Do photons age? Do they remain stationary in x4?

[yossell]

`Biological age' should be distinguished from `chronological age'. The former tracks the wear and tear of an organism over time, the latter the amount of time that has passed for an organism. While 'biological age' clearly refers to organisms, its use could be extended to other systems, to track their changes too.

Biological age clearly must involve change. A forty year old man in a sixteen year old's body implies that certain changes have gone slowly for him and also is illegal in some countries. Chronological age does not so obviously require change (though if time necessarily requires some kind of change, it may) and it's theoretically possible for periodic system to `experience' time, in that it goes through a sequence of changes, yet returning to exactly the same qualitative state.

(Perhaps, then, here I disagree with Fredrik's last post )

It seems to me that the argument that the decay rate of fundamental particles shows that their `biological' age does not change - they are intrinsically the same for the whole of their lifetime. But the notion of time passed, and in particular, relativistic time dilation, also makes sense for muons - they do have a half life, which is a function of the proper time, and fast traveling muons live longer.

By contrast, traveling on light-cones, not even this much can be said for photons.

 

[brunoeinstein]

As Brian Greene points out in the Appendix to Chapter 2 of The Elegant
Universe, we note that from the space-time position 4-vector
x=(ct,x1,x2,x3), we can create the velocity 4-vector u=dx/d(tau),
where tau is the proper time defined by
d(tau)^2=dt^2-c^-2(dx1^2+dx2^2+dx3^2). Then the "speed through
space-time" is the magnitude of the 4-vector u,
((c^2dt^2-dx^2)/(dt^2-c^-2dx^2))^(1/2), which is identically the speed
of light c. Now, we can rearrange the equation
c^2(dt/d(tau))^2-(dx/d(tau))^2=c^2 to be c^2(d(tau)/dt))^2
+(dx/d(tau))^2=c^2. This shows that an increase of an object's speed
through space, (dx/d(tau))^2)^(1/2)= dx/d(tau) must be accompanied by
a decrease in d(tau)/dt which is the object's speed through time,
which also may be considered the rate at which time elapses on it's
own clock d(tau) or the proper time, as compared with that on our
stationary clock dt.

So it seems that as an object propagates at c through the three spatial dimensions, it must propagate at 0 through the fourth dimension.

Hence it would seem that photons remain stationary in the fourth dimension. For if they moved at all in the fourth dimension, their velocity would be greater than c, which is impossible.

 

[Dale]

So it seems that as an object propagates at c through the three spatial dimensions, it must propagate at 0 through the fourth dimension.

Hence it would seem that photons remain stationary in the fourth dimension.

This is certainly not correct. The fact that the proper time along a lightlike worldline is 0 does not imply that the worldline does not go through coordinate time.

Btw, although the four velocity of any timelike particle has a magnitude of c, the four velocity of a lightlike particle is undefined.

 

[Dale]

`Biological age' should be distinguished from `chronological age'.

I guess I would use "age" to refer to the former and "proper time" to refer to the latter.

 

[brunoeinstein]

This is certainly not correct. The fact that the proper time along a lightlike worldline is 0 does not imply that the worldline does not go through coordinate time.

yes dale,

indeed our watches would continue ticking as photons zoom on by.

i assume that you are picturing a space-time diagram and a light cone. the time on that space-time diagram is in our frame.

what brian greene is saying is that the photon is moving along with the fourth dimension, as it is staying stationary in x4. as the velocity of all objects through space-time is c, and as all of a photon's velocity is directed through space (x1, x2, x3), it must thus be stationary in the fourth dimension (x4).

that is what the math is saying.

best. :)

 

[Dale]

what brian greene is saying is that the photon is moving along with the fourth dimension, as it is staying stationary in x4. as the velocity of all objects through space-time is c, and as all of a photon's velocity is directed through space (x1, x2, x3), it must thus be stationary in the fourth dimension (x4).

that is what the math is saying.

No, from your comments about the fourth dimension you are clearly referring to coordinate time and a photon clearly is not stationary in coordinate time.

Also, your references to the four-velocity apply only for timelike particles, not lightlike particles. The four-velocity is not defined for a photon's worldline (division by 0). That is why you have to use an affine parameter instead of proper time for a photon.

 

[brunoeinstein]

No, from your comments about the fourth dimension you are clearly referring to coordinate time and a photon clearly is not stationary in coordinate time.

Also, your references to the four-velocity apply only for timelike particles, not lightlike particles. The four-velocity is not defined for a photon's worldline (division by 0). That is why you have to use an affine parameter instead of proper time for a photon.

Indeed a photon is not stationary in time as we measure it on our watches.

But too, a photon does not age.

Or are you saying that Brian Greene is wrong? "Brian Greene writes in the Elegant Universe:

pg 49

...in the majority of circumstances (slow speeds) most of an objects motion is thru time, not space...the maximum speed through space occurs if all of an objects motion through time is diverted to motion through space...thus light does not get old; a photon that emerged from the big bangis the same age today as it was then.

"

Greene states "thus light does not get old; a photon that emerged from the big bang is the same age today as it was then."

This is true.

 

[Kitesurfer]

Do photons age?
Time has no meaning in photon rest frame, nor for any zero mass particle moving at c. Time is "experienced" only by mass particles. Therefore, only interaction of photon and a mass particle yields information about time.

 

[brunoeinstein]

Do photons age?
Time has no meaning in photon rest frame, nor for any zero mass particle moving at c. Time is "experienced" only by mass particles. Therefore, only interaction of photon and a mass particle yields information about time.

so you agree with brian greene i take it?

Greene states "thus light does not get old; a photon that emerged from the big bang is the same age today as it was then."

This is true.

 

[Kitesurfer]

so you agree with brian greene i take it?

Greene states "thus light does not get old; a photon that emerged from the big bang is the same age today as it was then."

This is true.

Yes.
A photon that was emitted 13 plus billions years ago, right after the initial condensation of electrons / protons that made the universe transparent to photons and enabled its propagation without scattering on mass particles (circa 300 thousands years after the big bang), is received by our detector via its interaction with a mass particle in the detector. Only then a time is recorded, i.e. it has a meaning.

 

[brunoeinstein]

Yes.
A photon that was emitted 13 plus billions years ago, right after the initial condensation of electrons / protons that made the universe transparent to photons and enabled its propagation without scattering on mass particles (circa 300 thousands years after the big bang), is received by our detector via its interaction with a mass particle in the detector. Only then a time is recorded, i.e. it has a meaning.

More from Brian Greene & Einstein,

"Einstein proclaimed that all objects in the universe are always traveling at one fixed speed--that of light. . . We now see that time slows down when an object moves relative to us because this diverts some of its motion through time into motion through space. The speed of an object through space is thus merely a reflection of how much of its motion through time is diverted." -- p. 50, THE ELEGANT UNIVERSE (read it for yourself if you log in @ https://www.amazon.com/dp/0375708111/?tag=pfamazon01-20)

1. "Einstein proclaimed that all objects in the universe are always traveling at one fixed speed--that of light." --Brian Greene

2. Fact: A photon travels at c through the three spatial dimensions.

3. "The speed of an object through space is thus merely a reflection of how much of its motion through time is diverted." --Brian Greene

4. Because a photon moves at c through the three spatial dimensions, a photon's "motion through time must be entirely diverted."

5. Ergo, a photon has no velocity component in the fourth dimension.

6. Ergo a photon stays at the same place in the fourth dimension, as it has no motion in the fourth dimension, all its "motion through time being diverted," as Brian Greene and Einstein state.
B.E.

 

[Fredrik]

I found more discussion on Brian Greene's writings here:

This was only your third post in this forum, and you're already quoting a crackpot who keeps creating new accounts here just to be able to post his "moving dimensions" nonsense. (No, not Greene). It's not hard to guess who you are. And linking to crackpot stuff is against the forum rules, no matter who you are.

More from Brian Greene & Einstein,

I think Greene's explanation of SR is really bad, so I wouldn't recommend anyone to try to learn SR from his writings.

 

[brunoeinstein]

This was only your third post in this forum, and you're already quoting a crackpot who keeps creating new accounts here just to be able to post his "moving dimensions" nonsense. (No, not Greene).

sorry about that!

i was searching for greene's passage on photons not aging nor traveling through x4, and came across the passage.

perhaps we should stick to greene's text which i found at amazon.com: https://www.amazon.com/dp/0375708111/?tag=pfamazon01-20

if you log in, it will let you read it directly as they have made that page available. or, perhaps you have the book.

More from Brian Greene & Einstein,

"Einstein proclaimed that all objects in the universe are always traveling at one fixed speed--that of light. . . We now see that time slows down when an object moves relative to us because this diverts some of its motion through time into motion through space. The speed of an object through space is thus merely a reflection of how much of its motion through time is diverted." -- p. 50, THE ELEGANT UNIVERSE (read it for yourself if you log in @ https://www.amazon.com/dp/0375708111/?tag=pfamazon01-20)

1. "Einstein proclaimed that all objects in the universe are always traveling at one fixed speed--that of light." --Brian Greene

2. Fact: A photon travels at c through the three spatial dimensions.

3. "The speed of an object through space is thus merely a reflection of how much of its motion through time is diverted." --Brian Greene

4. Because a photon moves at c through the three spatial dimensions, a photon's "motion through time must be entirely diverted."

5. Ergo, a photon has no velocity component in the fourth dimension.

6. Ergo a photon stays at the same place in the fourth dimension, as it has no motion in the fourth dimension, all its "motion through time being diverted," as Brian Greene and Einstein state.



B.E.

 

[brunoeinstein]

I think Greene's explanation of SR is really bad, so I wouldn't recommend anyone to try to learn SR from his writings.

What, specifically, do you find "really bad" about Greene's explanations of SR?

Are you saying that he is wrong? If so, how so, specifically?

It is not enough in life nor education to criticize others in an ad hominem manner, but one must always a) qualify one's statements, and b) suggest the better path for everyone's elucidation.

Who do you suggest we learn SR from?

Thanks in advance!

:) BR

 

[yossell]

but one must always a) qualify one's statements,

Practice what you preach much?

 

[brunoeinstein]

Practice what you preach much?

I hope so! Where do you think I am falling short?

I will make amends to correct any shortcomings.

Thanks! :)

 

[brunoeinstein]

I think Greene's explanation of SR is really bad, so I wouldn't recommend anyone to try to learn SR from his writings.

Hello Fredrick,

I did some research on Brian Greene. He is one of the most famous physicists of our era, and too, he is one of the most famous teachers of physics.

http://en.wikipedia.org/wiki/Brian_Greene
http://www.columbia.edu/cu/physics/fac-bios/Greene/faculty.html

Please elaborate on why you say that, "Greene's explanation of SR is really bad, so I wouldn't recommend anyone to try to learn SR from his writings."

Greene is a world-renown scientist with degrees from Oxford in theoretical physics.

Why do you think that he is not good?

The New York Times Book Review wrote:

The New York Times Book Review - George Johnson

Greene...explor[es] the ideas and recent developments with a depth and clarity I wouldn't have thought possible. He has a rare ability to explain even the most evanescent ideas in a way that gives at least the illusion of understnding.He developes one fresh new insight after another...In the great tradition of physicists writing for the masses, The Elegant Universe sets a standard that will be hard to beat.

--http://search.barnesandnoble.com/The-Elegant-Universe/Brian-Greene/e/9780375708114#TABS

Scientific American - Chris Quigg

Beautifully told...The Elegant Universe presents the ideas and aspirations — and some of the characters — of string theory with clarity and charm...a thoughtful and important book.

The London Review of Books - Ellis

...I can only say that Greene's book is an explanatory tour-de-force...It would be hard to imagine anyone producing a clearer account than this of the difficult ideas involved, and Greene even brings out something of the actual excitement of scientific discovery...

Are you saying, Fredrick, that Greene as these sources are not to be trusted? What are your credentials, if we may ask? Perhaps that will help us to put your opinion in proper perspective? Thanks!

Given the unanimous praise for Brian Greene & his book, as well as for Einstein, coming from everywhere, I am going to have to keep with this explanation & interpretation:

More from Brian Greene & Einstein,

"Einstein proclaimed that all objects in the universe are always traveling at one fixed speed--that of light. . . We now see that time slows down when an object moves relative to us because this diverts some of its motion through time into motion through space. The speed of an object through space is thus merely a reflection of how much of its motion through time is diverted." -- p. 50, THE ELEGANT UNIVERSE (read it for yourself if you log in @ https://www.amazon.com/Elegant-Univer...der_0375708111&tag=pfamazon01-20)

1. "Einstein proclaimed that all objects in the universe are always traveling at one fixed speed--that of light." --Brian Greene

2. Fact: A photon travels at c through the three spatial dimensions.

3. "The speed of an object through space is thus merely a reflection of how much of its motion through time is diverted." --Brian Greene

4. Because a photon moves at c through the three spatial dimensions, a photon's "motion through time must be entirely diverted."

5. Ergo, a photon has no velocity component in the fourth dimension.

6. Ergo a photon stays at the same place in the fourth dimension, as it has no motion in the fourth dimension, all its "motion through time being diverted," as Brian Greene and Einstein state.



B.E.

 

[Naty1]

Bruno...

The time measured on a clock or watch relies on the emission and propagation of photons, be it in the context of an unwinding clock spring or an oscillating quartz crystal, or even the beating of a heart. And photons are matter that surf the fourth expanding dimension.

really humorous...nice try! but insofar as current science has determined, purely speculative...

Einstein proclaimed that all objects in the universe are always traveling at one fixed speed--that of light

..

that's not quite the quote... ...you mean "...traveling through spacetime.." at one fixed speed...so it's the spacetime interval that IS invarient...

I do agree with the rest of your post immediately above including " Please elaborate on why you say that, "Greene's explanation of SR is really bad, so I wouldn't recommend anyone to try to learn SR from his writings."...for a largely non mathematical discussion of relativity Greene does a good job..and is consistent from what I have seen with several other prominent physicsts.

 

[brunoeinstein]

Bruno...



really humorous...nice try! but insofar as current science has determined, purely speculative...

..

that's not quite the quote... ...you mean "...traveling through spacetime.." at one fixed speed...so it's the spacetime interval that IS invarient...

I do agree with the rest of your post immediately above including " Please elaborate on why you say that, "Greene's explanation of SR is really bad, so I wouldn't recommend anyone to try to learn SR from his writings."...for a largely non mathematical discussion of relativity Greene does a good job..and is consistent from what I have seen with several other prominent physicsts.

Yes, I agree. Above I quoted: "1. "Einstein proclaimed that all objects in the universe are always traveling at one fixed speed--that of light." --Brian Greene



BE :)

 

[brunoeinstein]

thanks all! well, seems like we're making some progress on a consensus!

at this point, is there anyone who does not agree with this, or finds fault with the following:

More from Brian Greene & Einstein,

"Einstein proclaimed that all objects in the universe are always traveling at one fixed speed--that of light. . . We now see that time slows down when an object moves relative to us because this diverts some of its motion through time into motion through space. The speed of an object through space is thus merely a reflection of how much of its motion through time is diverted." -- p. 50, THE ELEGANT UNIVERSE (read it for yourself if you log in @ https://www.amazon.com/Elegant-Univer...der_0375708111&tag=pfamazon01-20)

1. "Einstein proclaimed that all objects in the universe are always traveling at one fixed speed--that of light." --Brian Greene

2. Fact: A photon travels at c through the three spatial dimensions.

3. "The speed of an object through space is thus merely a reflection of how much of its motion through time is diverted." --Brian Greene

4. Because a photon moves at c through the three spatial dimensions, a photon's "motion through time must be entirely diverted."

5. Ergo, a photon has no velocity component in the fourth dimension.

6. Ergo a photon stays at the same place in the fourth dimension, as it has no motion in the fourth dimension, all its "motion through time being diverted," as Brian Greene and Einstein state.



B.E.

if there is anyone who does not agree with the above, please share your opinion and characterize why you do not agree with the above. thanks all!

 

[Dale]

But too, a photon does not age.

I agree, but that has nothing whatsoever to do with its passage through coordinate time (your x4).

Regarding Brian Greene, he is a good physicist, but you are quoting a pop-sci book of his. Like all pop-sci books it is necessarily very sloppy. It is not a useful reference, nor is it intended to be.

 

[Dale]

1. "Einstein proclaimed that all objects in the universe are always traveling at one fixed speed--that of light." --Brian Greene

This is sloppy useage. He is referring to the norm of the four-velocity, which is only defined for massive particles. Not photons. You cannot extend conclusions or reasoning based on this to photons or other massless particles.

4. Because a photon moves at c through the three spatial dimensions, a photon's "motion through time must be entirely diverted."

Meaning that its proper time is 0.

5. Ergo, a photon has no velocity component in the fourth dimension.

Incorrect. You are confusing coordinate time (the fourth dimension) with proper time (the spacetime interval along a worldline).

 

[brunoeinstein]

"1. "Einstein proclaimed that all objects in the universe are always traveling at one fixed speed--that of light." --Brian Greene"
^^^^
This is sloppy useage. He is referring to the norm of the four-velocity, which is only defined for massive particles. Not photons. You cannot extend conclusions or reasoning based on this to photons or other massless particles.

So are you saying that Einstein's statement, "Einstein proclaimed that all objects in the universe are always traveling at one fixed speed--that of light." does not apply to photons?

Are you saying that light (photons) doth not travel at the speed of light?

You do realize, that that is entirely ridiculous. Right?

It doth appear that you are the one who is being sloppy, sir.
BE :)

 

[Dale]

Are you saying that light (photons) doth not travel at the speed of light?

Read what I said:

This is sloppy useage. He is referring to the norm of the four-velocity, which is only defined for massive particles. Not photons. You cannot extend conclusions or reasoning based on this to photons or other massless particles.

Green's quote (misattributed to Einstein) can either refer to the norm of the four-velocity or the norm of the three-velocity. If it refers to the norm of the three-velocity then it is simply not true, and if it refers to the norm of the four-velocity then it does not apply to photons since the four-velocity is undefined for them.

You seem to be confusing three-velocity and four-velocity as well as confusing proper time and coordinate time. Your confusion is not surprising if your sole source of information on relativity is a pop-sci book.

 

[brunoeinstein]

Read what I said:

Green's quote (misattributed to Einstein) can either refer to the norm of the four-velocity or the norm of the three-velocity. If it refers to the norm of the three-velocity then it is simply not true, and if it refers to the norm of the four-velocity then it does not apply to photons since the four-velocity is undefined for them.

I read EXACTLY what you said and I responded to it.

Everyone can see that I am responding to EXACTLY what you said, as I quote EXACTLY what you said.

"1. "Einstein proclaimed that all objects in the universe are always traveling at one fixed speed--that of light." --Brian Greene"
^^^^
This is sloppy useage. He is referring to the norm of the four-velocity, which is only defined for massive particles. Not photons. You cannot extend conclusions or reasoning based on this to photons or other massless particles.

So are you saying that Einstein's statement, "Einstein proclaimed that all objects in the universe are always traveling at one fixed speed--that of light." does not apply to photons?

Are you saying that light (photons) doth not travel at the speed of light?

You do realize, that that is entirely ridiculous. Right?

It doth appear that you are the one who is being sloppy, sir.
BE :)

 

[jtbell]

So are you saying that Einstein's statement, "Einstein proclaimed that all objects in the universe are always traveling at one fixed speed--that of light." does not apply to photons?

That's Greene's statement, not Einstein's.

 

[brunoeinstein]

That's Greene's statement, not Einstein's.

Yes it is Greene stating what Einstein's statement was in these exact words from Greene's book The Elegant Universe, "Einstein proclaimed that all objects in the universe are always traveling at one fixed speed--that of light."

 

[DaTario]

[putting Fredrik's response in different words]

For a given type of particle, the probability that it will decay during the next second does not depend on the time that the particle has already "lived." It is constant. As far as we know, there is no difference between a muon that was created one microsecond ago, versus one that was created one second ago, or one that was created one hour ago. (assuming of course that it still exists)

It seems wrong to think this way, as a given dsitribution of relative frequencies in a series of events (decays) can be described in general by more than one probabilistc model. If you have an exponential decay it means that the number of decays decrease with the number of active entities. But it does not mean that the only possible model describing this statistical result is a markovian process (without memory).

Best wishes

DaTario

 

[Fredrik]

What, specifically, do you find "really bad" about Greene's explanations of SR?

The claim that everything moves through spacetime at speed c is just saying that the Minkowski square of the four-velocity is equal to -c² (or +c² if you use the +--- version of the metric instead of -+++). As DaleSpam already mentioned, this isn't even true for photons; the Minkowski square of a photon's four-velocity is 0, not -c². For massive particles, the claim is true, but it's just a normalization convention. It's like saying "If Mike goes completely bald, he won't have any hair on his head". It tells us something about how we have chosen to define certain words, but it doesn't tell us anything about the physics.

So what Greene does is to take a statement that's vacuously true for massive particles and wrong for massless particles, and insinuate that it's a deep and profound statement about all particles.

Who do you suggest we learn SR from?

I like the SR section of Schutz's GR book. Taylor & Wheeler is the book that gets the most recommendations from competent people here in the forum, so I assume that's a good choice too, but I haven't read it myself.

 

[Fredrik]

Let's look at some Greene quotes that were posted in another thread some time ago.

...Einstein found that precisely this idea - the sharing of motion between different dimensions - underlies all of the remarkable physics of special relativity...

...Einstein proclaimed that all objects in the universe are always traveling through space-time at one fixed speed - that of light...

I don't believe Einstein said any of these things. These are Greene's own thoughts about SR, not Einstein's.

The claim that all objects are traveling through spacetime at speed c, is true for massive particles, if "speed through spacetime" is defined as $$\sqrt{-u^T\eta u}$$ where u is the four-velocity, but then it isn't true for massless particles. So he's already in trouble here.

...If an object does not move through space all of the objects motion is used to travel through time...

No objection here. Note that he seems to be talking about motion such that every point on the world line has the same spatial coordinates in some inertial frame.

...Something traveling at light speed through space will have no speed left for motion through time. Thus light does not get old; a photon that emerged from the big bang is the same age today as it was then. There is no passage of time at the speed of light.

The first claim is only valid if what he said in the first quote is correct, and it isn't. The claim also doesn't make sense, because when he talked about no motion through space, he must have meant that all points on the world line have the same spatial coordinates in some inertial frame, so no motion through time should mean that all points on the world line has the same time coordinate in some inertial frame. But such a world line represents infinite speed, not light speed.

The last claim is nonsense for the reasons I explained earlier in this thread.

 

[Dale]

I read EXACTLY what you said and I responded to it.

Everyone can see that I am responding to EXACTLY what you said, as I quote EXACTLY what you said.

Instead of going in circles why don't you respond to the substantive criticisms above. Specifically regarding your confusion between the three-velocity and the four-velocity and your confusion between proper time and coordinate time. Do you even know what those terms mean? Probably not if your only source of information is a pop-sci book. We can help explain these terms, but we need to know what level of detail to present.

Do you understand that proper time is not a dimension? Do you realize that the four-velocity of a photon is not well-defined? Do you understand how the chain of logic you laid out above is flawed and does not lead to the conclusion you assert?

 

[brunoeinstein]

The claim that everything moves through spacetime at speed c is just saying that the Minkowski square of the four-velocity is equal to -c² (or +c² if you use the +--- version of the metric instead of -+++). As DaleSpam already mentioned, this isn't even true for photons; the Minkowski square of a photon's four-velocity is 0, not -c². For massive particles, the claim is true, but it's just a normalization convention. It's like saying "If Mike goes completely bald, he won't have any hair on his head". It tells us something about how we have chosen to define certain words, but it doesn't tell us anything about the physics.

So what Greene does is to take a statement that's vacuously true for massive particles and wrong for massless particles, and insinuate that it's a deep and profound statement about all particles.


I like the SR section of Schutz's GR book. Taylor & Wheeler is the book that gets the most recommendations from competent people here in the forum, so I assume that's a good choice too, but I haven't read it myself.

Well, Greene is right.

Photons travel at c--the velocity of light. I'm still not sure why you have a problem with Greene and why you call him sloppy. Everything he says is 100% true, whereas you earler stated:

Originally Posted by DaleSpam View Post

"1. "Einstein proclaimed that all objects in the universe are always traveling at one fixed speed--that of light." --Brian Greene"
^^^^
This is sloppy useage. He is referring to the norm of the four-velocity, which is only defined for massive particles. Not photons. You cannot extend conclusions or reasoning based on this to photons or other massless particles.

So are you saying that Einstein's statement, "Einstein proclaimed that all objects in the universe are always traveling at one fixed speed--that of light." does not apply to photons?

Are you saying that light (photons) doth not travel at the speed of light?

You do realize, that that is entirely ridiculous. Right?

It doth appear that you are the one who is being sloppy, sir.

This is not going in circles, sir, but you still have not retracted your statements.

Until you retract your statements, it will be hard to take you seriously, as you stipulate that light and photons do not travel at c.

Would you be prepared to write a letter to Greene and his publisher that telling him that he is wrong and that photons do not travel at c as you say above?

I am quite amazed that you have never seen the Taylor and Wheeler book on relativity as they say the same things as Greene.

Both Einstein and Greene are right, sir, as are Taylor and Wheeler.

It is you who are wrong.

Einstein, Greene, Taylor, and Wheeler are all accomplished physicists who are to be trusted.

Dear sir--what degrees might you have? What have you published? Perhaps this will help us put your erroneous opinion in perspective.

Thanks!

BE

 

[Doc Al]

Enough already. Thread closed.