What is the speed of light in the reference frame of the photon?

[pavelcherepan]

It might be a very stupid question but in a sense of particle-wave duality if we take a reference frame of a photon what would be the speed of the wave represented by that same photon in this particular reference frame?

 

 

[J.C.MacSwell]

It might be a very stupid question but in a sense of particle-wave duality if we take a reference frame of a photon what would be the speed of the wave represented by that same photon in this particular reference frame?

 

 

I don't believe the reference frame of a photon has ever been defined, at least in any accepted form.

[Strange]

It doesn't make any difference whether you consider light as a wave or a photon; they both travel at the speed of light. This cannot be a frame of reference because treating as such causes division by zero and the sort of contradiction you mention (how can light travel at the speed of light relative to light).

[Nicholas Kang]

The speed of light is constant and it is a very specific reference frame.

[Strange]

The speed of light is constant and it is a very specific reference frame.

 

No, the whole point is that it isn't a valid reference frame.

[Nicholas Kang]

Ok, why it isn`t a valid reference frame?

[swansont]

Ok, why it isn`t a valid reference frame?

 

We have no physics to describe what goes on at v=c; all of the equations diverge.

[Strange]

Ok, why it isn`t a valid reference frame?

 

To expand on what I said above, if you try and apply the formulas for converting from one frame to another, you end dividing by zero. The reason is that the Lorentz factor is defined as [latex]\gamma = \frac{1}{\sqrt{1 - v^2/c^2}}[/latex]. If you make v = c, then you have [latex]\gamma = \frac{1}{0}[/latex].

[pzkpfw]

This may not be what the OP is getting at, but I have seen people imagine a wave as being a little "particle" that goes up and down as it moves along. So they think if the "particle" is moving along at c, and going up and down, then it's overall speed must be more than c.

 

But it isn't, so it doesn't.

 

And this may all be irrelevant to this thread, so in case - sorry.

[hoola]

is the speed of light continuous? If light is a continuing conversion of the electic field to magnetic, then back again, is the speed that it travels as an electric field equal to the speed it travels as a magnetic? And, is there a variation in the speed as the photon is in transition between the two states? I would presume a fine gradient of variation occurs, even in a perfect vaccuum...would virtual particles be of any consequence to a ray of light in empty space?

Edited July 10, 2014 by hoola

[xyzt]

is the speed of light continuous? And, is there a variation in the speed as the photon is in transition between the two states?

Yes

 

 

If light is a continuing conversion of the electic field to magnetic, then back again, is the speed that it travels as an electric field equal to the speed it travels as a magnetic?

Light is Electro-Magnetic waves, as such, it Always travels at c, as evidenced by the E-M wave equation.

 

 

I would presume a fine gradient of variation occurs, even in a perfect vaccuum...

No.

[hoola]

It seems that 4 determinants might control the consistency of the speed of light in a vaccuum. The transitioning from electric to magnetic fields, the reversal of that process (which may not be symmetric), and two different speeds of the respective fields as they propagate through space...

[md65536]

Ok, why it isn`t a valid reference frame?

In addition to the equations not making sense, they are consistent with everything else that's known about photons, and there is no way in which such a reference frame makes physical sense.

 

Think of what it means to have an observational frame of reference, and I suspect that anything you think of will not apply to a photon.

 

All lengths contract to zero in the direction of travel, so they can't measure length. All trips would take zero time, so there is no way to measure travel time. A photon's state doesn't change from emission to absorption, ie. it doesn't age, ie. it measures no passage of time. A photon doesn't absorb other photons, so it can't observe anything while traveling. To accelerate to c requires infinite energy, unless you have no mass, but if you have no mass then you have no rest energy, so you can't be at rest and you can't have a rest frame. All these things fit together, and there's nothing that describes a photon being able to observe. The math models physical reality, and the math doesn't work for a photon's frame of reference, while there is also no such thing known or theoretical that makes sense to model.

Edited July 11, 2014 by md65536

[robinpike]

In addition to the equations not making sense, they are consistent with everything else that's known about photons, and there is no way in which such a reference frame makes physical sense.

 

Think of what it means to have an observational frame of reference, and I suspect that anything you think of will not apply to a photon.

 

All lengths contract to zero in the direction of travel, so they can't measure length. All trips would take zero time, so there is no way to measure travel time. A photon's state doesn't change from emission to absorption, ie. it doesn't age, ie. it measures no passage of time. A photon doesn't absorb other photons, so it can't observe anything while traveling. To accelerate to c requires infinite energy, unless you have no mass, but if you have no mass then you have no rest energy, so you can't be at rest and you can't have a rest frame. All these things fit together, and there's nothing that describes a photon being able to observe. The math models physical reality, and the math doesn't work for a photon's frame of reference, while there is also no such thing known or theoretical that makes sense to model.

 

But this assumes that light and matter are fundamentally the same...

 

Yes, all the above probably does apply to matter - but why does it have to apply to photons?

[Strange]

 

Yes, all the above probably does apply to matter - but why does it have to apply to photons?

 

The point is that it doesn't apply to photons: there is no valid frame of reference for photons (*) so you cannot, even in principle, say what happens from a photon's "point of view".

 

(*) Because you end up dividing by zero.

[Nicholas Kang]

So, we need new physics. Who is going to develop them? Maybe I am interested in it?

 

My ambition is to be a scientist.

[Strange]

So, we need new physics.

 

I don't think we need new physics to address anything discussed in this thread. This is all well understood and tested.

 

There are, of course, plenty of other areas where we do need new physics. So good luck with your ambition! Maybe you will be one of those who helps develop the next new theory.

[Nicholas Kang]

Ah?! Why we don`t need new Physics? I thought scientists will face problems when dealing with faster-than-light speed calculations in theoretical physics.

[Strange]

Ah?! Why we don`t need new Physics? I thought scientists will face problems when dealing with faster-than-light speed calculations in theoretical physics.

 

There is no problem dealing with the calculations. There are even hypothetical (i.e. nonexistent) particles called tachyons, based upon that mathematics. But the mathematics clearly tells us that (a) no massive object can move at the speed of light and (b) the speed of light is not a valid reference frame.

Edited July 11, 2014 by Strange

[Nicholas Kang]

Physics is restricted to Mathematics. Is it possible to go for faster-than-light travelling/moving? Or this is impossble because Maths again?

 

I understand statement b) but still suspicious towards statement a)

[Strange]

It is not impossible *because* of mathematics; the mathematics just describes the physics that makes it impossible.

 

(Of course, it may be that a future theory shows us how it is possible, after all. But there is no point speculating about that.)

[Nicholas Kang]

Please clarify your statement. I am a bit confused. You mean that Mathematics can take over old Maths, so new Maths will replace the current assumed Maths formula and simply makes faster-than light-travel possible?

[Strange]

Please clarify your statement. I am a bit confused. You mean that Mathematics can take over old Maths, so new Maths will replace the current assumed Maths formula and simply makes faster-than light-travel possible?

 

No, not new maths. New physics. The theory of relativity (and its mathematical description) replaced Newtonian gravity (and its mathematical description).

 

Yes, the mathematics changes, but only because the theory changes. Maths doesn't make things happen (nor do theories) it just describes (and predicts) what can happen.

 

If faster than light travel is actually possible then one day we will have a new theory that describes (including the maths) how that works. On the other hand, we have no reason to think that it is possible and a good, well-tested theory that says it isn't.

[swansont]

Physics is restricted to Mathematics. Is it possible to go for faster-than-light travelling/moving? Or this is impossble because Maths again?

 

I understand statement b) but still suspicious towards statement a)

 

It's not possible because that's how nature behaves. It's predicted and confirmed by the mathematics, but we would toss these equations if they didn't accurately describe experiments and develop one that did the job.

[Nicholas Kang]

How can we know this is how nature behaves? We don`t create nature. We know them by exploring them, something like nature archaeologist. But when these eternal questions can be solved is something interesting. We can toss equations that well describe experiments but what about the origin of universe and the end of the universe? You can simply say we are stationary while standing, but the Earth is moving. YOU Assume the Earth is not moving, the Solar System is revolving around the Milky Way. Assume that the Solar System isn`t moving, the Milky Way galaxy is heading towards Andromeda M31 at 110km/second. Assume that galaxies, clusters and superclusters aren`t moving, but then space is expanding, thus eternal question.

 

Edit: I mean we simply say we are not moving when we stand on Earth but the Earth move. And you must take other factors into account, this includes The moving of solar system, Milky Way Galaxy, Local Cluster and the expansion of space itself.

Edited July 11, 2014 by Nicholas Kang