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On Tue, 02 Jun 2009 19:34:43 -0300, Nicolas Alvarez wrote:
> Jim Henderson wrote:
>> You know that 78.67% of all statistics are made up, right?
>
> One in five dentists agree.
62.3% of the time, in any event. :-)
Jim
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> Content of the universe = 10^80 atoms
>
> (I can't seem to find an estimate for the number of subatomic particles in
> the universe. Since the universe is 75% H, 23% He and only 1% O, I guess
> there isn't going to be a huge difference - unless you count non-matter
> particles like photons, etc.)
I wonder how many photons typically exist? I mean is it 10^10, 10^50,
10^100 or what? You could probably do some estimate with output power from
stars etc.
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"scott" <sco### [at] scott com> wrote in message
news:4a264021$1@news.povray.org...
> > Content of the universe = 10^80 atoms
> > (I can't seem to find an estimate for the number of subatomic particles
in
> > the universe. Since the universe is 75% H, 23% He and only 1% O, I guess
> > there isn't going to be a huge difference - unless you count non-matter
> > particles like photons, etc.)
> I wonder how many photons typically exist? I mean is it 10^10, 10^50,
> 10^100 or what? You could probably do some estimate with output power
from
> stars etc.
Googling photon to proton (or baryon, in general) ratio yields about 10^9.
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scott wrote:
> I wonder how many photons typically exist?
Mu.
That is the answer that unasks the question.
The question doesn't make sense to ask. If you didn't look at the photon, it
might or might not have existed. Then there are virtual photons, which come
and go, which by definition you cannot look at.
There's probably some statistical thing that'll tell you some expected
numbers, but it's not really the same question.
--
Darren New, San Diego CA, USA (PST)
There's no CD like OCD, there's no CD I knoooow!
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Darren New wrote:
> scott wrote:
>> I wonder how many photons typically exist?
>
> Mu.
>
> That is the answer that unasks the question.
>
> The question doesn't make sense to ask. If you didn't look at the
> photon, it might or might not have existed. Then there are virtual
> photons, which come and go, which by definition you cannot look at.
>
> There's probably some statistical thing that'll tell you some expected
> numbers, but it's not really the same question.
How about gravitons then? :-D
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Jim Henderson escreveu:
> On Tue, 02 Jun 2009 21:56:53 +0100, Orchid XP v8 wrote:
>
>> Jim Henderson wrote:
>>
>>> You know that 78.67% of all statistics are made up, right?
>> I heard it was 82.1%...
>
> No, new research has shown that (statistically speaking) fewer statistics
> are made up than was previously thought. :-)
what a relief! :)
--
a game sig: http://tinyurl.com/d3rxz9
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> The question doesn't make sense to ask. If you didn't look at the photon,
> it might or might not have existed.
You can estimate the number of photons coming off a star though, can't you?
Just multiply that figure by the estimated number of stars in the entire
universe and that's a start for the lower bound.
> There's probably some statistical thing that'll tell you some expected
> numbers, but it's not really the same question.
Well that's why I said "typically" rather than asking for an exact number
:-)
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scott wrote:
>> The question doesn't make sense to ask. If you didn't look at the
>> photon, it might or might not have existed.
>
> You can estimate the number of photons coming off a star though, can't
> you? Just multiply that figure by the estimated number of stars in the
> entire universe and that's a start for the lower bound.
That would be a lower bound on the non-virtual photons, yes. Of course,
there are heptazeptazillions of photons deep inside each star being created
and destroyed. It takes about a million years for a photon created in the
sun to actually get to the surface. Count those?
>> There's probably some statistical thing that'll tell you some expected
>> numbers, but it's not really the same question.
>
> Well that's why I said "typically" rather than asking for an exact
> number :-)
I'm not sure that "typically" means what I'm talking about. I'm talking
about photons that by definition don't exist long enough to be measured. Do
you want to count them? There are, by the math, potentially infinite numbers
of them, which is what makes doing the actual math of QED difficult.
--
Darren New, San Diego CA, USA (PST)
There's no CD like OCD, there's no CD I knoooow!
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> That would be a lower bound on the non-virtual photons, yes. Of course,
> there are heptazeptazillions of photons deep inside each star being
> created and destroyed. It takes about a million years for a photon created
> in the sun to actually get to the surface. Count those?
Well if we know the rate of photons coming off the star, and each one has
lived for a million years previously, then you could make some estimate.
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scott wrote:
>> That would be a lower bound on the non-virtual photons, yes. Of
>> course, there are heptazeptazillions of photons deep inside each star
>> being created and destroyed. It takes about a million years for a
>> photon created in the sun to actually get to the surface. Count those?
>
> Well if we know the rate of photons coming off the star, and each one
> has lived for a million years previously, then you could make some
> estimate.
Only if you knew how much light was going to be coming out in a million
years, and only if you knew the ratio of photons generated to photons
escaping. :-)
--
Darren New, San Diego CA, USA (PST)
There's no CD like OCD, there's no CD I knoooow!
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