So far as I understand photons are particles of energy that are produced when an electron moves down an orbit. That emitted photon bounces off of objects and because of the evolution of our eyes we see the colors that the object doesn't absorb. Sometimes not all of the energy is absorbed so that photon continues to bounce around until it's fully absorbed. My question is does the photon that is absorbed and then emitted continue to be transferred between objects infinitely? Please correct me about any miss understandings I have and if possible try and simplify as much as possible. Thanks!
Asked
Active
Viewed 109 times
3
-
Sometimes not all of the energy is absorbed so that photon continues to bounce around until it's fully absorbed. Do you mean bounce around in the object until it is absorbed by the object, or do you mean the photon bounces around outside of the object until it is absorbed by our eye? – BioPhysicist Jan 15 '20 at 18:04
-
Thanks for asking for the clarification Aaron and as I understand it the photon continues to bounce around in the object until it is fully absorbed and then the object emits the photon but in a different form that is produced as visual light but is the same energy as the photon. Again please correct me if I'm wrong. Light fascinates me very much but I seem to have a hard time grasping the subject. – Zachary Wells Jan 15 '20 at 18:13
-
3Photons are indistinguishable from each other, if you are concerned on whether we can judge whether the same photon is at use one place or another. – Jan 15 '20 at 18:31
-
@user47014 Other than frequency and polarization – Bill Alsept Jan 15 '20 at 22:34
-
@Bill Alsept Yeah a photon's frequency and polarization can change also. – Jan 15 '20 at 23:00
-
@Bill Alsept also position is different and changes. But that's all not what I was addressing. I was talking about whether we can say the same photon comes out of something that goes into it, and whatnot. – Jan 15 '20 at 23:20
-
@user47014 In that case there’s only two choices. A photon impacts exciting an electron which then emits a new photon or the original photon is refracted Orr scattered. – Bill Alsept Jan 15 '20 at 23:28
-
@Bill Alsept Yes the OP says "the photon that is absorbed and then emitted", hence my comment. – Jan 15 '20 at 23:31
-
Ok, thank you for the info about the distinguishing of photons and how they change their frequency, polarization, and position. – Zachary Wells Jan 16 '20 at 18:06
2 Answers
1
So far as I understand photons are particles of energy that are produced when an electron moves down an orbit.
They are, particles, the gauge bosons of the electromagnetic interaction in the quantum mechanical field theory model of particle physics. In addition to being absorbed and emitted by atomic transitions of electrons, they can also be emitted by accelerating charged particles.
That emitted photon bounces off of objects and because of the evolution of our eyes we see the colors that the object doesn't absorb.
It is much more complicated than that. The light our eyes register is an emergent effect of the quantum mechanical superposition of a very large number of photons. Thus a large number of individual photon interactions with the cones in our eyes are interpreted by the brain as "light". Equally important, there is perception of color, which is a biological effect that interprets color in the brain.
Sometimes not all of the energy is absorbed so that photon continues to bounce around until it's fully absorbed.
Once a photon interacts and loses part of its energy, it is a new photon, with smaller frequency because its energy is equal to h*ν. Consecutive scatters will lead to eventual absorption of the energy of the original photon.
My question is does the photon that is absorbed and then emitted continue to be transferred between objects infinitely?
As said above,no, it is not the same photon, consecutive photons of consecutive bounces have smaller and smaller energy, until they are absorbed by the lattice of the material ( which has infrared bound states).
anna v
- 233,453
-
The light our eyes register is an emergent effect of the quantum mechanical superposition of a very large number of photons. Although the eye is pretty good at seeing individual photons :) – BioPhysicist Jan 16 '20 at 03:03
-
1
You are asking whether photons are absorbed and emitted infinitely. Now it is very important to understand that photons are elementary particles, and they are indistinguishable.
Photons are boson, so it follows the Bose-Einstein statistics which is only true if the particles are truly indistinguishable. If you can distinguish between two photons, then it will follow the classical Boltzmann statistics which is not what happen in experiments. That means photons with same properties are the same.
Same photon or different photon?
Photons can have any energy (frequency) though. But the very important thing is, when a photon is absorbed, it ceases to exist as photon, and transforms into the energy of the absorbing electron/atom.
We cannot talk about that specific photon anymore, because it ceased to exist as photon. It from that moment on exists as energy (inside the electron/atom system).
When the same electron/atom system emits consequently a photon, that is not the same photon. Photons do not have a licence plate. You cannot identify them like that. Even if the photon that is emitted has the same energy (frequency), that is not the same photon anymore.
Energy is what is eternal, and quanta of energy (photons) bounce all around, get absorbed, emitted, as you say, but that does not mean that we are talking about the same photon, but just the same amount of quanta of energy (if it is the same energy/frequency). The underlying world is QM, and energy is what gets transformed, and propagates.
Árpád Szendrei
- 28,452