How do we measure faster than light speed ?

[Syne]

http://www.askamathematician.com/2013/04...it-travel/

Exactly: "The movement of a photon (or anything else) is defined entirely from the point of view of anything other than the photon."

IOW, the photon doesn't have a proper frame of reference. Seems you're learning after all. Good for you.

[Secular Sanity]

http://www.askamathematician.com/2013/04...it-travel/

Exactly: "The movement of a photon (or anything else) is defined entirely from the point of view of anything other than the photon."

IOW, the photon doesn't have a proper frame of reference. Seems you're learning after all. Good for you.

Err, we know it doesn’t have a perspective, it’s a photon.

You’re always stumbling. Read it again.

Come on, little guy, you can do it.

[Syne]

http://www.askamathematician.com/2013/04...it-travel/

Exactly: "The movement of a photon (or anything else) is defined entirely from the point of view of anything other than the photon."

IOW, the photon doesn't have a proper frame of reference. Seems you're learning after all. Good for you.

Err, we know it doesn’t have a perspective, it’s a photon.  

You’re always stumbling.   Read it again.  

Come on, little guy, you can do it.

I didn't say "perspective", that's an obvious strawman. I said a photon has no proper frame of reference. Do you agree that a photon has no proper frame of reference? It's never clear, with how you get so dodgy and pretend to be condescending (which is either ignorantly cute or trying to cover for your gaff). And if you agree, why did you say, "Everything is stationary in its own frame of reference."

So yes or no. Does a photon have a proper frame of reference? (Hint:Google is your friend)

[Secular Sanity]

Do you agree that a photon has no proper frame of reference?

Yes.

And if you agree, why did you say, "Everything is stationary in its own frame of reference."

Because it is.  You just assumed that I was referring to a photon’s frame of reference.

As far as the photon’s perspective is concerned, from the photon's point of view it is not moving at all.  From our point of view it is moving, but we’re not.

Time genuinely doesn’t pass from the “perspective” of a photon but, like everything in relativity, the situation isn’t as simple as photons “being in stasis” until they get where they’re going.  Whenever there’s a “time effect” there’s a “distance effect” as well, and in this case we find that infinite time dilation (no time for photons) goes hand in hand with infinite length contraction (there’s no distance to the destination).

The name “relativity” (as in “theory of…”) comes from the central tenet of relativity, that time, distance, velocity, even the order of events (sometimes) are relative.  This takes a few moments of consideration; but when you say that something’s moving, what you really mean is that it’s moving with respect to you.

Everything has its own “coordinate frame”.  Your coordinate frame is how you define where things are.  If you’re on a train, plane, rickshaw, or whatever, and you have something on the seat next to you, you’d say that (in your coordinate frame) that object is stationary.  In your own coordinate frame you’re never moving at all.

Everything is stationary from its own perspective.  Movement is something other things do.  When you describe the movement of those other things it’s always in terms of your notion of space and time coordinates.

If a photon doesn't experience time then how can it travel?

It's never clear, with how you get so dodgy and pretend to be condescending (which is either ignorantly cute or trying to cover for your gaff).

From my "perspective," it is you who is condescending and demeaning, and not only to me, but to almost everyone.

Nice!

[Syne]

Do you agree that a photon has no proper frame of reference?

Yes.

And if you agree, why did you say, "Everything is stationary in its own frame of reference."

Because it is.  You just assumed that I was referring to a photon’s frame of reference.

So "Everything is stationary in its own frame of reference" was just a non-sequitur in a post wholly about photons?

As far as the photon’s perspective is concerned, from the photon's point of view it is not moving at all. From our point of view it is moving, but we’re not.

There is no photon "perspective" or "point of view". Remember this from your link:

The movement of a photon (or anything else) is defined entirely from the point of view of anything other than the photon. - http://www.askamathematician.com/2013/04...it-travel/

Go back a reread your own link. Take special care to note that "perspective" is in scare quotes when describing a photon and that "point of view" is only applicable to "anything other than the photon". Or just trivially imagine what zero time and zero distance is....i.e. nothing. "Photon perspective" is a scientifically meaningless bit of layman-oriented frippery, nothing more. Extrapolating our experience of a rest frame to a phenomenon that has no rest frame only confuses the finer points of physics.

"Not moving" is meaningless where there is no distance.

[Secular Sanity]

So "Everything is stationary in its own frame of reference" was just a non-sequitur in a post wholly about photons?

It wasn’t a non-sequitur because I wasn’t arguing with you.  

Go back a reread your own link.

No.  You can go back and reread your own quote from that link.

Exactly: "The movement of a photon (or anything else) is defined entirely from the point of view of anything other than the photon."

IOW, the photon doesn't have a proper frame of reference. Seems you're learning after all. Good for you.

IOW, I wasn't referring to a photon’s frame of reference.

"Everything has its own “coordinate frame”.  Your coordinate frame is how you define where things are.  If you’re on a train, plane, rickshaw, or whatever, and you have something on the seat next to you, you’d say that (in your coordinate frame) that object is stationary.  In your own coordinate frame you’re never moving at all.

The last coordinate to consider is time, which is just whatever your clock reads.  One of the very big things that came out of Einstein’s original paper on special relativity is that not only will different perspectives disagree on where things are, and how fast they’re moving, different perspectives will also disagree on what time things happen and even how fast time is passing.

When an object moves past you, you define its velocity by looking at how much of your distance it covers, according to your clock, and this (finally) is the answer to the question.  The movement of a photon (or anything else) is defined entirely from the point of view of anything other than the photon."

Or just trivially imagine what zero time and zero distance is....i.e. nothing. "Photon perspective" is a scientifically meaningless bit of layman-oriented frippery, nothing more. Extrapolating our experience of a rest frame to a phenomenon that has no rest frame only confuses the finer points of physics.


"Not moving" is meaningless where there is no distance.

What…are you the gedanken police now, or is this similar to our philosophical discussions (the world according to Syne)?

Not only is it useful when considering FTL, time dilation, and length contraction, it adds a little pizazz to my saying.

Nothing happens at once.  At once is not everywhere.  Only light is everywhere and everywhere at once.

And again…

[RainbowUnicorn]

Syne

what is light when it is not moving ?

Light can only exist moving.


why cant we gather existing light and store it without converting it ?

Massless particles, like photons, can only be said to exist when their momentum lends them relativistic mass. If you could stop them, they would lose all the properties that allow us to observe them. And since the first law of thermodynamics (conservation of energy) says we cannot remove momentum without that energy being converted to something else, even though the photon disappears, its energy must be absorbed elsewhere.

Thanks Syne. this is what perplexes me with thermodynamics & its action with photons & how we observe them.
i was pondering if, and if so, then what realtion this has to schrodengers theory in causality.
(my limited understanding is that schrodengers theory is accepted scientific fact in some frame of reference)
i suspect i may be over simplifying it to a point where it becomes non functional in that

my thought = "do we as the observer play some part in the relationship of the speed of light given that we interact with it simply by observing it" ?

[Syne]

So "Everything is stationary in its own frame of reference" was just a non-sequitur in a post wholly about photons?

It wasn’t a non-sequitur because I wasn’t arguing with you.  

What was the point of this then?

Everything is stationary in its own frame of reference, but of course Syne already knows this because he is so smart and yet so gracious.

To what did it relate, if not photons in a post about photons in a thread about light? Go ahead...explain exactly what you meant.

Exactly: "The movement of a photon (or anything else) is defined entirely from the point of view of anything other than the photon."

IOW, the photon doesn't have a proper frame of reference. Seems you're learning after all. Good for you.

IOW, I wasn't referring to a photon’s frame of reference.

"Everything has its own “coordinate frame”.  Your coordinate frame is how you define where things are.  If you’re on a train, plane, rickshaw, or whatever, and you have something on the seat next to you, you’d say that (in your coordinate frame) that object is stationary.  In your own coordinate frame you’re never moving at all.

The last coordinate to consider is time, which is just whatever your clock reads.  One of the very big things that came out of Einstein’s original paper on special relativity is that not only will different perspectives disagree on where things are, and how fast they’re moving, different perspectives will also disagree on what time things happen and even how fast time is passing.

When an object moves past you, you define its velocity by looking at how much of your distance it covers, according to your clock, and this (finally) is the answer to the question.  The movement of a photon (or anything else) is defined entirely from the point of view of anything other than the photon."

Then what were you referring to?

Or just trivially imagine what zero time and zero distance is....i.e. nothing. "Photon perspective" is a scientifically meaningless bit of layman-oriented frippery, nothing more. Extrapolating our experience of a rest frame to a phenomenon that has no rest frame only confuses the finer points of physics.


"Not moving" is meaningless where there is no distance.

What…are you the gedanken police now, or is this similar to our philosophical discussions (the world according to Syne)?

Not only is it useful when considering FTL, time dilation, and length contraction, it adds a little pizazz to my saying.

When it's obvious the OP lacks even a basic understanding, playing fast and loose with terminology can only hinder comprehension. But you're not concerned about that, are you? You're much more concerned with defending your ego.

And no, it's not useful when considering FTL, time dilation, and length contraction because at c there is no time or distance (so a sub-light speed is more revealing) and no actual science justifies any factual discussion of FTL.

---

Massless particles, like photons, can only be said to exist when their momentum lends them relativistic mass. If you could stop them, they would lose all the properties that allow us to observe them. And since the first law of thermodynamics (conservation of energy) says we cannot remove momentum without that energy being converted to something else, even though the photon disappears, its energy must be absorbed elsewhere.

Thanks Syne. this is what perplexes me with thermodynamics & its action with photons & how we observe them.
i was pondering if, and if so, then what realtion this has to schrodengers theory in causality.
(my limited understanding is that schrodengers theory is accepted scientific fact in some frame of reference)
i suspect i may be over simplifying it to a point where it becomes non functional in that

my thought = "do we as the observer play some part in the relationship of the speed of light given that we interact with it simply by observing it" ?

Observation only effects light when we attempt to measure the particles of light called photons. Simply seeing light has no effect on it, because the phenomena we see doesn't rely on a strictly particle form of light. ITOH, when we attempt to measure photons, our measurement forces the wave nature of light (like the wavelengths that produce different colors) to become particles which have a definite position in space.

[Secular Sanity]

What was the point of this then?

Well, maybe I just wanted to see if you’d pop off again.

To what did it relate, if not photons in a post about photons in a thread about light? Go ahead...explain exactly what you meant.

It was in relation to us.  I needed to say something about inertial frames to show that there is no absolute frame of reference and that objects are always measured relative to the position of another object.  

Then what were you referring to?

Already answered.

Or just trivially imagine what zero time and zero distance is....i.e. nothing. "Photon perspective" is a scientifically meaningless bit of layman-oriented frippery, nothing more. Extrapolating our experience of a rest frame to a phenomenon that has no rest frame only confuses the finer points of physics.

"Not moving" is meaningless where there is no distance.

---

And no, it's not useful when considering FTL, time dilation, and length contraction because at c there is no time or distance (so a sub-light speed is more revealing) and no actual science justifies any factual discussion of FTL.

Sure it is. The finite speed being the same for all observers is counterintuitive. The photon’s perspective shows how space and time are intricately linked together and how c is a fundamental feature of space-time.

It’s a little sad, though, when you think of it.  Especially for those who believe in something that extends beyond time and space. Even though photons travel billions of light years across space, their experience of distance would contract to a single point, and the time for the trip would be instantaneous.  

Emitted and absorbed…poof!  Timelessness…careful what you wish for.

[Syne]

To what did it relate, if not photons in a post about photons in a thread about light? Go ahead...explain exactly what you meant.

It was in relation to us.  I needed to say something about inertial frames to show that there is no absolute frame of reference and that objects are always measured relative to the position of another object.  

Now explain how that is not a non-sequitur here:

Question: What is light when it is not moving?  

Answer:  It becomes stored energy, which is no longer light.

By using two light beams, they can induce an electromagnetic transparent medium, where both beams can propagate with almost no absorption.

If they turn down the laser that made the medium transparent, they can reduce the polaritons made of photons, and then they can increase the polaritions made of atoms.  The light is then effectively stored in the medium.  The photons become dark-state polaritons, which are excitations in the medium.  In other words, the medium becomes briefly opaque.  When they turn the laser back up, the polaritions are converted back into photons.

Everything is stationary in its own frame of reference, but of course Syne already knows this because he is so smart and yet so gracious.

None of what you said here requires anything about "inertial frames" or "relative measurement". So are we about to the point in the discussion where you usually beg off by saying you were "just joking"?

Or just trivially imagine what zero time and zero distance is....i.e. nothing. "Photon perspective" is a scientifically meaningless bit of layman-oriented frippery, nothing more. Extrapolating our experience of a rest frame to a phenomenon that has no rest frame only confuses the finer points of physics.

"Not moving" is meaningless where there is no distance.

---

And no, it's not useful when considering FTL, time dilation, and length contraction because at c there is no time or distance (so a sub-light speed is more revealing) and no actual science justifies any factual discussion of FTL.

Sure it is. The finite speed being the same for all observers is counterintuitive. The photon’s perspective shows how space and time are intricately linked together and how c is a fundamental feature of space-time.

It’s a little sad, though, when you think of it.  Especially for those who believe in something that extends beyond time and space. Even though photons travel billions of light years across space, their experience of distance would contract to a single point, and the time for the trip would be instantaneous.  

Emitted and absorbed…poof!  Timelessness…careful what you wish for.

This thread hasn't even progressed anywhere near approaching how c is invariant in all inertial frames (and if you think the OP is there, you're deluded). Still sounds like you're just trying to pad your ego at the expense of helping anyone actually learn something (much like you're doing here). And even if it had gotten that far, the time dilation and length contraction at c do not tell us anything, since both are zero. Only at sub-light speeds do we see the counterintuitive consequences (like the relativity of simultaneity) of c being invariant and how notions of time and distance change at significant fractions of c.

Again, your supposed "experience" of a photon is meaningless, because it is zero. It's not sad...a photon is not a widdle wost puppy...no matter how much your overactive emotions cry out to make a fanciful and personified story of everything. At least animals actually do have experience.