How photons lose energy.

[Incendia]

Well...I was thinking about energy...If photons are a form of energy [electromagnetic energy] and they never stop moving then shouldn't they lose energy to motion?

That is my speculation...That if photons are energy they convert into kinetic energy...hopefully that makes sense...

It's common sense really...it's just I haven't found any sources that tell me photons lose energy due to their motion...although as far as I know it is a perfectly logical conclusion.

Have I stumbled upon something new or has this already been thought of?...or dis-proved?...

Edited December 12, 2010 by ProcuratorIncendia

[Sisyphus]

Things don't lose energy just from moving, though.

[Incendia]

Yes they do...they convert energy into kinetic energy...we move and we convert chemical energy into kinetic energy which we lose.

[timo]

I think the ancient Greeks thought that a body's natural state was being at rest and that keeping in motion did require energy. It is generally attributed to Newton (again, if I recall that correctly) to realize that this is not true and that the natural state of an object is to keep moving at the current velocity unless somehow affected from the outside. So to answer your question: it has been thought of (by the ancient Greeks). It is generally considered not being the case since Newton (~300 years).

 

Incidently, the idea that nature could be understood by rational thinking alone was also the Greek's attitude, I think, and the attitude that ideas alone are insufficient and should be tested in experiments is rather new (though possibly slightly older than 300 years).

[Incendia]

I don't understand...why is this wrong? I said I was wrong without saying why...

[Sisyphus]

I already said why it was wrong. Your unstated premise, that things lose energy just from moving, is not correct. There is no such thing as "losing energy to motion."

[Incendia]

I didn't mean the energy is lost...I explained...the photon itself 'loses' energy as it moves because it cannot just conjure up kinetic energy that it needs for motion from nowhere. The photon itself converts into kinetic energy because as I understand it photons are made of energy.

 

*Refined OP*

Edited December 12, 2010 by ProcuratorIncendia

[Sisyphus]

It does not "need" a continuous input of energy to keep moving. That's what I'm trying to say. (Also, photons are not "made of" energy, but that's less immediately important.)

[lemur]

I didn't mean the energy is lost...I explained...the photon itself 'loses' energy as it moves because it cannot just conjure up kinetic energy that it needs for motion from nowhere. The photon itself converts into kinetic energy because as I understand it photons are made of energy.

This is an issue I've been thinking about a lot lately. I don't think it makes sense to think of photons in the same sense as particles with mass because mass allows particles to lose speed as they transfer momentum to other particles during collisions. Photons are emitted and absorbed and that's it, as far as I know. They can't hit an electron and transfer some momentum and then deflect off at an angle with less momentum. When they reflect, refract, or diffract, etc. they don't lose speed. Do they lose energy by their frequency decreasing from collisions? I don't know.

 

Personally, I think it makes more sense to think of radiation as a moving contraction of a field (either gravity-field, EM-field, or the intersection of the two). In that sense, light/radiation would not so much be a distinct/isolated particle in space as it would be a warping of the field it is traveling through. I don't know if this idea has already been explored and dealt with but it seems logical to me. So, basically, light/radiation would be a intra-(gravitational)field transfer of electron momentum across distance.

 

 

[Incendia]

It does not "need" a continuous input of energy to keep moving. That's what I'm trying to say. (Also, photons are not "made of" energy, but that's less immediately important.)

 

I'd say it is important...If I knew that they didn't need a continuous input of energy and why then this would be dis-proved...

[Mr Skeptic]

Hm, maybe you might be onto something. The photons don't lose energy just from moving, but in certain cases moving through matter can lower their energy. See Compton scattering. That's for very high energy photons, but what if the effect is also present for lower energy photons?

[DimaMazin]

I'd say it is important...If I knew that they didn't need a continuous input of energy and why then this would be dis-proved...

If space creates a resistance to moving, then local time of this space adds an energy.

[uncool]

Objects that are moving don't lose energy to kinetic energy. The fact that they are moving is the same as the fact that they have kinetic energy (in this frame).

 

Basically, an object that is moving has kinetic energy. It does not lose energy to kinetic energy. Period.

=Uncool-

[Incendia]

Light is not an object...it has no mass...It is made of energy...

[swansont]

I didn't mean the energy is lost...I explained...the photon itself 'loses' energy as it moves because it cannot just conjure up kinetic energy that it needs for motion from nowhere. The photon itself converts into kinetic energy because as I understand it photons are made of energy.

 

 

No, they are not made of energy. They have energy, which is kinetic energy. If they are to lose any it must be via some interaction, just as any other body loses energy via an interaction.

[John Cuthber]

ProcuratorIncendia,

Imagine a single photon travelling through empty space.

If it "loses energy" as you say then what does it transfer that energy to?

If there is no transfer of energy to something else, but the photon loses energy then that is a clear break in the law of conservation of energy.

 

Why do you think something needs to expend energy just to keep moving?

Even worse, imaging I look at a rock as I walk past. From my point of view it is moving. If you are right then, in order to be moving it has to expend energy.

The problem is that, in the same way, when I go for a walk every object in the universe has to expend energy to move (from my point of view)

How can that happen?

Edited December 12, 2010 by swansont
double post; deleted repeated text

[timo]

ProcuratorIncendia,

Imagine a single photon travelling through empty space.

If it "loses energy" as you say then what does it transfer that energy to?

If there is no transfer of energy to something else, but the photon loses energy then that is a clear break in the law of conservation of energy.

Perhaps that's never been thought of before!

[lemur]

Perhaps that's never been thought of before!

Perhaps what's never been thought of before? What does it matter whether it's been thought before or not? If it has and it was discarded as irrelevant, then no one remembers it. If it was validated as relevant, someone will recognize it from their personal genealogy of knowledge. When it was thought of is less relevant that whether there is validity in it.