in all directions at 600 km/sec, which hopefully you realize is not possible.

The CMBR exhibits a dipole, suggesting a motion of our star in our galaxy of about 600km/sec, relative to the CMBR. https://astronomy.swin.edu.au/cosmos/c/Cosmic+Microwave+Background+Dipole

[evan_au]

the size of the Universe was about 92BLY....(or)  15 billion light years, than why they can't tell us how big it is.

There are some people on this forum who can explain this...

My simplistic understanding of what they said is:
- Roughly 15 (or 14) billion light years is the distance from "where the source was when the light was emitted" to "where we are now"
- Roughly 100 50 billion light years is the distance from "where the source is now" to "where we are now"
- There is an even smaller number (1.5 Million Light years) which represents the distance from "where the source was when the light was emitted" to "where we were back then"

As relativity illustrated, all times and distances are relative to which frame of reference you are talking about
- And anything outside your light cone is irrelevant to you (eg if some object is now 100 billion light-years away, light from that object will probably never reach us, due to the expansion of the universe).

I apologise to those whose clear-sounding explanation I have mangled.... Please post an accurate description.

PS: See more corrections from Halc, below

[Halc]

My simplistic understanding of what they said is:
- Roughly 15 (or 14) billion light years is the distance from "where the source was when the light was emitted" to "where we are now"

It's actually about 1/10000th of that. In cosmic coordinates (the only coordinate system I know that describes the universe), the oldest light we see (that of the CMB) was emitted at a proper distance of about 1.5 million LY away. The reason it took 13.8 billion years to get here is due to the very high expansion rate of the universe back at the time of the recombination event, perhaps 3M km/sec/mpc compared to 70 km/sec/mpc today.

Roughly 100 billion light years is the distance from "where the source is now" to "where we are now"

That would put it beyond the size of the visible universe which means we could not see it. So around 45 billion light years is the proper distance from "where the source is now" to "where we are now".

- There is an even smaller number which represents the distance from "where the source was when the light was emitted" to "where we were back then"

Well since we have not moved significantly in that time, that distance is also that 1.5 MLY figure. Cosmic coordinates has the Earth at the center, unmoving. You have to assign the origin somewhere.

As relativity illustrated, all times and distances are relative to which frame of reference you are talking about

Yes, which is why I carefully specified the cosmic frame and not say some inertial frame, which isn't valid at all at large distances since spacetime isn't Minkowskian.

And anything outside your light cone is irrelevant to you (eg if some object is now 100 billion light-years away, light from that object will probably never reach us, due to the expansion of the universe).

Correct. Any recombination light emitted from what is currently over about 58 BLY away will never reach us. Any light emitted today from over 16 BLY away will also never reach us. That latter figure is the current distance to the event horizon.

[Origin]

The real CMBR redshift only suggesting a motion of our galaxy of about 600km/sec?

Obviously not.  Since the the wavelength of the CMBR is the same in all directions, that would mean the galaxy is traveling in all directions at 600 km/sec, which hopefully you realize is not possible.

The CMBR exhibits a dipole, suggesting a motion of our star in our galaxy of about 600km/sec, relative to the CMBR. https://astronomy.swin.edu.au/cosmos/c/Cosmic+Microwave+Background+Dipole

I errored in my reply. 
The point is the CMBR is obviously not due to the our motion through space because the CMBR is very uniform in all directions, which would mean that for your idea to be correct we would have to be traveling in all directions, which is not possible.  By the way, a speed of 600 km/sec would give you only a very small wavelength shift and it would not be a uniform shift.

[Bored chemist]

I do recall that in the past our scientists believed that the size of the Universe was about 92BLY.

You "recall" things like this

I knew that about 15 Years ago.
At that time the science community claimed that our universe is quite compact.

But it' not true.

I would claim that if they don't know the real size of the Universe, than how do they know that what they don't know is correct or incorrect?

Yes, you would claim that but, as we have pointed out, your grasp of logic is shaky.
Uncertainty about the size of the universe doesn't stop scientists knowing things.

If we discuss about the surface of the earth (two dimensions) than it has no edge, but in three dimensions it has a very clear edge.

No, it doesn't.
It has a surface.
Please try to keep up with reality.

why they refuse to consider the possibility that the Universe could be just flat and infinite in its size?

Because that wouldn't be stable. It would collapse.

Grown-ups don't typically spend time on things that they know are impossible.

I fully agree that the CMBR is a direct consequence of hydrogen as hydrogen is the most common atom in the nature.

If the commonest atom in the universe was anything other than hydrogen, the CMBR would have a different spectrum.
Do you understand that?
There would be two differences.
It would have a different temperature
It would have a band structure.

For any element apart from hydrogen the CMBR wold have a band structure.
It doesn't.
So we know that the CMBR was formed by hydrogen.
And once we know what element emitted that radiation, we know what temperature it must have been at (because we know the recombination temperature).
And, since we know what the current temperature is, we can calculate the red shift.

Can you follow that logic?

why do you insist that the Atomic hydrogen welding (AHW) process (the 3000K) must be ALWAYS used in the CMBR redshift formula??

As I already pointed out, I
Quote from: Dave Lev on 04/02/2023 05:36:48
However, how do we know for sure that the CMBR λobserved is exactly the same as the "Atomic hydrogen welding"?
Nobody said they were.
The only person who got close is you.
Quote from: Dave Lev on 04/02/2023 05:36:48
So why we do not use the peak in the "Atomic hydrogen welding" to set the λobserved?
At the maximal level of 6000 °C (or 6273K) the redshift should be about:

Z = (6275 – 2.75) / 2.75 = 2,281

[Bored chemist]

1. What is more dramatic speculation idea:
The idea of multiple universes exist in a higher-level multiverse, or the idea of a single flat & infinite Universe?

The flat universe like that you suggested before is impossible so the other option is more plausible.

[Bored chemist]

. Do you agree that there is a possibility that the Universe age is much older than 13.8B years?

The question isn't well defined.
We certainly don't have any evidence of its existence before that time.
It is possible that it was farted by a unicorn.
But there is no science in any such speculation.

Certainly, the objects in the observed universe are not older than 13.8 Bn years.

Do you agree that that there is a possibility that the CMB radiation is the reflection of that infinite Universe and not due to the Big bang that took place about 13.8By ago?

No, it is not a reflection of an impossible thing.

. Even if the chance that the real CMBR reflects the radiation of the infinite universe is just one to one million of a trillion

It's not that big.
It is zero.

What could it be reflected in?

[Dave Lev (OP)]

Do you agree that that there is a possibility that the CMB radiation is the reflection of that infinite Universe and not due to the Big bang that took place about 13.8By ago?

No, it is not a reflection of an impossible thing.

Do you claim that Infinite universe is impossible?
How could it be that you are so sure about it?
In the following article it is stated that "Cosmologists aren't sure if the universe is infinitely big or just extremely large"
https://www.space.com/whats-beyond-universe-edge
"Cosmologists aren't sure if the universe is infinitely big or just extremely large. To measure the universe, astronomers instead look at its curvature. The geometric curve on large scales of the universe tells us about its overall shape. If the universe is perfectly geometrically flat, then it can be infinite. If it's curved, like Earth's surface, then it has finite volume."
So, there are two options for the Universe:
1. Infinite Universe - "If the universe is perfectly geometrically flat, then it can be infinite".
2. Finite Universe -  "If it's curved, like Earth's surface, then it has finite volume."
It is also stated:

"Current observations and measurements of the curvature of the universe indicate that it is almost perfectly flat."
Hence, based on the Current observations and measurements the universe is almost perfectly flat and therefore it is infinite.
However, it is also stated:
"But even if the universe is finite, it doesn't necessarily mean there is an edge or an outside. It could be that our three-dimensional universe is embedded in some larger, multidimensional construct. That's perfectly fine and is indeed a part of some exotic models of physics. But currently, we have no way of testing that, and it doesn't really affect the day-to-day operations of the cosmos."
"You might think this means the universe is infinite. But it's not that simple. Even in the case of a flat universe, the cosmos doesn't have to be infinitely big. Take, for example, the surface of a cylinder. It is geometrically flat, because parallel lines drawn on the surface remain parallel (that's one of the definitions of "flatness"), and yet it has a finite size. The same could be true of the universe: It could be completely flat yet closed in on itself."

Sorry, there is no other space dimension in our real universe.
It is a pure imagination to believe that if we will go all the way to the left in our real universe, then at some point we would come from the right (as in a cylinder Universe example).
If you wish to hold this imagination, first you have to prove that there is a 4th space dimension in the universe.

Quote from: Dave Lev on 08/02/2023 04:11:16
. Even if the chance that the real CMBR reflects the radiation of the infinite universe is just one to one million of a trillion

It's not that big.
It is zero.
What could it be reflected in?

As long as Cosmologists can't prove that there is a 4th space dimension in the universe then we all must understand that the universe must be infinite in its size.
The chance that the Universe has a 4th space dimension is Zero and therefore, the chance that the Universe is finite is also Zero.
They also add that even if it is finite - "our universe does indeed have an outside"
"Granted, it sounds impossible for there to be a finite universe that has nothing outside it. And not even "nothing" in the sense of an empty void — completely and totally mathematically undefined. In fact, asking "What's outside the universe?" is like asking "What sound does the color purple make?" It's a nonsense question, because you're trying to combine two unrelated concepts.
It could very well be that our universe does indeed have an "outside." But again, this doesn't have to be the case. There's nothing in mathematics that describes the universe that demands an outside."
I claim that the Black body radiation proves that there is no outside the Universe and therefore it must be infinite.
The CMBR that we get is the radiation of the current infinite Universe and therefore at any location that we would be in that infinite universe, we would get the same BB radiation.

I'm quite sure that all the Cosmologists know that.
However that breakthrough understanding might have negative impact on the BBT.
Therefore, in order to keep it alive they prefer to offer some unrealistic ideas as other dimension in space.

Hence, do you agree that as our "Cosmologists aren't sure if the universe is infinitely big or just extremely large" there is a possibility for infinite Universe?

Uncertainty about the size of the universe doesn't stop scientists knowing things.

Sorry, a theory for infinitely big or just extremely large Universe is different from a theory of compact finite Universe that had been created in only 13.8By!
Hence, the real size of the universe is critical for our understanding!

So please, do you agree by now that it is a severe mistake to claim that the CMBR redshift of the Infinite universe (or extremely large) is 1100?
Hence:
Can we agree that only the following message is correct:
CMBR BBT redshift is 1100

[Origin]

So please, do you agree by now that it is a severe mistake to claim that the CMBR redshift of the Infinite universe (option/possibility) is 1100?

No we cannot agree on that.  A universe that started at the big bang can still be infinite.

Can we agree that only the following message is correct:
CMBR BBT redshift is 1100

Sure.

[Dave Lev (OP)]

So please, do you agree by now that it is a severe mistake to claim that the CMBR redshift of the Infinite universe (option/possibility) is 1100?

No we cannot agree on that.  A universe that started at the big bang can still be infinite.

Thanks dear Origin
You are absolutely correct.
"A universe that started at the big bang can still be infinite"
Therefore, if the universe is infinite then you have to agree that the problem is not with the infinite universe but with the BBT.

Can we agree that only the following message is correct:
CMBR BBT redshift is 1100

Sure.

Thanks again
Hence, we fully agree that the 1100 is a direct out come from the BBT   

[Dave Lev (OP)]

Quote from: Dave Lev on 08/02/2023 04:11:16
why they refuse to consider the possibility that the Universe could be just flat and infinite in its size?

Because that wouldn't be stable. It would collapse.

Let's make it clear.
Only based on the BBT theory an infinite universe wouldn't be stable.
However, we might find other theory which can explain why an infinite universe could be perfectly stable.
Therefore, the impossible for the BBT might be very possible for other theory.
However, as long as our Cosmologists would keep the BBT and you would believe that the redfshift is there ONLY due to the BBT then it would stay impossible.

[Bored chemist]

Let's make it clear.
Only based on the BBT theory an infinite universe wouldn't be stable.

No.
Based on gravity and the conservation of energy a static universe would be unstable.

[Bored chemist]

Do you claim that Infinite universe is impossible?
How could it be that you are so sure about it?

OK I expressed myself poorly.
The reflection is impossible.
If you have a mirror that is infinitely far away, you can't see anything reflected it in.
I thought something that obvious didn't need a particularly careful explanation.

[Bored chemist]

As long as Cosmologists can't prove that there is a 4th space dimension in the universe then we all must understand that the universe must be infinite in its size.

Non seq.
And nonsense.
I don't need a cosmologist to tell me that we are in 4 dimensions.
That makes no difference to the size of the universe.

You posted that gibberish in response ot me asking  this

What could it be reflected in?

But your reply did not answer the question.
Try again.

Hence, we fully agree that the 1100 is a direct out come from the BBT

No.
I keep saying this and I don't think you understand that it is improtant.

For any element apart from hydrogen the CMBR wold have a band structure.
It doesn't.
So we know that the CMBR was formed by hydrogen.
And once we know what element emitted that radiation, we know what temperature it must have been at (because we know the recombination temperature).
And, since we know what the current temperature is, we can calculate the red shift.

Can you follow that logic?

Again, I'm asking you to actually answer a question which I asked.

Not responding to points that people raise means that you are preaching.
That will get the thread closed.
Is that what you want?