If a photon is travelling at the speed of light, does time not exist for it?

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Offline CD13

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I'm a biological scientist, so excuse the basic nature of these questions:

As a photon travels at the speed of light in a vacuum, time must be non-existent then, surely? Thus it has no past or future, only the present?

If a photon slows when it goes through a material, where does the lost energy go? And when it speeds up, where does the extra energy come from?

Do tachyons exist? If so, how could they be detected?

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Offline yor_on

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A photon have no other 'speed' than light. That's why I wonder, just like you I guess:) What they really are. And they do exchange 'energy' when getting annihilated, and momentum too. So in a piece of matter they get 'slowed down' due to their 'annihilation' and subsequent 'resurrection' inside the matter. As for where the 'lost energy' goes? Depends on what you think 'energy' consists of.

Myself I do trust in a universe of equilibrium. That means that whatever happens inside it doesn't really take anything 'away'. So in that motto there is no 'energy' lost, only a 'interaction' taking part expressing itself into a transformation, or several rather when discussing that photon 'propagating'.
« Last Edit: 21/01/2011 16:31:09 by yor_on »
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Offline Ron Hughes

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From the photon's frame of reference, when it is created at A it instantly appears at B no matter how far away from A. See,  http://www.thenakedscientists.com/forum/index.php?topic=34333.0;topicseen
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Offline yor_on

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Hmm, time and photons :)
Should have answered that one too.

Nope, time don't exist for a photon, as far as we know. If it did you could expect them to die of 'exhaustion', well, sort of, getting old and all that. And that's the standard explanation to their timelessness. But there are some non-mainstream ideas in where they do have a 'clock' of some kind.

But as 'time' is a highly subjective matter according to the theory of relativity, changing whenever you look away from your own 'frame of reference' it makes sense. Why not, if time are mutable with speed? Why shouldn't a photon be 'time-less'? After all, nothing goes faster, that we have measured.
==

If we would assume a piece of matter near light speed instead it would never become 'time-less'. On the other tentacle it would never reach lights speed in a vacuum either.
« Last Edit: 21/01/2011 20:08:53 by yor_on »
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Offline Bill S

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Quote from: CD13
I'm a biological scientist, so excuse the basic nature of these questions:

I'm a non-scientist, so my comments are likely to be even more basic than your questions.

As RH points out, it is only in the F of R of the photon that time does not exist.  This seems to apply only to when the photon is travelling in a vacuum, but I find myself wondering if it also applies when it is passing through a medium in which we perceive its speed to be lower.  Is it travelling more slowly, only in the observer's F of R?

Tachyons, as far as I am aware, are theoretical particles, so no one knows if they exist.  Personally, I think that if they do exist this would imply the presence of a mirror universe.  That's probably material for another thread, though.  It's also probably rubbish.

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Offline JP

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Quote from: CD13
I'm a biological scientist, so excuse the basic nature of these questions:
As RH points out, it is only in the F of R of the photon that time does not exist. 

The problem is that in physics, there is no theory that defines the frame of reference of a photon.  This mistake is generally made because special relativity tells us that objects with mass have inertial reference frames in which a faster-moving object's clock will run slower than a slower-moving object.  If you naively, set the speed of a massive object to the speed of light, you find that it's clock stops.

The problem is that special relativity is derived only for objects with mass, and not for photons.  One of the postulates (that the speed of light is constant in all reference frames described by the theory) doesn't hold if you set the speed of the object to the speed of light.  Objects with mass can also never move at the speed of light, since that requires infinite energy.  So this is never a problem for them. 

So in summary, there is no theory for a frame of reference for a photon.  Saying they don't experience time is a common mistake made about special relativity.

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Offline QuantumClue

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Quote from: CD13
I'm a biological scientist, so excuse the basic nature of these questions:
As RH points out, it is only in the F of R of the photon that time does not exist. 

The problem is that in physics, there is no theory that defines the frame of reference of a photon.  This mistake is generally made because special relativity tells us that objects with mass have inertial reference frames in which a faster-moving object's clock will run slower than a slower-moving object.  If you naively, set the speed of a massive object to the speed of light, you find that it's clock stops.

The problem is that special relativity is derived only for objects with mass, and not for photons.  One of the postulates (that the speed of light is constant in all reference frames described by the theory) doesn't hold if you set the speed of the object to the speed of light.  Objects with mass can also never move at the speed of light, since that requires infinite energy.  So this is never a problem for them. 

So in summary, there is no theory for a frame of reference for a photon.  Saying they don't experience time is a common mistake made about special relativity.

Indeed.

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Offline Geezer

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The problem is that in physics, there is no theory that defines the frame of reference of a photon.  This mistake is generally made because special relativity tells us that objects with mass have inertial reference frames in which a faster-moving object's clock will run slower than a slower-moving object.  If you naively, set the speed of a massive object to the speed of light, you find that it's clock stops.

The problem is that special relativity is derived only for objects with mass, and not for photons.  One of the postulates (that the speed of light is constant in all reference frames described by the theory) doesn't hold if you set the speed of the object to the speed of light.  Objects with mass can also never move at the speed of light, since that requires infinite energy.  So this is never a problem for them. 

So in summary, there is no theory for a frame of reference for a photon.  Saying they don't experience time is a common mistake made about special relativity.

But if all matter is made of photons, then all matter can travel at c.
There ain'ta no sanity clause, and there ain'ta no centrifugal force æther.

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Offline QuantumClue

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The problem is that in physics, there is no theory that defines the frame of reference of a photon.  This mistake is generally made because special relativity tells us that objects with mass have inertial reference frames in which a faster-moving object's clock will run slower than a slower-moving object.  If you naively, set the speed of a massive object to the speed of light, you find that it's clock stops.

The problem is that special relativity is derived only for objects with mass, and not for photons.  One of the postulates (that the speed of light is constant in all reference frames described by the theory) doesn't hold if you set the speed of the object to the speed of light.  Objects with mass can also never move at the speed of light, since that requires infinite energy.  So this is never a problem for them. 

So in summary, there is no theory for a frame of reference for a photon.  Saying they don't experience time is a common mistake made about special relativity.

But if all matter is made of photons, then all matter can travel at c.

That is absurd. Who said matter would travel at lightspeed?

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Offline QuantumClue

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Matter is a concentrated energy. If you like, radiation is a free energy - a diffused type of matter. If all matter is made from photon energy, then it contributes to the kinetic energy of the system, and the inertial energy of the system. It does not mean that matter will move at lightspeed. This is in direct contradiction of relativity theory.

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Offline Geezer

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Matter is a concentrated energy. If you like, radiation is a free energy - a diffused type of matter. If all matter is made from photon energy, then it contributes to the kinetic energy of the system, and the inertial energy of the system. It does not mean that matter will move at lightspeed. This is in direct contradiction of relativity theory.

Are you saying that matter and photons are actually two totally different things? I thought you maintained that matter was made from photons, or did I get that wrong?
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Offline QuantumClue

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I'm a biological scientist, so excuse the basic nature of these questions:

As a photon travels at the speed of light in a vacuum, time must be non-existent then, surely? Thus it has no past or future, only the present?

If a photon slows when it goes through a material, where does the lost energy go? And when it speeds up, where does the extra energy come from?

Do tachyons exist? If so, how could they be detected?

Sure, by past and present, we mean the past cone and future cone of time. A photon has none of that. It follows a null trajectory. By theory, if it does not travel through time, it surely does not travel through space. Strange how we can measure such a thing, but as soon as we apply theory to the photon, it is not allowed to posses the asbtraction called a frame of reference. Time, space existence if you will, is all contracted out of its reality. Not a single second passes for the photon, nor does it take time to go anywhere.

As for tachyons, we do not believe they exist. Tachyonic Condensation, a mathematical work seems to exclude their existences altogether. However, if they did exist, we would look for Cherenkov Radiation in order to detect them. Such radiation can already be observed.

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Offline QuantumClue

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Matter is a concentrated energy. If you like, radiation is a free energy - a diffused type of matter. If all matter is made from photon energy, then it contributes to the kinetic energy of the system, and the inertial energy of the system. It does not mean that matter will move at lightspeed. This is in direct contradiction of relativity theory.

Are you saying that matter and photons are actually two totally different things? I thought you maintained that matter was made from photons, or did I get that wrong?

Yes you are wrong, again.

Matter can be made out of photons, it does not necesserily mean that attributes of the photon are carried on. Intrinsic properties in the form of information is almost certainly passed on in order to conserve quantities like charge and spin. It does not mean that the manifestation (matter) obeys the rules which radiation does. Matter and energy are still quite different, even though they are interchangeable via E=Mc2.

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Offline CPT ArkAngel

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General relativity implies that photons travel in no time in their frame of reference but it seems that people never really took it seriously...

Any particle near a black hole cannot sustain the strong acceleration and will turn into 2 photons (going in opposite direction) that will gain relativistic kinetic energy due to the Doppler effect. But i think half of the photons created as such, will escape the black hole. The black hole will catch E = MC^2/2... For an external fixed referential frame, the photons escaping loose an energy equal to half the gain in kinetic energy of the former particle due to a Doppler red shift in the ascension of the gravitational field...

For an outside observer, the appearing mass M in E=MC^2 at the event horizon is not the relativistic mass, but truly the rest mass. A photon reaching the event horizon will collide with the black hole in a perfect elastic collision. The relativistic kinetic energy momentum gained from the gravitational field before the collision is reciprocal for both, the photon and the black hole... After the collision, the momenta totally cancel each other.
« Last Edit: 07/02/2011 04:27:22 by CPT ArkAngel »

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Offline Geezer

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Matter is a concentrated energy. If you like, radiation is a free energy - a diffused type of matter. If all matter is made from photon energy, then it contributes to the kinetic energy of the system, and the inertial energy of the system. It does not mean that matter will move at lightspeed. This is in direct contradiction of relativity theory.

Are you saying that matter and photons are actually two totally different things? I thought you maintained that matter was made from photons, or did I get that wrong?

Yes you are wrong, again.

Matter can be made out of photons, it does not necesserily mean that attributes of the photon are carried on. Intrinsic properties in the form of information is almost certainly passed on in order to conserve quantities like charge and spin. It does not mean that the manifestation (matter) obeys the rules which radiation does. Matter and energy are still quite different, even though they are interchangeable via E=Mc2.


I thought you said this:

"What terminology do I use which is misleading, if we both agree matter is made from a fundamental energy, most associated to photons..?"

Isn't associating photonic energy with matter about as meaningful as saying that all atoms are really just modified hydrogen atoms?
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Offline yor_on

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I don't know JP, sometimes I feel the best way is to just ignore them.
Holes, I say, holes in our reality :)

But yes, we can't assign a frame to them. Doesn't mean that it is wrong to speak about them as being 'timeless'. From our point of view they definitely have to have an incredibly slow metabolism, or no 'time' at all. And that is a valid point of view.
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Offline JP

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But yes, we can't assign a frame to them. Doesn't mean that it is wrong to speak about them as being 'timeless'. From our point of view they definitely have to have an incredibly slow metabolism, or no 'time' at all. And that is a valid point of view.

There are points of view and then there's points of view that are supported by science.  Without a scientific model that supports the view that photons experience no "time," it's not valid science to claim so.  We don't know how to describe the reference frame of a photon scientifically, so any claims about it not experiencing time in it's own reference frame aren't scientific.

Of course, if you're talking about a photon being "timeless" in other ways, and you define timeless so that it fits scientific models, then you're talking science!  For example, photons don't appear to decay, so they might be timeless in that sense.  (They can, however, transition briefly into virtual electron/positron pairs.) 

However, photons can certainly travel in time.  If you shoot a laser at the moon, the photons will arrive at the moon roughly 1 second after they leave your laser.  They've traveled 1 second forward in time.

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Offline yor_on

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Well, I talked about their decay, didn't I?
Saying that their metabolism had to be either terribly slow or, as from our viewpoint, non existent. And what that make them, to me that is :) Is 'time less'. If you know a better definition for what they are I'm interested. I don't know any better way to view them :) Well, that should be as 'holes' then but, if so, we will wander of all mainstream definitions.

They are phreaky buggers, ain't they :)
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Offline CPT ArkAngel

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It is not scientific to dismiss a logical possibility and it is even more so if it answers many unsolved problems in a very simple way... Why to be afraid of simplicity...?

No mathematical expression represent reality in an absolute manner... General solutions hide concepts, specific solutions clarify them. Then you may use your imagination to get new solutions. If i had not found any truth, i would have chosen to write a book about it...
« Last Edit: 25/01/2011 23:02:44 by CPT ArkAngel »

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Offline Bill S

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Quote from: JP
in physics, there is no theory that defines the frame of reference of a photon

Quote from: JP
We don't know how to describe the reference frame of a photon scientifically, so any claims about it not experiencing time in it's own reference frame aren't scientific.

Looked at from a slightly different perspective; is there any scientific evidence suggesting that a photon's apparent experience of time exists other than in the F of R of an observer?

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Offline QuantumClue

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Quote from: JP
in physics, there is no theory that defines the frame of reference of a photon

Quote from: JP
We don't know how to describe the reference frame of a photon scientifically, so any claims about it not experiencing time in it's own reference frame aren't scientific.

Looked at from a slightly different perspective; is there any scientific evidence suggesting that a photon's apparent experience of time exists other than in the F of R of an observer?

I'll answer this. The answer is no.

If a photon decayed spontaneously in space, there might be some indication that it experiences a time, but this is not the case. Relative to us however, as JP has noted, photons do experience time.

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Offline Bill S

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Quote from: QC
Relative to us however, as JP has noted, photons do experience time.

Is that the same as saying that from the F of R of an observer, a photon experiences time?

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Offline CPT ArkAngel

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Photons interactions appear in time for matter but they have no timerate according to themselves.

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Offline Bill S

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QC, can you clarify this , please?

You say: of the photon "if it does not travel through time, it surely does not travel through space", and: "Not a single second passes for the photon, nor does it take time to go anywhere."

Taken together, these two statements seem to say that a photon does not travel through space.

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Offline JP

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Quote from: QC
Relative to us however, as JP has noted, photons do experience time.

Is that the same as saying that from the F of R of an observer, a photon experiences time?

The word "experience" brings with it a lot of connotations that muddies the picture a bit, as photons, not being conscious, don't experience anything as we humans do (or aliens in Geezer's case).  Could you define more rigorously what you mean by "experiencing time"?

Alternatively, I can ask you a simple question:
A photon is emitted by the sun at time t=0 and is absorbed by your eye at time t=8 minutes.  Is this "experiencing time"?

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Offline CPT ArkAngel

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it is 8 minutes for matter at no relative speed from the earth and the sun, certainly not for the photons...

I think what QC meant is that you cannot separate time and space. But it is theoretical.

According to Kaluza-Klein Theory, the charge is a fifth dimension. If the photons are made of charges (but having a total of zero), time and gravity could be an effect of the charges going at a slower speed than the speed of light... And it would generate relativity... Because all particles have charges, even the neutron. So all particles would have its own referential clock associated to its charge.
« Last Edit: 27/01/2011 00:51:37 by CPT ArkAngel »

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Offline Geezer

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Well, during my extensive intergalactic travels, I've yet to see a photon transmogrify itself into something else. They don't seem to decay or nuthin, whereas, AFAIK, everything else does.

Ergo (that's Alienspeak for therefore) photons (if they exist at all) seem to be exempt from the ravages of time.
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Offline JP

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True, Geezer.  Not decaying is a specific requirement as opposed to "not experiencing" time.  Photons clearly still move through time in all Einsteinian reference frames. 

By the way, the usual argument goes that photons are massless, so they move at the speed of light, and therefore they don't experience time.  To complicate matters, gluons are theoretically massless, but they lack the stability of photons: they hate existing in isolation.  Does this mean they don't experience time?

I think this is another case, as happens so often in science, where precise language is important, as is being very precise about what claims science can make about photons and what claims are philosophy.  (Thinking about the way a photon sees the universe from it's point of view is an exercise in imagination, not science!)

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Offline Geezer

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It's probably more philosophical that anything else, but I think energy does seem to "leak out" of everything over time, so one way to explain why that does not seem to happen in the case of photons is to exempt them from time.

Surely it's only important in the photon's frame of reference? How we perceive that "time" is not relevant.

We know that time "slows down" for things that travel fast. Why is it unreasonable to think that, at the extreme limit of speed, time essentially stops, or does not even exist.
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Offline CPT ArkAngel

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JP the Guardian of the Standard Model, you are very hard to convince but i must say you are often my first source of motivation to work and think harder about all this...

There is absolutely no proof that photons experience the passage of time. In fact, the mathematical equations of the Standard Model imply that photons have no timerate. In the contrary, Relativity as a whole would be crushed... I understand it is quite difficult to manage but it has to be this way if you look at the photons behaviour.

Geezer's arguments seem right to me.
« Last Edit: 27/01/2011 02:27:00 by CPT ArkAngel »

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Offline CPT ArkAngel

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General Relativity equations are not valid for sizes smaller than the Planck Length and it doesn't explain what happen to the electromagnetic and nuclear forces beyond that in a black hole... It just supposed to vanish... Because it is not tied up with Quantum Theory...

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Offline JP

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In fact, the mathematical equations of the Standard Model imply that photons have no timerate.

Really?  Can you give me an equation?

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Offline JP

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It's probably more philosophical that anything else, but I think energy does seem to "leak out" of everything over time, so one way to explain why that does not seem to happen in the case of photons is to exempt them from time.

But clearly that can't be true.  The fact that photons are absorbed and emitted shows that they aren't exempt from time.  They have to move through it! 

I do get the point about a photon's non-decay possibly being related to it's internal clock, but without a scientific model to describe that internal clock (and relativity ain't the way to do it!), is this a scientific question?  Would it be better to say "It doesn't decay" and be done with it?

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Offline Geezer

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It's probably more philosophical that anything else, but I think energy does seem to "leak out" of everything over time, so one way to explain why that does not seem to happen in the case of photons is to exempt them from time.

But clearly that can't be true.  The fact that photons are absorbed and emitted shows that they aren't exempt from time.  They have to move through it! 

I do get the point about a photon's non-decay possibly being related to it's internal clock, but without a scientific model to describe that internal clock (and relativity ain't the way to do it!), is this a scientific question?  Would it be better to say "It doesn't decay" and be done with it?

Yes. The process of creating and destroying them does involve time. I just think it's a reasonable extrapolation from the observed fact that they don't decay, and the fact that they travel at c to assume that time is meaningless in their frame.

I certainly can't prove it, but I don't think you can prove my hypothesis is invalid either  [;D]
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Offline JPC

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Hi I have no qualification in science, so please correct me. Also this is my first post here on this forum.

I have been taught in school about an equation for calculating time dilation.
T= factor by which the moving object has it's time shortened
t= time experienced by some stationary object
v= velocity of moving object
c= speed of light

T = t/sqrt(1-v^2/c^2)

The important part here is the bit in the square root, which if equal to zero makes the whole thing undefined.

For a photon, v = c

So sqrt(1-c^2/c^2) is the denominator

This simplifies to sqrt(1-1) = sqrt(0) = 0, which means the amount of time experienced is undefined, because t/0 is undefined.

Long story short, the amount of time experienced by a photon during one second of real time is 1/0, undefined (according to my understanding of this equation).

Below is a graph showing how time dilation varies over speed, units on the x axis are c.(source: Wikipedia)



The value on the y axis becomes infinitely large as it approaches 1, but it never reaches 1 (similar to the way y=1/x approaches, but never touches the y or x axis).

I am concerned, as there may be some other equation or consideration I am not aware of that can work around the "undefined" result to the equation above. I am also concerned I have made an error, as I thought someone else would have pulled the numbers out earlier, perhaps they are irrelevant to the question somehow?

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Offline simplified

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Photon has a limited energy,therefore can not touch "1" too. [;)]

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Offline CPT ArkAngel

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Light is not matter, it has no mass. Special Relativity is a special solution and therefore, you cannot conclude anything beyond its limits with it. Alone it is paradoxical...

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Offline JP

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T = t/sqrt(1-v^2/c^2)

That is indeed the equation for time dilation, but it only applies for objects with mass, whereas photons are massless.  You can't just use it for photons, even though it makes it look like you'll divide by zero getting "undefined" time.  The derivation of that equation requires assuming that you're not dealing with massless photons in the first place.

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Offline JP

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Light is not matter, it has no mass. Special Relativity is a special solution and therefore, you cannot conclude anything beyond its limits with it.

Exactly my point.  Special relativity doesn't apply to describe the point of view of photons, and therefore using it to conclude how they "experience" time (or anything else) is flawed.

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Offline simplified

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A photon drags potential mass.Momentum has not Lorentz's factor for speed of photon.And energy has not Lorentz's factor for speed of photon.Without Lorentz's factor:
                         Kinetic Energy = mv²
                Momentum = mv
Momentum and energy of objects have Lorent's factors for speed.
With Lorentz's factor:
Speed of recoil of objects for momentum = L*v
Speed of recoil of objects for energy = L*v/√(L+1)
Then : Kinetic Energy = mv²L²/(L+1)
       Momentum = mvL  

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Offline Bill S

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Quote from: JP
The word "experience" brings with it a lot of connotations that muddies the picture a bit,

Bad choice of word.  [:I] How better to express it?  What about: Is it only in the F of R of an observer that a photon appears to travel through time?

Quote
A photon is emitted by the sun at time t=0 and is absorbed by your eye at time t=8 minutes.  Is this "experiencing time"?

As you rightly point out, this would be experiencing time only if the photon were able to experience anything.

Another requirement would be that what the photon was experiencing was 8 minutes travel.

Would this not be faster than light travel?  [;D]  

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Offline Bill S

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Quote from: Geezer
The process of creating and destroying them does involve time.

Does a photon exist before it is created? - No.
Does a photon exist after it is destroyed? - No.
When is a photon created? - In the present.
When is a photon destroyed? - In the present.
Can we establish that any time is involved between creation and destruction, other than that which is perceived by an observer? - So far I see no evidence of this, so are we just airing our personal beliefs?

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Offline Bill S

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Hi, JPC, welcome. Good to see someone who posts some maths I can understand.  [:)] That's rare.  Keep it up. 

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Offline JP

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Quote from: JP
The word "experience" brings with it a lot of connotations that muddies the picture a bit,

Bad choice of word.  [:I] How better to express it?  What about: Is it only in the F of R of an observer that a photon appears to travel through time?

That's true, but it also describes all cases.  Since there is no F of R of a photon, all frames from which it is observed belong to non-photon observers, and all observers observe the photon moving forward in time.

Quote from: Bill S
Can we establish that any time is involved between creation and destruction, other than that which is perceived by an observer? - So far I see no evidence of this, so are we just airing our personal beliefs?
Exactly my point!  All observers known to science (the observers of SR and GR who can't be moving at the speed of light) see the photon moving through time.  There are no other scientifically viable observers in our current models, so talking about time passing or not passing for them (i.e. from a photon's perspective) is opinion without basis in science.  I think it's proper to say that time from a photon's point of view isn't well-defined, so that the question of time passing for them from their point of view isn't well-posed within our current models.
« Last Edit: 27/01/2011 22:53:55 by JP »

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Offline Geezer

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Quote from: Geezer
The process of creating and destroying them does involve time.

Does a photon exist before it is created? - No.
Does a photon exist after it is destroyed? - No.
When is a photon created? - In the present.
When is a photon destroyed? - In the present.
Can we establish that any time is involved between creation and destruction, other than that which is perceived by an observer? - So far I see no evidence of this, so are we just airing our personal beliefs?

How do you explain the observation that photons do not decay over time when everything else does? Seems like pretty good evidence to me  [:D]
There ain'ta no sanity clause, and there ain'ta no centrifugal force æther.

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Offline yor_on

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Quote from: JP
in physics, there is no theory that defines the frame of reference of a photon

Quote from: JP
We don't know how to describe the reference frame of a photon scientifically, so any claims about it not experiencing time in it's own reference frame aren't scientific.

Looked at from a slightly different perspective; is there any scientific evidence suggesting that a photon's apparent experience of time exists other than in the F of R of an observer?

I'll answer this. The answer is no.

If a photon decayed spontaneously in space, there might be some indication that it experiences a time, but this is not the case. Relative to us however, as JP has noted, photons do experience time.
QC, it's the other way around as I see it. It's to our frame of reference the photons take time, to their 'own', if that one exist, time can't exist. At least not as we experience it, if it did we should observe a 'decay', just as JP describes it.
==

Saying that because they are 'massless' they do not apply to our 'reality'?
Is that science?
« Last Edit: 28/01/2011 02:10:21 by yor_on »
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Offline JP

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Maybe we should start up a thread about what makes particles decay.  I've been thinking about it, and it seems like a pretty deep topic.

Let's say for the sake of argument that we take relativity and tack on an additional set of reference frames for objects moving at the speed of light.  We define time as not existing in these reference frames which means that particles moving at the speed of light don't decay.  The problem is that gluons, which are massless, would be in these reference frames too.  But gluons do decay!  Therefore, these reference frames can't be purely a function of velocity, which would be odd...  Then you'd have one type of reference frame for photons moving at light speed in which time didn't pass and a completely different type for gluons moving at light speed in which time passed.

The other issue is this: aren't electrons also stable?  They can certainly annihilate in collisions, but I don't think that one left alone would spontaneously decay into photons...  I'm not a particle physicist, so I could be wrong on this.

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Offline yor_on

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Nope JP, 'time' is a macroscopic property as I see it. You're lifting up indirect evidence for something not measurable in themselves and theoretically described as 'decaying' as a macroscopic 'truth'. That's not correct.
==

On the other tentacle, that's just what I do when I discuss photons as 'time less' :)
« Last Edit: 28/01/2011 02:56:21 by yor_on »
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Offline yor_on

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So yes JP, in a way you're perfectly correct.
But there is a difference, we don't see gluons.

But we do see photons.
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Offline Geezer

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The other issue is this: aren't electrons also stable?  They can certainly annihilate in collisions, but I don't think that one left alone would spontaneously decay into photons...  I'm not a particle physicist, so I could be wrong on this.

When an atom does emit an electron (beta decay), I don't think it travels quite at c, but I don't know if it decays or not.
There ain'ta no sanity clause, and there ain'ta no centrifugal force æther.