Duplicatting the Sun

Thank you again In conclusion, I am going to use the dish to heat water. It already has a 350 degrees span and another motor that controls the vertical axis.

John

Yeah. the guy may turn out to be an expert at suitcase identification.

John

If you talk snotty you _are_ snotty. ...Jim Thompson

That brings back memories of an essay I read a long time ago as a teenager, I think it was by Isaac Asimov. It was a proof that you cannot have an infinitely old, infinite universe unless it is expanding.

Otherwise, if you draw a line from your eyeball in any direction, it will eventually terminate on the surface of a star. Essentially every part of the sky is the temperature of the surface of the sun, as would we be. The only reason this does not happen is that really distant stars are red shifted to nothing,i.e. the universe must be expanding. (Or not infinite, or not infinitely old - so the light from distant parts hasn't reached us yet).

Called Olbers' paradox.

Isaac did an article on it, as you said, to explain it to the masses. I think it appeared in his book The Universe. It also probably appeared elsewhere.

You should already know that the Son, along with the Father, and the Holy Ghost are already omnipresent, in your house and everywhere.

What will that do for your son?

That's called Olbers' Paradox. It proves that the universe is finite in either time or space, or else contains a finite number of stars.

Cheers

Phil Hobbs

Or has a bunch of dust.

John

No, because the dust heats up by absorbing the radiation, and has to re-radiate it eventually. As in electronics, there's no such thing as a heat sink. ;)

Cheers

Phil Hobbs

I don't believe that latter (dust) avoids the problem.

If you add dust to the situation (to e.g. block light from distant stars) then you have to account for what happens to all of the light hitting those dust particles from other angles. No matter whether the dust particles scatter all of this light, or absorb it and then re-radiate it, you'd end up with the same effect... each dust particle would look to us just as bright/hot as the average star, and Olbers' Paradox would still apply.

The only way that dust could avoid Olbers' Paradox, was if the light hitting each dust particle actually vanished without effect (e.g. fell into a wormhole).

OK, then we can apply the anthropic principle to the problem. Since we exist and can think, the universe is finite or contains a finite number of stars. Otherwise we'd be incinerated.

John

Or it expands (which it does).

Any line drawn from the eyeball terminates on the surface of a "star" all right [1], but it is redshifted to 3 degrees kelvin...

That's the one, I forgot that name for it.

It was elsewhere I read it, one of his books of collected essays. I probably read it 50 times as a kid, can't even remember the title now :(

Would it be possible to tell the difference between the 3K radiation of a random distribution of increasingly red-shifted stars and an equally red-shifted wall of ionized gas somehow?

Jeroen Belleman

Hmm, I would hope so, since that was supposed to be one of the major pieces of evidence for the big bang wasn't it? Perhaps Phil H will tell us. (Or Martin Brown when he turns up, he's our resident astronomer AFAIK).

Or said wall, cooled to 3K? If it were randomly spaced stars, wouldn't there be red-shifted versions at 4K?

Sure, but since they are much too far away to be resolved, we'd only measure a diffuse averaged background. The same would work for whole galaxies, a billion times further away.

I'm no physicist, so bear with me, but instead of the universe expanding, can't we think of some other mechanism for red shift, like some weak long-distance Compton scattering or some such effect? There's a lot of distance to hide it in, and the effect would be far too subtle to be noticed over small distances. (Like, less than a Mpc or so. :-) ) Tired light, anyone?

As for Olbers' paradox, that then tells that the average energy density of the universe corresponds to a 3K temperature.

The Big Bang has its problems, hasn't it? Matter popping out of nowhere, missing antimatter, superluminal inflation, expansion of nothingness and doubtlessly much other ad-hoc theoretical subterfuge I haven't even any notion of.

We're drifting way off topic, as usual.

OK, shoot me.

Jeroen Belleman

Jeroen wrote in news:j6saiq$1sl$1 @speranza.aioe.org:

Maybe, if you could measure the spectral line width of part of the radiation, the stars would produce broader lines due to their rotation. In practice, the energy in the 0-3 kelvin band might be to weak to resolve into separate spectral lines.