I was intrigued when you said that the photon would 'peter out' and that's when I was sure you were confused. photons, once created, travel in a straight line until they interact with matter. (yes gravity can have a small effect, expansion of the universe even smaller). yet you were saying they just disappear.
I don't know how many times I have to point this out, or how many times I have to post the defintion of photon. Clearly you are imagining that a photon is this "thing" that goes zipping about the universe and just keeps on going till such time as it hits something. A photon is the smallest quantum of an EM field. Until you understand and accept that, you are not going to be able to grasp what is happening. So, AGAIN, I am going to provide you with a definition of what a quantum is, and what a photon is.
quantum - Plural quanta
A discrete, indivisible manifestation of a physical property, such as a force or angular momentum. Some quanta take the form of elementary particles; for example, the
quantum of electromagnetic radiation is the photon, while the quanta of the weak force are the W and Z particles.
Now the definition of photon:
photon - The subatomic particle that carries the electromagnetic force and
is the quantum of electromagnetic radiation. The photon has a rest mass of zero, but has measurable momentum, exhibits deflection by a gravitational field, and can exert a force. It has no electric charge, has an indefinitely long lifetime, and is its own antiparticle. See Note at electromagnetic radiation. See Table at subatomic particle.
Just for the hell of it, here is the note at electromagnetic radiation:
electromagnetic radiation
Energy in the form of transverse magnetic and electric waves. In a vacuum, these waves travel at the speed of light (which is itself a form of electromagnetic radiation). The acceleration of electric charges (such as alternating current in a radio transmitter) gives rise to electromagnetic radiation. Other common examples of electromagnetic radiation are x-rays, microwaves, and radio waves.
A single unit, or quantum, of electromagnetic radiation is called a photon
I don't know how many ways I can describe this to you. A photon is the smallest unit of an EM field. It is a packet of energy. Being a "packet" of EM energy, it can be expended against anything that might require energy to overcome. You are laboring under the impression that a photon zips along until such time as it hits something. That something to you is apparently a solid object, but that simply is not true. An EM field is something and when a photon moving in one direction along any vectro as part of an EM field encounters photons coming from the opposite direction along the same vector that are parts of an EM field, you must subtract the magnitudes of the two EM opposing EM fields in order to determine in which direction the energy will be propagated. When you subtract the fields, you are, in effect, subtracting photons. Energy is being expended to overcome the weaker field which leaves the field with the greater mangitude diminished but still propagating energy flow in its original direction and the energy of the weaker field is expended in the diminishment of the greater field.
The bits of energy that photons represent are expending themselves against the opposing EM field. I repeat a photon that is part of an EM does not have to hit a solid object in order to cease its existence. Of course if you direct an EM field against a 10 foot thick lead wall, the energy would be expended against the wall, but an EM field also expends energy in overcoming another EM field and when energy is expended, photons cease to exist.
Perhaps I am still misunderstanding you. please describe the type of field you are talking about, why it interacts with GHG emissions in the atmosphere, and how it removes or 'peters out' the photon in the absence of matter.
What you are misunderstanding is the nature of photons. Are you laboring under the impression that an EM field can only be overcome by matter? That an EM field simply continues forever until it hits some object of sufficient mass to stop it? If so, then you couldn't possibly be more mistaken. Photons are the "stuff" EM fields are made of and there is no argument that along any vector, if two EM fields are in opposition, the field of greater mangitude determines the directon of energy flow. There is no two way energy movement along any vector.
thanks for your consideration. I am sure we can come to a better understanding with a clarification of positions much faster than just speaking past each other.
i have not been speaking past you. I have made every effort to try and explain this to you but you seem to be completely unwilling to alter the misinformed image in your head of what a photon is. You see it as this thing that just goes on forever till it hits some bit of matter and that is not an accurate image. In EM fields, photons represent the smallest possible bit of energy that makes up the EM field. As energy is expended, whether it be against a brick wall, or against another EM field, photons are "winking" out of existence. When the bit of energy that each photon represents is expended, that photon ceases to exist.
I don't know how else to describe what is happening to you. Till you get this idea that a photon goes on till it hits a solid object out of your mind, you will never be able to accurately grasp what is happening.
If you accept that one EM field can overcome another by expending energy till the other field is "defeated" and still have energy left (although diminished) to continue moving in its original direction, and you can accept the well known fact that EM fields are made of photons... that photons are the "stuff" that make the field and are the smallest possible bit of energy in the field, and can accept that when fields oppose each other, the energy represented by photons is being used up in opposition to the other field, then, and only then, can you grasp what is going on.