## Photon's Perspective of Time

I'm trying to ask a simple question, which is probably a fatal mistake but...

According to accepted Einsteinian relativity, say I'm travelling at the speed of light. I understand I can't get to that speed. Suppose I was born at that speed, I'm a photon, whatever. From my "photonic perspective" does time pass by? Is it all one big "now", so that from my perspective I'm eternal, or does time merely slow to some finite crawl?

If time does change, even if very slowly, I can understand and have no need of the next question.

If time from the photon's perspective does not change, then how is the perspective of the photon not eternal? In other words, photons are created and destroyed (changed) all the time. Yet if from their perspective time does not change then something does not make sense to me. A particle for which time does not change should have no beginning nor any end.

I'm confused somewhere...

JR

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 Quote by Jesus Rodriguez I'm trying to ask a simple question, which is probably a fatal mistake but... According to accepted Einsteinian relativity, say I'm travelling at the speed of light. I understand I can't get to that speed. Suppose I was born at that speed, I'm a photon, whatever.

Lewis Caroll (who was a mathemetician in real life) has a very amusing and prefectly valid mathematical proof that illustrates the perils of impossible assumptions.

Given 2+2=5, prove that I am the Queen of England.

proof:

2+2=5, but 2+2=4. Therefore 5=4. Therfore 2=1.

Now, me and the Queen are 2. But 2 = 1. Therefore me and the Queen are 1. Therfore I am the Queen of England.

(Or was it the King? It doesn't matter, the proof works either way :-)).

Anyway, the moral of the story is:

Please don't assume that you can move at the speed of light. You can't.

 Blog Entries: 47 Recognitions: Gold Member Homework Help Science Advisor Here's a related discussion http://www.physicsforums.com/showthr...ion%20Question (see the posts near #6)

## Photon's Perspective of Time

 Quote by prevect Please don't assume that you can move at the speed of light. You can't.
The issue here is not one of whether or not he can move at the speed of light. The issue is one of whether or not a photon can "experience".

 Quote by Jesus Rodriguez From my "photonic perspective" does time pass by? Is it all one big "now",
No. Yes.

 Quote by Jesus Rodriguez If time from the photon's perspective does not change, then how is the perspective of the photon not eternal? In other words, photons are created and destroyed (changed) all the time. Yet if from their perspective time does not change then something does not make sense to me. A particle for which time does not change should have no beginning nor any end.
I believe I see your point. A given photon exists only from the point where it is emitted from one atom until it is absorbed by another. That means that, even though a photon does not experience time, it does nonetheless, experience a "lifetime". While every point in its lifetime is experienced simultaneously, it is a discreet, and possibly quite small, set of points.

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 Quote by DaveC426913 The issue here is not one of whether or not he can move at the speed of light. The issue is one of whether or not a photon can "experience". No. Yes.
It is definitely a mistake to import the baggage of frames of reference applicable to a massive observer to a photon - 3 space + 1 time does not work.

This is a frequently asked question, and the frequently given answer is basically that it's not a good question.

 The best way of thinking about it is to say that a photon does not experience time from the instant of its creation in some interaction to the instant of its destruction in another

 Quote by Soul Surfer The best way of thinking about it is to say that a photon does not experience time from the instant of its creation in some interaction to the instant of its destruction in another
Thank you for the responses, (the links were useful). This makes better sense to me now, and as FAQ link says, I don't at all feel stupid for asking the question.

Typically, a good set of answers generate further questions. The link explains how when the equation for relative velocities is used about an object travelling at the speed of light a "meaningless" answer is obtained, signified by an attempt to divide by zero. Some here take that to mean the question itself is somehow meaningless.

However there is an underlying assumption: is mathematics sufficient to contain philosophy? Though no expert I believe that question received a resounding no some time back. That is to say, mathematics does not wholly encompass methods of thinking or valid logical expressions. I believe that while Godel's theorems set a clear limit in any system that involves counting (mathematics), the much older form of logic (sometimes called "term logic") is not so afflicted.

Thus, it may be that some questions while meaningless in mathematical terms, may in fact have a sensible construction nonetheless in other systems, such as natural languages. I find the quote above and that about a photon having no life, but nonethelss a measurable lifespan satisfying answers, and again thank the respondents.

Put in other ways: there are valid questions, and answers, that can not be set in a mathematical framework.

Or, abusing a cliche: "There is more in Heaven and earth than CAN be dreamt of in mathematical philosophy."

JR

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 Quote by Jesus Rodriguez However there is an underlying assumption: is mathematics sufficient to contain philosophy? Though no expert I believe that question received a resounding no some time back. That is to say, mathematics does not wholly encompass methods of thinking or valid logical expressions. I believe that while Godel's theorems set a clear limit in any system that involves counting (mathematics), the much older form of logic (sometimes called "term logic") is not so afflicted.
All you need to do is find something in physics that is devoid of an underlying mathematical description. You'll discover that there's none. So here, it is the assumption that there's something that can't be described mathematically that has no validity.

http://nedwww.ipac.caltech.edu/level...er/Wigner.html

Zz.

 Well heck, if we're going to bring philosophy and reasoning into it then things can get a lot more interesting. Mathematically describe categorizations. It's a matter of opinion whether or not concepts that Math cannot describe are valuable or not. Zapper ascribes to the "not valuable" when it comes to physics. However I can argue that physics is a categorization which is somewhat subjective. Zero is a concept that I'm sure Zapper would find valuable but it is still a concept and does not exist in reality. That's why you can't divide by it. Hand me 100 nothings... So non-physical concepts obviously have some small place in physics as well and the usefullness of a concept is subjective. So I assert that it is not an incontrovertible fact that the question is meaningless. It is instead one of the places that philosophy and reasoning touch physics and the answer is subjective. I also postulate that reasoning that requires concepts that cannot be described mathematically is more valuable than math alone. I'll use the difference between computers and humans as my proof. I believe humans are better overall problem solvers than computers even though computers far exceed humans in speed of calculation and errorless math.

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 Quote by TheAntiRelative I also postulate that reasoning that requires concepts that cannot be described mathematically is more valuable than math alone. I'll use the difference between computers and humans as my proof. I believe humans are better overall problem solvers than computers even though computers far exceed humans in speed of calculation and errorless math.
If you think mathematics is analogous to number crunching, then you have mathematics all wrong.

Again, just show me a physical phenomenon that defies mathematical description. If not, all of this are idle speculation without basis. Now THAT certainly defies mathematical description!

Zz.

 Quote by ZapperZ All you need to do is find something in physics that is devoid of an underlying mathematical description. You'll discover that there's none. So here, it is the assumption that there's something that can't be described mathematically that has no validity. http://nedwww.ipac.caltech.edu/level...er/Wigner.html Zz.

Elegance, a concept that Einstein claimed was an underlying assumption to his theoretical musings. Please translate elegance into a mathematical formula.

JR

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 Quote by Jesus Rodriguez Elegance, a concept that Einstein claimed was an underlying assumption to his theoretical musings. Please translate elegance into a mathematical formula. JR
Elegance is not a physical concept. It's a quality that human gives, like "beauty", something Einstein also described as what a physical equation should be.

Furthermore, ask 10 people the meaning of elegance, and you get 10 different description. Ask 10 people if an object is "elegant", and you get 10 very subjective answer.

Is this what you would consider as a valid quality to describe a physical world, that it simply depends on TASTES? How would you like it that your electronics work simply based on someone's mood and perceived human qualities?

Try again.

Zz.

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 Zero is a concept that I'm sure Zapper would find valuable but it is still a concept and does not exist in reality.
Zero is no less "real" than one. Or, if you prefer, one is no more real than zero.

 That's why you can't divide by it.
No, that's not why you can't divide by it.

 Hand me 100 nothings...