Is light time dilated?

[Singularitarian]

What the heck are you on about?

A photon from its point of view does not experience time pass at all. In fact, it does't even have a proper existence at all. It's death and birth are simultaneously the same thing. It's internal experience is stuck in null trajectories, making the time dilation infinitely-stretched.

The photon has what’s called a 4-momentum [latex]p^{\mu}[/latex] and a 3-momentum [latex]P_i[/latex]. The photon in relativity
is said to move along a null trajectory so [latex]p^{\mu}p_{\mu}=0[/latex], but in considering the energy, traditionally given as [latex]E[/latex] and the 3-momentum this is [latex]-E^2+|p|^2=0[/latex]. The path it moves through space from
an observers point of view is completely different to that of a photons however. In usual metric structures, you have [latex]p^{\mu}p_{\mu}=-M^2=+E^2-(p^1)^2+p^{2}_{j}[/latex] with a perpendicular component given as [latex]j[/latex] in
this case.

Only from our perspective can a photon be seen to move through time.

 

[Reality Check]

What the heck are you on about?

A photon from its point of view does not experience time pass at all. In fact, it does't even have a proper existence at all. It's death and birth are simultaneously the same thing. It's internal experience is stuck in null trajectories, making the time dilation infinitely-stretched.
...snipped random math...
Only from our perspective can a photon be seen to move through time.

What the heck are you on about?

The reason that I put "experience" in quotes is the obvious reason - a photon is not an observer and so it cannot experience time. Thus a photon has no point of view.

Now add an observer travelling with the photon. That observer does have a point of view. That observer experiences time passing as normal.

ETA
A photon also does not have a have a frame of reference as they are assigned by observers.

 

[Singularitarian]

It's classed as a subatomic observer, it's still an observer. Just like the electron is a observing system, capable of decohering due to defining attributes with other particles. Like a spin-spin relationship, for instance. It just so happens as well, that particles experience time. The electron is even found to possess an internal clock.

But for the photon, it cannot move through time, because the Dilation has been stretched into infinity.

 

[Singularitarian]

And its impossible for inertial mass, like myself to travel at that speed. I contain rest mass, so my observation is pointless to imagine.

 

[Reality Check]

I am not sure what you mean by the last couple of posts.
But maybe you are talking about real observers such as you or me who cannot be accelerated to the speed of light.
However the observers used in relativity are theoretical observers. Their only property is the ability to observe. They can travel at the speed of light.

Dialtion is an observed effect.
An observer observing a clock travelling at the speed of light would measure that the clock has stopped. An observer travelling with the clock looking at a clock with the first observer would measure that the clock has stopped.
Thus your "Dilation has been stretched into infinity" statement means that time does not exist for either observer.
One observer is you. The other observer is attached to a photon.
Has time stopped for you?

Or to put it another way: A photon from its point of view sees that Dilation has been stretched into infinity for you since you are travelling at the speed of light relative to it. You cannot travel through time.

 

[Singularitarian]

Look - a photon cannot experience time pass.

That's a mathematical certainty.

 

[Reality Check]

Look - a photon cannot experience time pass.

That's a mathematical certainty.

We agree - photon cannot experience time pass.

That's a physical certainty.

 

[edd]

Look - a photon cannot experience time pass.

That's a mathematical certainty.

How, then, can a photon have a frequency?

 

[Singularitarian]

For crying out loud.

I do wonder sometimes about this place.

Quoted from Gribbin´s "Schrodinger´s kittens":
The Lorentz transformations tell us that time stands still for an object moving at the speed of light. From the point of view of the photon, of course, it is everything else that is rushing past at the speed of light. And under such extreme conditions, the Lorentz-Fitzgerald contraction reduces the distances between all objects to zero. You can either say that time does not exists for an electromagnetic wave, so that it is everywhere along its path (everywhere in the Universe) at once; or you can say the distance does not exist for an electromagnetic wave, so that it "touches" everything in the Universe at once. ''

 

[sol invictus]

Quoted from Gribbin´s "Schrodinger´s kittens":
The Lorentz transformations tell us that time stands still for an object moving at the speed of light. From the point of view of the photon, of course, it is everything else that is rushing past at the speed of light. And under such extreme conditions, the Lorentz-Fitzgerald contraction reduces the distances between all objects to zero. You can either say that time does not exists for an electromagnetic wave, so that it is everywhere along its path (everywhere in the Universe) at once; or you can say the distance does not exist for an electromagnetic wave, so that it "touches" everything in the Universe at once. ''

Very strange, then, that (for example) the phase of a photon rotates as it travels, isn't it?

 

[Singularitarian]

Strange as well that we observe a photon moving 150,000,000 km from the sun, but it's frame dictates there is no space to travel through.

 

[ynot]

As I understand it . . .

“travelling” things always experience their own “proper time” regardless of their relative speed. In other words a thing never experiences it’s own time dilation. Time dilation is the slowed rate of the “proper time” of a “travelling” thing relative to the “proper time” of a “stationary” thing and time dilation is only evident as a comparison of both “proper times“.

Light therefore wouldn’t experience any time dilation of it’s own “proper time” but would be time dilated to the point of 0 time relative to the “proper time” of everything else.

I don’t understand how time dilation wouldn’t dilate the very relative speed that creates it. I also think that everything in the Universe is moving/travelling in an absolute sense and don’t see how any relative movement/travel can be correctly defined as being either faster or slower that any other relative movement/travel

 

[sol invictus]

I don’t understand how time dilation wouldn’t dilate the very relative speed that creates it.

It does, in a sense. For example, imagine a rocket accelerating at a constant rate in its own rest frame. To an observer, the apparent acceleration will get less and less as time passes and the rocket's speed approaches c.

Or is what you're confused about is some kind of infinite regression: velocity causes time dilation, but that reduces the velocity, which changes the time dilation, which changes the velocity... ?

If so, that's fully taken into account by the formula. It's like interest compounded continuously - there's interest on the interest on the interest ad infinitum, but the total is still finite, and we can write down a formula that takes all those corrections into account simultaneously. Math is powerful.

I also think that everything in the Universe is moving/travelling in an absolute sense and don’t see how any relative movement/travel can be correctly defined as being either faster or slower that any other relative movement/travel

I can't figure out what you're confused about there. If motion is absolute, there's no problem defining relative velocity - just subtract the two absolute velocities. If it's not (and it isn't) there's still no problem.

 

[Xulld]

infinitely dilated indeed.

Edit:

Also reading through these remember there is no ultimate frame of reference its always the observers frame, and light does not observe you, "dam light quit watching me at all stages of my life all at once dam you!"

 

[ynot]

infinitely dilated indeed.

Edit:

Also reading through these remember there is no ultimate frame of reference its always the observers frame, and light does not observe you, "dam light quit watching me at all stages of my life all at once dam you!"

So light is omnipresent all-seeing and all-knowing . . . Hmmmmmm.

 

[bobdroege7]

Isn't the speed of light a theoretical maximum anyway, and doesn't matter bend light in essence slowing it down, so as long as there is one electron and one photon in the universe, that photon is slowed by the electron, no matter how far away the electron is?

 

[ynot]

Given there is no universal/absolute stationary I don’t see how relative velocities can be applied to things other than being universally/absolutely equal and opposite. If A is moving at x relative to B then B is also moving at x relative to A. Relative motion is motion between things not of things. Periods of acceleration doesn’t establish that anything is moving universally/absolutely faster or slower than anything else. Any time dilation that applies to a thing should apply equally to all other things that it moves relative to.

 

[sol invictus]

Given there is no universal/absolute stationary I don’t see how relative velocities can be applied to things other than being universally/absolutely equal and opposite.

They aren't, so long as you're considering only two objects or reference frames. But it's sometimes necessary to consider more than two.

If A is moving at x relative to B then B is also moving at x relative to A.

You meant -x, but yes.

Relative motion is motion between things not of things.

Yes.

Periods of acceleration doesn’t establish that anything is moving universally/absolutely faster or slower than anything else.

Yes.

Any time dilation that applies to a thing should apply equally to all other things that it moves relative to.

That's not quite how it works. Time dilation is an effect measured by some observer. That observer doesn't notice any time dilation of herself - only of something moving relative to her. Of course that thing would measure an equivalent time dilation of her - is that what you mean? - because as you say, the relative velocity is equal and opposite.

As far as I can tell everything you said is more or less correct, but you still seem to be confused by something...

 

[Ziggurat]

But I’m talking about light being observed by a “stationary” observer that light is travelling relative to at c. How can anything be observed to be moving at c (or any speed) if time stops at c?

Let's take a step back. Special relativity is all about the space-time metric:
ds² = dx² + dy² + dz² - (c dt)²To transform from one inertial reference frame to another, we must preserve ds². The class of continuous transformations which do this are called Lorentz transformations. When we apply these transformations to an object, we can derive things like length contraction and time dilation, which are consequences of the Lorentz transformations. The Lorentz transformations are usually formulated in terms of a relative velocity between our initial reference frame and our final reference frame, and so are the length contraction and time dilation formulas. If we plug in c to our time dilation formula, it looks like time stops.

But we've actually skipped a step. What happens if we plug in c to our Lorentz transformations directly, and THEN see what we get? Well, we encounter a problem: if you try plugging in c for your relative velocities for the Lorentz transformations, you get a divide by zero. Which is undefined. So we cannot use the Lorentz transformations to change to a reference frame moving at the speed of light, and so the length contraction/time dilation equations derived from that are just not valid. Now, there are a number of ways of looking at that, but I think the simplest way to handle it is to simply conclude that a frame moving at c is not a valid inertial reference frame. This doesn't mean that nothing can move at c, it means that you cannot adopt it as a reference frame. So the question of what happens to time in the reference frame of the photon becomes meaningless.

 

[ynot]

They aren't, so long as you're considering only two objects or reference frames. But it's sometimes necessary to consider more than two.
You meant -x, but yes.
Yes.
Yes.
That's not quite how it works. Time dilation is an effect measured by some observer. That observer doesn't notice any time dilation of herself - only of something moving relative to her. Of course that thing would measure an equivalent time dilation of her - is that what you mean? - because as you say, the relative velocity is equal and opposite.

As far as I can tell everything you said is more or less correct, but you still seem to be confused by something...

Yes that is what I mean. But time dilation isn’t just an effect that is measured only by some single observer. If two observers are moving relative to each other they should both measure the same amount of time dilation of the other as you have agreed - “Of course that thing would measure an equivalent time dilation of her“. I can’t see that one observer might have undergone periods of accelerated to cause the relative movement is of any importance because as you have also agreed - “Periods of acceleration doesn’t establish that anything is moving universally/absolutely faster or slower than anything else”. I guess in my mind the only correct observation/measurement is a universal one that considers all observers simultaneously. This would create a paradox however with self-observed proper times conflicting with other-observed dilated times when they are in the same inertial frame.