What does light feel about its motion?

[Munim]

What is the nature of the motion of light with respect to itself? Does it experience time and displacement? 

[swansont]

Relativity doesn’t afford us the ability to say; light is not in an accessible frame of reference, so the transforms do not work. 

[MigL]

50 minutes ago, Munim said:

What is the nature of the motion of light with respect to itself

Without any reference, like air resistance, ir points passed, such as empty space, would you feel motion or displacement ?

I assume it feels a little stressed from the stress-energy-momentum tensor forcing it to change its path through curved space-time around massive bodies.
Bad pun ??

[exchemist]

1 hour ago, Munim said:

What is the nature of the motion of light with respect to itself? Does it experience time and displacement? 

In theory it does not experience time (time dilation -> ∞ as v -> c).

Absent any sense of time, it seems to me that "experience" has no meaning. 

Edited October 6 by exchemist

[swansont]

1 hour ago, exchemist said:

In theory it does not experience time (time dilation -> ∞ as v -> c).

Absent any sense of time, it seems to me that "experience" has no meaning. 

It’s undefined. You can’t use the Lorentz transform to shift between an inertial frame and that of a photon, and back.

[geordief]

1 hour ago, MigL said:

Without any reference, like air resistance, ir points passed, such as empty space, would you feel motion or displacement ?

I assume it feels a little stressed from the stress-energy-momentum tensor forcing it to change its path through curved space-time around massive bodies.
Bad pun ??

Would  it rather see the world moving (jiggling) and itself just traveling in a "straight  line"?

Would it experience the alternating magnetic/electric fields or do they disappear  in its "own frame"?

[swansont]

2 hours ago, geordief said:

Would  it rather see the world moving (jiggling) and itself just traveling in a "straight  line"?

Why jiggling? (The sinusoidal depictions of E & M fields are the field strength, not their trajectory, if that’s what this is a reference to)

[geordief]

43 minutes ago, swansont said:

Why jiggling? (The sinusoidal depictions of E & M fields are the field strength, not their trajectory, if that’s what this is a reference to)

No it wasn't (but I am under no illusion as to how nonsensical  my notion is)

The jiggling  was  me imagining the whole universe moving left/right /up/down as the light was the only actor moving in a straight line  .(is that a bit reminiscent of the  world spinning around the famous ,presumably stationary  bucket of water?)

The e/m fields  observation was an afterthought -or a second thought as to how they would seeem to the photon itself (wouldn't exist?)

ps yes  I think I understood that  they were field strengths  and not trajectories but  would they exist for the photon?

If there is no valid frame of reference for the photon does that mean we can't ask any questions  as to what is going on there even if they seem ridiculous?

 

 

 

[MigL]

In empty space, a photon would not know it is moving, as it is moving at constant velocity, and there are no reference points for it to discern its velocity or distance travelled.
Further, it would need to interact with any reference point, so it needn't be totally empty space

[swansont]

5 minutes ago, geordief said:

ps yes  I think I understood that  they were field strengths  and not trajectories but  would they exist for the photon?

Yes. It’s still EM radiation.

5 minutes ago, geordief said:

If there is no valid frame of reference for the photon does that mean we can't ask any questions  as to what is going on there even if they seem ridiculous?

We can answer questions based on observations from valid reference frames, i.e. ones an observer (with mass) can be in.

[Mordred]

It gets worse than that as ds^2=0 for null geodesics which is another reason for a photon frame being invalid as a reference frame. Its nonsensical answers such as time stopping or the photon existing everywhere at once that makes it obvious on the photon  frames invalidity.

[MigL]

True.
But we can attempt to 'see' what happens to the frames around the photon.
As Einstein did when he imagined travelling along with one, to arrive at SR.

[Harrot]

9 hours ago, MigL said:

True.
But we can attempt to 'see' what happens to the frames around the photon.
As Einstein did when he imagined travelling along with one, to arrive at SR.

That's some other odd thing with SR. Einstein tried to figure out what it would look like for someone riding a photon like a horse. This leed him to invent SR and then SR states that this is not even possible to think that way. This is quantum thinking : Here we got the link we are searching along between quantum physic and relativity ! Thats a [true - not true] state !

Something we know since around 1931 is : Photon has spin 1

https://www.nature.com/articles/128870a0

Consequently, we can't say that the photon doesn't experience time itself.

Of course, to say whether something is experiencing time or not, we'd have to define what time is. As this point is unresolved, or better still, can be defined in (too) many ways, there is no clear answer. Local time, or relative time, the many possibilities even make the question unclear.

For some, time IS the change of something, so if nothing “happens”, the thing we call “time”, because it's equivalent here to the thing “something is different when we measure it twice”, is not time in an "experience" point of view. We can even say that the difference between two states of “IT” can be expressed by a kind of energy, “action”. This is a coherent point of view: there's action, so there's change, so there's time.

Here, I often hear it said: photons can't be measured twice! The concept of time is therefore unsuitable for photons, because interaction with a photon destroys it. This is not true: you can measure the effect when it appears (the movement of the atom that emitted it) AND you can measure the effect when it disappears. So if you consider “IT” as the whole: “IT” interacting twice with the environment by exchange of action, IT.... is experiencing time.

 

Of course, if you think of “IT” as the thing that contains quanta... as soon as “IT” interacts, “IT” is no more. So what's left is the wave between the events that appear and disappear, with a virtual photon that nobody can prove exists. I think this is interesting; it behaves as if, when we exclude creation and destruction as part of the photon, the photon seen as a wave (EM intensity changes during... time) reminds us that the photon experiences time, relative to the external environment.

We must therefore consider 2 types of “IT” thing, that of particles, and that of waves.

A : The particle one says that there is a creation and destruction event of the "IT" particle (relative to the environment) that should allows us to consider that the photon is  experiencing time (seen as a change in the thing “IT”).

B : The wave one says that there is a change of the “IT” wave within the trajectory (relative to the environment), the definition of “IT” excluding creation and destruction as part of “IT”.

C : The theory of the wave and the particle says that the photon “is” the thing that begins as a particle when it is created, behaves as a wave when it moves and ends as a particle. This speculation doesn't allow us to draw simple conclusions. In this case, perhaps we should consider “the photon thing” as something that doesn't exist without the presence of the environment. Which is to say that every property in physics (and therefore even presence... which is considered in contrary real without interaction, as we see in mainframe physics), is the conjunction of an interaction. In this particular point of view, perhaps photon doesent experiment time, because there could be virtual photons, so change without time.

 

Edited October 7 by Harrot

[swansont]

20 minutes ago, Harrot said:

“something is different when we measure it twice”,

This doesn't work when you measure something cyclical, because it can be the same even though time has passed. In fact, lots of things can be the same even though time has passed. Even if you use radioactive decay; time passes and yet the nucleus can be the same.

But this, and the rest, are not considering light "with respect to itself" as is asked in the OP. They are from the view of an observer, which is not traveling at c. 

[geordief]

Does the photon only "know" that the electric and the magnetic fields **  are interacting? (is that actually what the photon "is"?)

 

Does that pass for change in its world?

 

What can happen for the photon for this process itself to change? (can  the photon "die"?) 

**is it important to distinguish between a "field as a set of measurements" and a field as a fundamental bedrock of nature? Are  the two fields making up the photon's existence part of the wider universal  electric and magnetic fields?

[timothy123]

On 10/7/2024 at 12:50 AM, exchemist said:

In theory it does not experience time (time dilation -> ∞ as v -> c).

Absent any sense of time, it seems to me that "experience" has no meaning. 

Yes it may be on experience base.