Stewart Robert Hinsley wrote:

In message , Sleepalot
writes

I was thinking about the greenhouse effect, and this question
occured to me: in the space around me, what's more common,
atoms or photons?


In the universe as a whole the photon to baryon ratio is 10^9.

Lol. Ok, I've looked up "baryon" - it's neutrons and protons, but
not electrons, yes? Is the universe still amost entirely hydrogen?


So the
question that now needs to be answered is by how much is the baryon
density (and photon density) enhanced in the space around you, and what
is the average number of baryons per atom in that region. The answer to
this depends on how big a space you're thinking of.

I did have a further think, bearing in mind this is a
near-the-Earth-surface situation. So, around here
1 litre of air contains about 1 Avogadro number of
atoms.

For photons, I'm working from my understanding of
cathode ray tubes: an electron hits an atom of
phosphor, causing the emmision of a photon.

So an amp of cathode current (way too high) would be
a coulomb of electons per second giving an equal
number of photons.

So (say) 10mA would be 10^16 photons per second
in 10^23 atoms .....no that's wrong because those
photons wouldn't hang around that long.

Does this make sense? Am I on the right track?


--
Sleepalot aa #1385