So that was my point from the beginning - how can the momentum be conserved if the Carbon dioxide molecule is already travelling against the momentum of the photon?

So you get the situation where unless the photon can conserve its momentum it won't interact with the electrons on the Carbon Dioxide molecule. It can clearly be seen that the electron has to be either stationary or at least have momentum in the direction of the photon's momentum vector before conservation of momentum can occur.
That then leads to the conclusion that GHG when they heat up the atmosphere also provide an impetus to super-rotate the planet for there is more heating occurring on the side going away from the source of the photons (the Sun) than on the side approaching the source.
So the planets covered with GHG will experience an intensified wind in the direction of rotation. This intensified wind will exert a drag effect on the planet's surface and over the lifetime of the planet contribute to the angular velocity of spin and hence shorten the planet's "day length". 



1. Can the implications for weather can be so easily codified. Venus, has a GHG problem and both high temperatures and high winds, but I am unsure they are entirely consistent your above conclusions.

2. That bit aside over time the length of an earth day has grown. There was some mention that the Earth had a day that was as short as six hours and the moon was near close enough to touch.

3.  Think about the mass and momentum of the Earth compared to the atmosphere... Any affect of atmospheric winds on the rotation of the earth must happen over a time scale that would make them insignificant when compared to many other forces in play.

4.  But there is another aspect of likely more significance, the motion of GHG molecules in the atmosphere are generally random and average out. So the real significance is that while the sun shines they allow heat in and when it does not that act as an insulator to prevent its escape. 


5. The energy and the momentum of a photon are both linearly proportional to its frequency, so of course they are linearly proportional to each other. Also the photon can Compton scatter off a free electon - In fact Compton X-rays have so much energy that even a bound electon is "free" to them. A plasma will scatter light, not very much as very low density, but not so low when normalize by "electons per cc").

Due to scattering´s "random walk" nature and other things, a photon at the solar core, may take many months (YEARS, I SEEM TO RECALL) to escape to solar surface and then gets to earth in only 8.5 minutes, but it is a little strange to say this as the photon energy changes drastically during the process reaching the surface to a much lower value.

For "earth shine" IR radiation the CO2 might absorb there are no elections removed from the CO2. Also the IR rotational and vibrational absorption band are not due to movement of an electron alone. It is the whole molecule, which is linear of the form: o--c--o. I can not draw for you it rotating but there are two distinct form of pure vibration:

(1)Symetric stretch: o-c-o going to o---c---o and back again

(2) A-symetric stretch: o-c--o going to o--c-o and back again.

In addition there are the flex modes (which are harder to type draw):
o.......o
....c.... (ignore all dots - they are just to keep Sciforum´s compter from compressing multiple spaces down to one.)
Going to:
....c....
o.......o

(Billy T) 

       
Posted by OnlyMe

Well this only applies to the current Earth situation in a very minor way as the GHG are only a small fraction of the Earth's atmosphere.
Add to that the effect of tidal angular momentum transfer to the Moon which is slowing the Earth. So there are two opposing effects and they are beyond sorting them out.

But as you point out prior to the Moon (being a slowing influence) the Earth was roaring around at a frightening rate, and fully covered with a range of GHG at that time.

Venus definitely doesn't have a Moon now but was thought to have had one. The collision of it's moon may have stopped it spinning the way all other (bar 1) planets do (counter clockwise) so I think of Venus' atmosphere speeding up its rotation in the way it is now going.

Jupiter is the prime example of this effect on the planets spin. No scientist can offer the reason it spins as fast yet I believe the effect I have described accounts for some of it.

The other planets I'm just not sure about at this stage of my study.

Also the random nature of the heating only appears on the Earth where the atmosphere is clear enough for the sunlight to strike the land surface. On planets orbiting the Sun, even if they were not rotating with respect to the stars, as they orbited the Sun, from the Sun's perspective the planet will rotate once per year. Hence as far as the incoming radiation from the Sun is concerned the photons absorbed by GHG will tend to occur on the side appearing to be going away from the Sun, not the approaching side.
Now I do realise that due to the angular momentum in the planetary dust disc, from the beginning, it is unlikely that the forming planets did not have some spin from the very beginning. 


I think I agree with what you have said. The IR appears to always interact with an electron, but it doesn't cause ionization in the case of IR radiation. The electron is not ripped off. But it is advanced and that advancement causes the molecule to vibrate. That vibration (like plucking the string on a guitar was started by a distinct motion, stretching the molecular bonds (but not breaking them). That distinct motion is in the direction of the momentum vector so with time the molecule as a whole moves in the same direction as the "strum".

Continuing the analogy of the guitar. If the guitar was on a frictionless surface and it was continually strummed "downward" across the strings it would overcome inertia and move in the same direction as the strum.