Is antigravity a bunch of hot air?

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22 years 3 months ago #2591 by AgoraBasta
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The in and out of the photon leaves the molecule as it was; no heating at all. The heating is quite a bit different.


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Jim,

Have you ever cared to look at the absorption spectrum of the atmosphere or individual gases? Whatever you base your statements upon - that's got no roots in reality...
(BTW, absorption-reemission can't leave momentum unchanged)

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22 years 3 months ago #2825 by Jim
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The photon is in and out without being changed so how is the molecule changed? You are not in the same ballpark with your model and maybe the molecule in the real world is changed-if so the photon is changed to.

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22 years 3 months ago #2592 by Gregg
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>The >photon is in and out without being changed so how is the molecule >changed? You are not in the same ballpark with your model and maybe >the molecule in the real world is changed-if so the photon is >changed to.

The "photon" is not a particle, but a wave. The re-emitted wave has less energy (lower frequency), leaving the molecule with a net gain in kinetic energy.

Gregg Wilson

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22 years 3 months ago #2620 by Jim
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You need to look at the total thread here to see that this problem is not about what real photons do to molecules. It is about how heat is generated and the QM model of this process.(In my opinion it is not an issue QM deals with in any way, but, that is onother matter) According to the QM model of the photon (E=hf where E is the photon energy; h is Planck's constant; f is the photon frequency)the photon is indivisible and must be absorbed and emmitted as a unit. The energy to heat one molecule is very little and the QM model is not able to show how the process of heating and cooling proceeds. We know the big picture is a black body that radiates in IR. The IR photons are still too energetic to cause only one molecule to heat up and so what seems a very simple process simply isn't.

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22 years 3 months ago #2594 by Youjaes
Replied by Youjaes on topic Reply from James Youlton
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>The >photon is in and out without being changed so how is the molecule >changed? You are not in the same ballpark with your model and maybe >the molecule in the real world is changed-if so the photon is >changed to.

The "photon" is not a particle, but a wave. The re-emitted wave has less energy (lower frequency), leaving the molecule with a net gain in kinetic energy.

Gregg Wilson
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I've been lurking here a bit to see where this conversation is going; however, I'd like to point out here that kinetic energy isn't a conserved quantity in the universe. A case in point is the eliptical orbits of celestial bodies. Angular momentum is conserved for orbiting bodies, but in the energy model there is gravitational potential energy which is basically assigned to an object based on its distance to the mass it is orbiting.

To Jim, keep going. I'm glad to see someone who doesn't automatically accept a simple solution because it is simple or popular.

James

(James, please leave out the "uninflamable" quip. I'd hoped you'd get the hint when I erased it six times. Thanks, monitor)

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22 years 3 months ago #2595 by Gregg
Replied by Gregg on topic Reply from Gregg Wilson

>To Jim, keep going. I'm glad to see someone who doesn't automatically accept a simple solution because it is simple or popular.

>James

>Ok, who put "Uninflamable" signs on gasoline tanker trucks?
[/quote]

In regard to the "photon" as a unit and how "heat" is transferred:

Take a rifle and fire a round at a heavy steel plate 100 yards away. At impact, the bullet will not retain its mass, its geometry and perfectly recoil back to your rifle, go up the barrel and reseat itself in the brass cartridge. Instead, the bullet will shatter into many pieces going in many directions at various speeds. The mass and the geometry of the bullet will not be conserved; they will be dispersed. The kinetic energy of the bullet will also be dispersed, with some of it becoming "heat" within the steel plate. This is entropy.

Now lets go to the photon. A photon is a human mental construct which is highly misleading because of it being interpreted as a particle. In the light carrying medium, you have waves. When a wave impacts against a molecule, the amount of wave energy taken in by the molecule is determined by the nature of the molecule. This amount of energy becomes dispersed by the molecule into a re-emitted wave of lesser energy, some translational energy, some rotating energy, some vibrational energy, perhaps a rise in electron energy, etc. The point is that the incoming energy gets dispersed. How the energy is dispersed will vary from molecule to molecule, depending on the status of each particular molecule.

When you measure this behavior with an instrument, the measure is a macroscopy average of countless millions of molecules over a long duration of time - long duration relative to a single molecular event.
Your measurement says that molecular nitrogen responds to a particular frequency of light in a certain way - on average. You don't measure a single event.


Gregg Wilson

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