A while ago, maybe a year or so a thread discussed the issue that seemed no to be adequately addressed in current csientific thought.

The point of origin of the photon and how it manages to go from a relative zero velocity to 299792kmps and yet maintainit's invariance.

Possibly some one can inform the board of what they have come to know about this acceleration phase if there is an acceleration phase and how this is in accord with the postulates.
Another issue that is similar is when a photon is reflected how does it do this with out slowing down, stoipping and then acceleerating again, [if the same photon is involved}

So in summary I would like to discuss point of origin and reflection acceleration factors for our photon.

Care to discuss? :)

Later question first. I do not think that the reflected photon is the same photon, but would not bet a large sum on this opinion.

I do not think photons come into existence and then accelerate to the speed of light. Photons are Quantum World objects, and should not be expected to act like the objects we think we see and understand in the classical world of our senses. It is my opinion that photons come into existence traveling at the speed of light. Once again, I would not bet large sums of money on this opinion.

On second thot, I might bet large sums on my opinions. How could those opinions be proven wrong in my lifetime? It would be very difficult to tag a photon approaching a mirror and record that the reflected photon had the same identifying tag. Assuming that it was created with no velocity, what sort of apparatus could measure the acceleration of a newly created photon?

QQ,
You seem to have a picture in your head of a photon forming, then shooting away at light speed - something like a photon torpedo in Star Trek.

I suggest that your mind-picture might not be a reasonable model of reality.

I suggest that your mind-picture might not be a reasonable model of reality.

Well Pete, that's why I am asking the question.... a reasonable model of the scientific communities model maybe.

I think possibly you have just told me why I have asked the question and not addressed the question it self.....hmmmmm.....well done.

Textbooks generally describe electromagnetic radiation as having properties of waves and particles. The particle is what's called the photon, and textbooks further define the waves as having an electrical and magnetic component perpendicular to each other and perpendicular to the direction of motion as shown in this picture.

http://vcs.abdn.ac.uk/ENGINEERING/lasers/pic1.gif

But this isn't a very good visualization if you ask me. When a photon is created, it exists in a superposition of states, and does not really fly away from a point such as shown in the above drawing. Instead, imagine a spherical shell, expanding away from the point of origin in every direction. This is analogous to dropping a rock in water and watching the ripples spread out in a circular pattern. We don't say the water is suddenly accelerated away from the point of impact at some velocity. Its the waves that are doing this. The molecules of water aren't really moving horizontally much at all, they mostly move up and back down as the wave passes.

This is not to say a photon is a disturbance in some media, since as far as anyone has proven, there is no media through which the wave travels.

The photon only becomes a point like particle when it interacts with something else.

It is an interesting subject..... yes?

From a laymans point of view we have a photon or wave that is travelling at 299792kms per sec.

From a stationary starting point or point of origin. The wave or photon some how has to get to this speed or velocity from relatively zero velocity.

To do this it wave or particle would have to go through an acceleration phase.
But,
If light is invariant in velocity then this suggests that there is no acceleration and that the wave of particle some how starts from 299972 kms per second. And this is central to my question.

Even if we are talking about a wave how does it achieve 299972kms per second with out acceleration from zero?

When light enters a material, photons are absorbed by the atoms in that material, increasing the energy of the atom. The atom will then lose energy after some tiny fraction of time, emitting a photon in the process. This photon, which is identical to the first, travels at the speed of light until it is absorbed by another atom and the process repeats. The delay between the time that the atom absorbs the photon and the excited atom releases as photon causes it to appear that light is slowing down. http://www.physlink.com/Education/AskExperts/ae509.cfm

It can be justified if mirror or reflecting material got effected/heated or degraded by photons exposed to it.

I am sorry it still doesn't explain the acceleration to 'c'....even if absorbtion casues the atom to change it still has to release a photon or wave and in doing so it woul dbe intuitive to expect an accelleration phase.....wouldn't it?
The phase may be miniscule but it must exist.......that is of course if light has to travel in the first place.

On second thought, I might bet large sums on my opinions. How could those opinions be proven wrong in my lifetime? It would be very difficult to tag a photon approaching a mirror and record that the reflected photon had the same identifying tag. Assuming that it was created with no velocity, what sort of apparatus could measure the acceleration of a newly created photon?

Dinasaur, If I was into losing money I would take you up on that bet..ha...
but my money is on that fact that a photon doesn't exist as a wave or particle.....but again it might take a while for me to collect on it.... :)

The point of origin of the photon and how it manages to go from a relative zero velocity to 299792kmps and yet maintainit's invariance.
If 'anything' has to be called a photon, it should have a constant velocity 'c' (in vacuum) from its beggining to its end. So, if 'anything' accelerates from 0 to c, it cannot be called photon then, because photon cannot have a velocity other than c (in vacuum). Its better not to contemplate on its acceleration phase, photon may get angry. :D

Yes, to put it another way, the photon never exists at velocity zero, consequently there is no need for an acceleration phase. In any case if photons accelerated, where would the energy (impulse) come from to impart the velocity to them?

Photons are emitted when subatomic particles jump from one energy level to another. There is no intermediate energy level or "motion" through an infinite number of intermediate energy points. It was because of the original assumption that all energy levels existed which led to all interactions coming out with infinite energy levels which led Planck to formulate his quantum theory in the first place. And then he only thought of the quantum as a mathematical trick. Consider that the energy level is discrete, that it can only hold specific values set apart by irreducible intervals. Now reduce the interval to zero. Unfortunately when he reduced the interval to zero he got infinite energy levels again. Only when the interval was a specific value did the mathematics match the outcome, and thus: Planck's Constant, h.

I thought that as the sun churns internally its magnetic core accelerates those particles up and down until they reach a velocity that lets them escape from that magnetic trap. Is this a possibility or am I way off ?

Which particles are you referring to? Photons don't need to reach a velocity in order to escape the sun, what happens is that the equivalent of "a photon" is generated at the heart of the sun, moves at the speed of light, but is immediately absorbed by a nearby hydrogen molecule, then re-emitted. A (so-called) single photon being constantly absorbed and re-emitted can ultimately make its way to the surface of the sun where it no longer encounters matter to absorb it (until it hits your eye on the Earth eight minutes later), but the process of getting there can take an estimated one million years.

Which particles are you referring to? Photons don't need to reach a velocity in order to escape the sun, what happens is that the equivalent of "a photon" is generated at the heart of the sun, moves at the speed of light, but is immediately absorbed by a nearby hydrogen molecule, then re-emitted. A (so-called) single photon being constantly absorbed and re-emitted can ultimately make its way to the surface of the sun where it no longer encounters matter to absorb it (until it hits your eye on the Earth eight minutes later), but the process of getting there can take an estimated one million years. What do you mean by "equivalent of "a photon"? Do you mean same photon as absorbed is re-emitted or a differant photon of exactly same value/strength is re-emitted? How it can be exactly same photon in value/strenght, does it not leave/loose any trace or effect on travel throgh hydrogen molecule/atom/s?

Quantum Quack,

I personally believe that photons are emitted at speeds much lower than c, but are accelerated to c by external gravitational fields.

To assume that a particle at rest, like an electron, can produce another particle that travels at c, without that second particle having to accelerate from 0 to c, is not only counterintuitive, but illogical as well. So if you believe in Relativity, you must believe in instantaneous acceleration.

just curious, when we think of a photon do we think of a spherical shaped massless particle? Or is it some other shape?

Quantum entities cannot be visualized. There is no model of them which makes sense.

Photons have wave-like properties and they have particle-like properties. Somebody once said that they depart and arrive as particles, but travel as waves. Much the same can be said for electrons and other quantum objects. Even atoms seem to sometimes have wave-like properties.

Do not rely on your intuition when thinking about quantum objects.

"Even atoms seem to sometimes have wave-like properties"
Dinosaur,

It is said that every substance has come from some prime energy. Will then every substance possess/have somewhat energy/light or photons properties as waves.

My advice: the one, who really wants know what photon can be in Nature, what space-time structure it, may be, has and how it can be created and propagate should read "The Scientific Notes" vol. #8 on www.minescience.com (http://www.minescience.com)