Is the universe infinite or finite?

[Polymath257]

So if the radius is expanding I dont know how that is "incorrect". Also I dont understand if the so called "expansion factor" exists and the radius is expanding at a critical rate, the universe is infinite.

The 'radius' for the critical expansion rate isn't a radius: it is an expansion factor. And, yes, in the model, at the critical expansion factor, the universe is always infinite (also true for negative curvature, by the way). Your not understanding is primarily due to you not looking in detail at the math involved.

The only other possibility for a 'flat' space is a toroidal universe. Essentially, space would be periodic in that model.

 

[firedragon]

The 'radius' for the critical expansion rate isn't a radius: it is an expansion factor. And, yes, in the model, at the critical expansion factor, the universe is always infinite (also true for negative curvature, by the way). Your not understanding is primarily due to you not looking in detail at the math involved.

The only other possibility for a 'flat' space is a toroidal universe. Essentially, space would be periodic in that model.

Hmm. So the hot Big Bang model works with a flat space? Omega = 1? No radius as you say. The universe is always infinite, infinitely expanding, no radius, but is also flat. No radius of the universe which is the curve of time vs radius/temperature!

 

[Polymath257]

Hmm. So the hot Big Bang model works with a flat space? Omega = 1? No radius as you say. The universe is always infinite, infinitely expanding, no radius, but is also flat. No radius of the universe which is the curve of time vs radius/temperature!

Yes, that is correct. It has an expansion factor (usually set to 1 for the current time) and that expansion factor grows over time.

 

[syo]

Infinite.

 

[firedragon]

Yes, that is correct. It has an expansion factor (usually set to 1 for the current time) and that expansion factor grows over time.

Expansion factor, but is an "r" which "radius". Is the radius infinite but is still expanding?

Can you demonstrate an observable infinity that is expanding?

 

[firedragon]

Infinite.

Great. So which model do you propose is the correct one and why?

 

[syo]

Great. So which model do you propose is the correct one and why?

I don't know any models.

I suspect you mean universe=space. Space is limitless. So the universe/space is infinite.

 

[firedragon]

I don't know any models.

I suspect you mean universe=space. Space is limitless. So the universe/space is infinite.

Thats not what this thread is about. Also, the universe is not equal to space. Also, space being limitless would depend upon your model. The universe is not space, space is only a part of the universe.

I hope you understand.

 

[Polymath257]

Expansion factor, but is an "r" which "radius". Is the radius infinite but is still expanding?

Can you demonstrate an observable infinity that is expanding?

For an infinite expanding space, r does not represent a radius. It represents a ratio of sizes

 

[firedragon]

For an infinite expanding space, r does not represent a radius. It represents a ratio of sizes

HBB. Radius of the universe. radius/temp. Time.

I think I have repeated this enough.

 

[paarsurrey]

Is the universe infinite or finite?

Since Universe is a creation of God/Allah/YHVH, so relative to the Creator it has to be undoubtedly finite, I understand, please.
Right?

Regards

 

[Polymath257]

HBB. Radius of the universe. radius/temp. Time.

I think I have repeated this enough.

Yes, you have. Have you actually studied cosmology? Have you actually worked through the equations you are talking about?

I have. In the Hot Big Bang model, the r is NOT a radius. it is an expansion factor. Yes, it is inversely related to temperature.

How many times do I need to repeat this?

 

[night912]

HBB. Radius of the universe. radius/temp. Time.

I think I have repeated this enough.

Repeating incorrect information about HBB due to ignorance, still won't convince someone with a correct understanding of HHB, into accepting that it's true.

 

[firedragon]

Yes, you have. Have you actually studied cosmology? Have you actually worked through the equations you are talking about?

I have. In the Hot Big Bang model, the r is NOT a radius. it is an expansion factor. Yes, it is inversely related to temperature.

How many times do I need to repeat this?

No Polymath. Only you have studied.

have a super day.

 

[firedragon]

Repeating incorrect information about HBB due to ignorance, still won't convince someone with a correct understanding of HHB, into accepting that it's true.

What is incorrect? Can you explain clearly?

 

[Polymath257]

What is incorrect? Can you explain clearly?

It is incorrect to say that the Hot Big Bang variable r represents a radius. You also seem to be confused about the difference between the radius of the observable universe and the radius (whether or not it exists) of the universe.

For example, one way of writing the line element for a flat expanding universe is

ds^2 = a^2 (t) [ dt^2 - dx^2 -dy^2 -dz^2 ]

The a(t) represents an expansion factor NOT a radius. This is one of the forms that is used in the HBB model. The specifics of the function a(t) depend on things like energy density and compressibility of the different types of energy.

It is the function a(t) that is also often written as r(t) and that you are mistaking for a radius.

 

[firedragon]

It is incorrect to say that the Hot Big Bang variable r represents a radius. You also seem to be confused about the difference between the radius of the observable universe and the radius (whether or not it exists) of the universe.

I did not ask for a radius in an observable universe. Please do go back and read that carefully.

ds^2 = a^2 (t) [ dt^2 - dx^2 -dy^2 -dz^2 ]

The a(t) represents an expansion factor NOT a radius. This is one of the forms that is used in the HBB model. The specifics of the function a(t) depend on things like energy density and compressibility of the different types of energy.

It is the function a(t) that is also often written as r(t) and that you are mistaking for a radius.

Let me say this again. I am talking about the "RADIUS" in the HBB model. The curves are radius and temperature of the universe.

I am not saying this is absolute. The question I asked about the infinite universe was not based on observation or an observable universe.

 

[rational experiences]

Space says a human brain is flat without any form in it. As missing owns a human explanation what never existed.

Then you say it is stretched as it has form within it. Burning made space stretch and cooling contracts.

Forms within hence have to both burn and shrink theirselves.

Therefore objects have a thin flat plane surrounding it with no internal space. Said by humans thinking.

Infinite imposed cannot measure it as it has no dimensions.

Inference always to where you are men Sion and di. Di meaning thinking about two conditions at once.

A human asking a human question wants human ideas as opinions. Human.

As measuring is imposed only by a human. Form does not measure itself.

So thinkers human said you cannot apply a measure to space and quote it infinite meaning owning no number itself.

 

[Polymath257]

I did not ask for a radius in an observable universe. Please do go back and read that carefully.

OK, so you are asking about whether the universe is finite or infinite in extent. good.

Let me say this again. I am talking about the "RADIUS" in the HBB model. The curves are radius and temperature of the universe.

And once again, I am telling you *there is no radius in the HBB model*. There is an expansion factor. And yes, the temperature is inversely related to the expansion factor. I am guessing this is the curve you are talking about.

I have pointed this out several times. I can understand why you *think* there is a radius in the HBB model because the expansion factor is often designated by R or r.

BUT IT IS NOT A RADIUS.

Do you understand what I am saying?

I am not saying this is absolute. The question I asked about the infinite universe was not based on observation or an observable universe.

In that case, there is no radius for a flat space. There is an expansion factor.

Do I need to supply a reference for this?

 

[firedragon]

And once again, I am telling you *there is no radius in the HBB model*. There is an expansion factor. And yes, the temperature is inversely related to the expansion factor. I am guessing this is the curve you are talking about.

I have pointed this out several times. I can understand why you *think* there is a radius in the HBB model because the expansion factor is often designated by R or r.

BUT IT IS NOT A RADIUS.

Do you understand what I am saying?

Radius.

In that case, there is no radius for a flat space. There is an expansion factor.

Do I need to supply a reference for this?

No. Try and answer the question I asked.