[Vern]

Yes; it will radiate as much power as it receives; it is continually doing this; its radiating ability is not cumulative since it radiates constantly. So it simply radiates at the temperature of ambient space.  This is as Eddington postulated.

[LeeE]

Why is there a universe?

Because somewhere was needed in which to put everything.

Like an overgrown garden shed

Yes, or a loft.

[angst]

Angst / Vern
The Olber Paradox is not resolved on the grounds of dust and gas in between*. It is only resolved by, either a finite or expanding situation. That's what I meant by a red herring. As soon as you accept that light energy reaching us from distant stars is less and less OR that there are no stars beyond a certain distance, the paradox disappears.

* In an infinite Universe, each grain of dust would be receiving energy from all directions from stars and would heat up to the same temperature as the average star - thermal equilibrium would be reached. The dust would appear white hot to us.

This makes no sense. If the universe is finite, and we say that we measure that finite value and call it U. A universe that is 2U would not be hotter or brighter at any given location - unless you suggest otherwise? A universe 4U would, likewise, not be hotter or brighter at any given location. Extrapolate onward....

[lyner]

Are you just asserting that or have you a proof?
Where is the error in the following?

If the Universe is finite, there will be gaps in between the stars that you see, If you make it bigger, then some of these gaps will have stars in them, providing more energy to the observer or to a piece of dust. The temperature of the dust will be high enough for thermal equilibrium -  until
energy in = energy out.
The bigger you make the Universe, the more energy arrives at your piece of dust so the temperature of the dust will be higher. For infinite size, the temperature would be the same as the stars.

If what you said were true then, with just one star and one piece of dust, the sky would be just as bright as it is at a point in our galaxy.

[Vern]

But you can't have it both ways. You can't say that the CMBR is the remnants of the Big Bang and the contribution from star light is negligible while still maintaining that starlight would cause a blazing hot universe if the universe was infinitely large.

Warmed space debris would gain energy from starlight and radiate it back into space. It could never reach the temperature of the stars. It must be a process, not a cumulative effect.

I have not crunched the numbers, but the Eddington group claimed to have done so. I don't have access to the Eddington study; and I can't produce my reference. So we may have to just agree that we disagree.  []

[lyner]

I'm not proposing it as a model for the universe. As I said. I'm explaining where the Olber paradox ceases to be a paradox. I thought my earlier post made that clear.
My arguments assume a finite or non expanding model, which we all(?) now reject.

Eddington et al knew this when they did the sums.

[Vern]

I guess the situation we're thinking about may be too speculative to make sense of. I was thinking of an infinite spacial universe in which light behaved in accord with Halton Arp's Tired Light scheme. I'm not sure we can dismiss that idea based upon the paradox.

It is probably not important. []

[lyner]

Arp post dates Olber by a very long time and he also post dates Eddington.
Olber's paradox can be resolved in very conventional terms and without going much further forward in time from Olber. The dust issue can be dealt with entirely in classical terms also. It is a red herring because, in an infinite Universe it would be just as hot as the rest of the sky and, in a finite universe (ignoring issues like c and gravity etc) it would still adopt the mean temperature of the sky.

There is no point in hopping forwards and backwards by centuries or by  models  if you don't need to. Tired photons or Hubble Red Shift are just an extra factor to the argument if we already acknowledge that the Universe is finite.

Is there still any serious idea that the Universe is infinite?

[Vern]

I wouldn't say that too loudly [] Poor Halton Arp might take offence. Poor guy thinks he's still alive []

I don't think we have knowledge that the universe is finite. I haven't ruled out the possibility that it is infinite.

[lyner]

I wouldn't say that too loudly [] Poor Halton Arp might take offence. Poor guy thinks he's still alive []

I don't think we have knowledge that the universe if finite. I haven't ruled out the possibility that it is infinite.

"Post date" doesn't imply he's dead, does it?

[Vern]

Oops; sorry; I read that as pre-dates.  My bad. []

[lyner]

tut tut! []

[Limejuice]

God created matter - thats where everything started

[Vern]

God created matter - thats where everything started

What created God?

[dentstudent]

He is omnipresent, and so that doesn't need an answer. That's handy, eh?

[Vern]

Yes; I've heard that convenient answer many times. [] My response has always been: why not simplify and just say the universe is omnipresent. Leaves out one step. But; I'm afraid we diverge from the topic and so might be justly chastised for so doing. []

[guest10038]

I  agree  with  vern  that  their  was  no  'Big  Bang'  and  this  Universe  always  existed.This  Universe  is  so  vast  that  we  can't  even   imagine  and  I  think  it  is  not  possible   that  only  a  'Big  Bang'  create   this  Infinite   Universe.

[lyner]

Yes; I've heard that convenient answer many times. [] My response has always been: why not simplify and just say the universe is omnipresent. Leaves out one step. But; I'm afraid we diverge from the topic and so might be justly chastised for so doing. []

Hear hear.

[itisus]

Why is there a universe?

If there was a big bang, what came before it, and before that, and so on?

Surly nothing should be, but it is, why?  

Here is the quick answer:  It depends on what is defined as "nothing."
If nothing is the absence of any possibilities, then no thing is possible. (Duh!)  BTW, a Creator is no help in this case because it would first have to be a possibility, and however much a modal logician might want to make it possibly necessary or necessarily possible, it would still have to first (and last and always) be possibly possible, which by definition of "nothing" it cannot be.

If "nothing" is actually a possibility of things, then it cannot be selecting which things are possible because that would make it "something" by any reasonable definition.  So we start with a Void in which anything is possible.  However, if it is detectable by the Void, then its negation should also appear.  That, in my opinion, is why everything is so hard to define, because it is all concealed from any potential outside observer, at least for a long time. 

[itisus]

I wouldn't say that too loudly [] Poor Halton Arp might take offence. Poor guy thinks he's still alive []

I don't think we have knowledge that the universe is finite. I haven't ruled out the possibility that it is infinite.

Infinity is a limit, not an actual quantity.