The Doppler Effect and the Velocity of Light in Einstein's Theory

[DrChinese]

... This is explained by a moving medium in classical Doppler theory, 1842. There is no “relativity” involved with this phenomenon.

Einstein’s own incorrect relativity ideas kept him blind to this phenomenon and the expansion of the universe. He had to alter his theories after Hubble made his announcement.

It was Newton who first proposed the BB theory, and he turned out to be right.

David, your abuse of history is even worse than your abuse of physics. All physicists consider many ideas and concepts during their liketime. To say that Newton invented or was a strong proponent of the BB is ridiculuous. It is just as absurd to say that Einstein created GR to justify a static universe, or that he was opposed to the BB.

And if you know of somewhere an observer can measure the speed of light to be different than c, well, please enlighten us. If you know of a way to accelerate an object above c, please enlighten us on that as well. Your Nobel awaits.

P.S. How could I have overlooked Doppler's contributions to photon theory, seeing instead Einstein's undeserved contributions? I guess it is that scientific conspiracy thing. Einstein would be amused to find that he was the beneficiary of that conspiracy.

 

[russ_watters]

Uhh, excuse me, but the “gravitational effect” doesn’t cause masses to fly apart. It causes them to collapse in on each other.

?? It doesn't say anything in that quote about masses flying apart. What are you talking about?

Just like with any gravity theory, a spherical universe will collapse, not expand, unless someone adds something like the “cosmological constant” or hypothesizes a “projectile impulse” at the beginning. Neither Einstein nor his equations “predicted” the Big Bang.

So you're saying that its natural to assume that the universe is infinitely old and has been collapsing for an infinite amount of time, but has a finite amount of life left before collapsing completely? Doesn't that seem a little absurd to you (there are a large number of reasons why that is absurd)? Your intuition is pretty much opposite of what physicists have theorized, and for good reason: it leads to an absurd conclusion.

At one time, it was believed that the unvierse was eternal and static. But throwing gravity into that universe would indeed cause contraction: therefore the universe cannot be static. It must either be expanding or contracting. Gravity causes an acceleration that either slows expansion or causes contraction after an expansion phase (or both).

Since the universe cannot be infinitely old, contraction must have been preceded by expansion. And as it turns out, we're still in the expansion phase and we aren't yet sure if it will ever contract again (though its looking like no).

And, for the record, "projectile impulse" did appear in a Google search, but aside from your post, the term is not in reference to an expanding universe

My guess would be you didn't find it because "projectile impulse" implies to me an explosion, the usual misunderstanding/mischaracterization of the Big Bang

David, it appears I gave you too much credit before in assuming you were just arging points you knew to be wrong for fun: you appear now to have some major gaps in your knowledge/understanding and a simple unwillingness to learn. Though it may be more pathological: you abuse/distort/misrepresent/mischaracterize to cover your unwillingness to learn. Disappointing, actually.

 

[russ_watters]

And if you know of somewhere an observer can measure the speed of light to be different than c, well, please enlighten us. If you know of a way to accelerate an object above c, please enlighten us on that as well. Your Nobel awaits.

He has quite a lot actually - all based on the same type of abuses (or, to be fair, common misconceptions). A good one is the "acceleration" of light around a star through gravitational lensing and gravitational doppler shift being a variable C phenomenon.

The most common though I guess is his abuse of frames of reference such as in his statements about >C expansion of the universe.

 

[russ_watters]

Among possibilities are (this list may be exhaustive, given reasonable constraints on matter): an ever contracting universe, an ever expanding universe, and a universe that starts off expanding but eventually contracts.

For my own personal enlightenment, is that a reasonable possibility? I know it doesn't fit with what we observer our own universe to be doing, but hypothetically, could a universe be eternally contracting? It doesn't seem to me that it would be.

 

[DrChinese]

He has quite a lot actually - all based on the same type of abuses (or, to be fair, common misconceptions). A good one is the "acceleration" of light around a star through gravitational lensing and gravitational doppler shift being a variable C phenomenon.

The most common though I guess is his abuse of frames of reference such as in his statements about >C expansion of the universe.

What I meant was:

SR is a theory. All theories have a scope of applicability. So trying to apply it outside of that scope may provide non-sensical results.

SR does say that an observer cannot create an experiment in which the speed of light is measured as other than c. SR does say that you cannot accelerate a galaxy faster than c. However, SR does not say that galaxies cannot be measured to recede from each other faster than c. That is in fact an application of SR outside of its scope.

That is why I said "if you know of somewhere an observer can measure the speed of light to be different than c, well, please enlighten us." This is in response to David's comment against SR: "Its 'speed limit of c' is not correct, and its constancy postulate is not correct." Even if the value of c changed over time, SR would still be correct. Because it is not a postulate of SR that the value of c has always been the same throughout the history of the universe. Just as it is not a postulate of SR than space cannot expand.

 

[Hurkyl]

Here are a few comments by Newton about the ?big bang?, which he simply attributes to a ?Deity?,

http://vms.cc.wmich.edu/~mcgrew/Bent3.htm (Just so others have a reference; you want the other 3 letters, just change that '3' to a '1', '2', or '4')

Here he is basically saying that God must have been responsible for the expansion of the universe and the even distribution of matter.

I can see how the letter could be interpreted as expansion, though it seems a big stretch. In particular, because this phrase appears to be elucidating the statement "... the Hypothesis of Matter?s being at first evenly spread through the Heavens ..." (boldface mine)

But I cannot see how this could be reasonably described as projectile impulse because not only does the deity have to be responsible for the "flying up", but responsible for keeping them falling back down.

I don?t have time to type up all my books and put all their text on the internet.

I'm not asking you to do so; I do have access to a library that might have these things, should I know for what I'm looking. (though I admit it is awfully nice to quote passages; one reason why I strongly prefer internet resources in these debates is so that everyone has access to the references)

With gravity, the universe should contract, not expand

No; you're mixing up first and second derivatives. The rate of growth is what is required, by gravity (and Λ=0), to be decreasing.

Even Newtonian gravity has examples of eternal universal expansion.

But a myth has grown up in recent years that says he added it to keep the universe from ?expanding?. That is silly and it is just one of the many Einstein urban legends that have grown up in the past 30 years.

The focus is on the expansion because, of the cases with Λ=0, that is the one that turned out to be right.

I will note that you do need Λ>0 in order for expansion to be accelerating, a key ingredient of BBT.

but hypothetically, could a universe be eternally contracting?

Einstein's field equations are symmetric under time reversal, aren't they? If they admit an eternally expanding solution, they must also admit an eternally contracting solution. (Of course, this doesn't suggest that there aren't other reasons why an eternally contracting universe is unreasonable. Boy, lots of negatives in that statement )

 

[jcsd]

Yes they are time symmetric, but I don't think it necessarily follows from time symmetry that if in one model there has a certain state at t = 0 and and anothe rat t =infinity then there exists another model that has the same state that the first one had at t = infinity at t' = 0 and the same state as the first one had at t = 0 at t' = infinity because basically the first universe will never be in state t = infinity. In fact I think you find that at t' = 0 you have a universe that is in equilibrium, neither contracting nor expanding,

 

[pallidin]

For the record, references I did find to "projectile impulse" suggest the idea of some object physically imparting momentum to the other object to propel it (or parts of it) into an interesting trajectory. (e.g. Godwin's "Essay XXI of Astronomy")

(Emphasis mine) Hurkyl, perhaps this is not relevant to this discussion, but you statement prompted me to offer this info.
Impulse force propagation does not behave in the same way as non-impulse.
It is very curious that this is the case, and it is not well understood by those researching it(NYU, NASA and others)
Apparently, constant force applied on object contact effects a generally linear propagation(we all know that), whereas the same force, segmented as an impulse, does not do this, rather exhibiting a non-linear contact propagation characteristic.
In general, an object hit by an quick impulse will experience a non-linear, spherical wave propagation of the force imparted to it.
This can lead to somewhat bizarre effects, especially if other "objects" of differring dimensions are involved in the contact scenario.
How this might relate to cosmological influence is unknown(to my knowledge), but certainly worthy of further inquiry.

 

[russ_watters]

What I meant was...

We're on the same page.

 

[Michael F. Dmitriyev]

The velocity of light is unique, absolute and SINGLE speed existing in the nature.

 

[David]

So you're saying that its natural to assume that the universe is infinitely old and has been collapsing for an infinite amount of time, but has a finite amount of life left before collapsing completely?

No.

I never said that.

 

[David]

At one time, it was believed that the unvierse was eternal and static. But throwing gravity into that universe would indeed cause contraction: therefore the universe cannot be static. It must either be expanding or contracting. (or both).

Newton had two other suggestions:

Rotation or infinite.

We see that he was right about “rotation” on the local level, since the galaxies and solar systems rotate.

He was also apparently right about the expansion too.

David, it appears I gave you too much credit before in assuming you were just arging points you knew to be wrong for fun: you appear now to have some major gaps in your knowledge/understanding and a simple unwillingness to learn. Though it may be more pathological: you abuse/distort/misrepresent/mischaracterize to cover your unwillingness to learn.

LOL, you are the guy who told me that Lorentz and Einstein couldn’t have been talking about atomic clocks in their early papers, because you said atomic clock weren’t invented until the 1950s. Then I told you about Maxwell’s mention of natural atomic clocks in 1873.

 

[geistkiesel]

Einstein said in his 1916 book:

”If an observer sitting in the position M1 in the train did not possesses this velocity, then he would remain permanently at M, and the light rays emitted by the flashes of lightning A and B would reach him simultaneously, i.e. they would meet just where he is situated. Now in reality (considered with reference to the railway embankment) he is hastening towards the beam of light coming from B, whilst he is riding on ahead of the beam of light coming from A. Hence the observer will see the beam of light emitted from B earlier than he will see that emitted from A.”

What Einstein means by “he is hastening towards the beam of light coming from B” is that the light beam from the flash at B is converging on the observer that is moving toward B at the relative velocity of c + v, with v being the velocity of the observer toward B. What he means by “he is riding on ahead of the beam of light coming from A” means the light from the A flash is converging on the observer at the velocity of c – v.

This is very simple. The observer-relative speed of the light, relative to the moving observer is NOT “c”, it is NOT constant. It is c + v in one direction and c – v in the other direction.

This is why the Earth sees a blueshift in the light of the star the Earth is moving toward in its revolution around the sun and this is why the Earth sees a redshift in the light of a star the Earth is moving away from during its revolution around the sun. This is caused by the Second Cause of the Doppler effects that I told you about earlier. This is a Doppler Law of Physics. It can not be revoked.

I agree David. Instead of using light use crawling ants for the photons. Einstein would still come up with a loss of simultaneity as he concluded the loss of simultaneity as perceived by the observer on the moving platiofrm was the detection of the ant coming toward him from the front and then the ants comin toward him from the rear, and this is it!.

Of course you will need to restrict your speed to a constant values less than that of the ants so as not to embarrass Professor Einstein, graduate advisor to a host of SR theorists.

 

[quantumdude]

Of course you will need to restrict your speed to a constant values less than that of the ants so as not to embarrass Professor Einstein, graduate advisor to a host of SR theorists.

There's no need for anyone to restrict the speed to something less than the Lorentz invariant speed. Nature will take care of that for you.

 

[geistkiesel]

I’m talking about “physics”, not “science fiction stories”.

Good for you.

The reason the guy on the moving train will see the B flash first is because he is moving toward B and thus he and the light beam from B are converging on each other at the additive light-speed velocity of c + v. That’s a basic law of physics and of nature, and it’s a basic Doppler Law.

Oops, you just slid into sci-fi. Your "basic law of physics" is only an approximation, valid at low speeds.

Oh so SR theory gets to corrupt the basic laws of physics? I thought that even in SR theory the laws of physics were equivalent in all inertial frames.

Prove that what is observed to be true, is false.

Prove that a postulate, a mental arrangement, is superior to a direct observation such as described by David.

Let me see , your proof will start out as "SR theory says . . . ", What was the comment? " ..ooops" , wasn't it?

 

[geistkiesel]

There's no need for anyone to restrict the speed to something less than the Lorentz invariant speed. Nature will take care of that for you.

Tom

I was referring to the substitution of moving ants for the photons, this is why I suggested the volunteered slowing to a speed lless than the ants.

 

[quantumdude]

Oh so SR theory gets to corrupt the basic laws of physics?

No, it does the opposite. It says that the basic laws of physics are the same everywhere, everywhen, for everyone. That stands in stark contradiction to your crackpot idea that the laws of physics in our Earthbound frame are special and somehow Divine.

I thought that even in SR theory the laws of physics were equivalent in all inertial frames.

Now yer getting it.

Prove that what is observed to be true, is false.

That's your objective, not ours.

Prove that a postulate, a mental arrangement, is superior to a direct observation such as described by David.

If you think that David's thought experiment is a "direct observation", then you are just as stupid as he is.

Let me see , your proof will start out as "SR theory says . . . ", What was the comment? " ..ooops" , wasn't it?

No. The proof will start out as, "SR theory says...and let's see what real experiments say in support or denial of that"

That's what all scientists do. You would do well to follow that example, as you don't seem to care if an experiment is real or imagined. All you seem to care about is whether the experiment agrees with your preconceived notions.

edit: fixed a quote bracket

 

[geistkiesel]

No, it does the opposite. It says that the basic laws of physics are the same everywhere, everywhen, for everyone. That stands in stark contradiction to your crackpot idea that the laws of physics in our Earthbound frame are special and somehow Divine.

So if an observation that two photons are emitted simultaneously in a stationary frame and a moving frames say from A and B where M is the midpoint of A and B, just at the instant that identical points on the moving frame are such that A = A', B = B' and M = M' that this simultaeous event in both frames is not a simultaneous event?

I know I have crackpot ideas, WYSIWYG, but the Earth bound frame is an inertial frame is it not? And is not the Earth bound frame a part of the "everywhere" you refer to above?

I would never utter any statement that something is "somehow Divine". If I mentioned anything regarding 'divinity' I might say something "is Divine" and I might say that the laws of physics are Divine, wherever encountered, as in everywhere, but I fail to see any logical thread or relationship, relevance is what I am discussing, that justifies your use of words as you expressed them above.

Is it an old intuitive threat to professional security considerations that motivates your rather unscientific mode of response?

Special relativity is your mantra isn't it?

If you think that David's thought experiment is a "direct observation", then you are just as stupid as he is.

The experiments being discussed are as real as Einstein's when he presented his gedunkens. I would rather be as stupid as David than to be as stupid as you. his mind seems to work as a mind. It has the characteristics of being free, or working to that end. I don't recognize the characteristics of mind iassociated with your post. Brat robot is more what I observe.

quoting geistkiesel
No. The proof will start out as, "SR theory says...and let's see what real experiments say in support or denial of that"

That's what all scientists do. You would do well to follow that example, as you don't seem to care if an experiment is real or imagined. All you seem to care about is whether the experiment agrees with your preconceived notions.

edit: fixed a quote bracket

So one gedunken cannot be used to counter another gedunken? That is the scientific rule where you come from? I would do well to follow that example?

So David's and Geistkiesel's observations don't wash in a mind soaked in SR theory? That doesn't sound like a Divine situation to me. I am going to speak to someine in authority about that, as soon as I can get 'his' attention, if you know what I mean. I'll get back to later on this.

When you wake up Tom everything will seem like a bad dream, but the bogie man will be gone, the things that go bump in the night will be no more and you can begin to live again, free at last.

 

[russ_watters]

The experiments being discussed are as real as Einstein's when he presented his gedunkens.

Tom pointed this out, but didn't explain (it really should be self-evident). Einstein's thought experiments were conceived as hypothetical examples in order to explain his theory, just as yours and David's are. The difference is that since it was concieved, Relativity has been substantiated by mountains of real, scientific evidence. Your ideas, on the other hand, exist only in your mind.

So one gedunken cannot be used to counter another gedunken? That is the scientific rule where you come from? I would do well to follow that example?

That's correct. Since a thought experiment isn't real, it doesn't prove or disprove anything.

 

[quantumdude]

So if an observation that two photons are emitted simultaneously in a stationary frame and a moving frames say from A and B where M is the midpoint of A and B, just at the instant that identical points on the moving frame are such that A = A', B = B' and M = M' that this simultaeous event in both frames is not a simultaneous event?

You're asking me if a statement if the form, "If p, then p" is true. Of course it is, because it is an empty tautology.

I know I have crackpot ideas, WYSIWYG, but the Earth bound frame is an inertial frame is it not? And is not the Earth bound frame a part of the "everywhere" you refer to above?

The Earthbound frame is not inertial, but it is close enough. And yes, it is part of "everywhere".

I would never utter any statement that something is "somehow Divine". If I mentioned anything regarding 'divinity' I might say something "is Divine" and I might say that the laws of physics are Divine, wherever encountered, as in everywhere, but I fail to see any logical thread or relationship, relevance is what I am discussing, that justifies your use of words as you expressed them above.

You fail to see a lot of things.

Insisting that the laws of physics take their "textbook form" on Earth and insisting that the Lorentz transformation is wrong is logically equivalent to insisting that the laws of physics are the way we know them only on Earth.

Is it an old intuitive threat to professional security considerations that motivates your rather unscientific mode of response?

Just how would you even know what a scientific mode of response is? You don't even know the difference between a thought experiment and a real experiment.

Special relativity is your mantra isn't it?

No, physics is.

The experiments being discussed are as real as Einstein's when he presented his gedunkens.

Well, we agree on that much: Neither one is real at all.

I would rather be as stupid as David than to be as stupid as you.

Suit yourself. Suffice it to say that you got your wish.

his mind seems to work as a mind. It has the characteristics of being free, or working to that end.

Yes, his mind is "free" alright. It is so "free" that it is unconstrained by logic, science, mathematics, or evidence.

I don't recognize the characteristics of mind iassociated with your post. Brat robot is more what I observe.

Your vision is obviously clouded then. As I said, there is a difference between real experiments and thought experiments, which you don't see.

So one gedunken cannot be used to counter another gedunken? That is the scientific rule where you come from? I would do well to follow that example?

You say that to mock me, but the statement is correct. Thought experiments cannot disprove theories. Period.

Scientific theories are deductive arguments built up from statements which are the conclusions of inductive arguments. Those inductive arguments are based on experimental evidence. Given that, you can disprove a theory in one of two ways:

1. Show that the theory is not deductively valid.
2. Show that one or more of the premises is false.

#1 can be done with mathematics and #2 can be done with evidence. Neither can be done with a thought experiment.

So David's and Geistkiesel's observations don't wash in a mind soaked in SR theory?

What observation?

That doesn't sound like a Divine situation to me. I am going to speak to someine in authority about that, as soon as I can get 'his' attention, if you know what I mean. I'll get back to later on this.

Don't bother. It won't be worth reading anyway.

When you wake up Tom everything will seem like a bad dream, but the bogie man will be gone, the things that go bump in the night will be no more and you can begin to live again, free at last.

Get a clue. You haven't referred to a single real experiment. All you have referred to are thought experiments, which you falsely believe are just as good. They aren't.

You know, you and David would both do well to read posts from people such as Wisp and Yogi. They aren't convinced of SR either, but they refer to real, actual, factual experiments that have taken place in the physical world, not in warped minds. While I don't agree with them, it's not as though I dismiss anti-SR posts out of hand. I don't. I acknowledge that there are competent critics of SR out there.

You and David just aren't among them.

 

[Michael F. Dmitriyev]

Velocity of light is absolute and SINGLE velocity existing in the universe at microlevel.
Relativity appears at macrolevel.

 

[ram2048]

but he's talking about some superluminal things emitting light back to earth, which i find intriguing

if something going 4c to the left "emits" a photon to the right isn't that photon still going 3c to the right?

this slowing down to 0 speed then accelerating towards the left until it hits c in that direction is just odd

i don't think i can buy that

how about the one theory where light has a wave component and a matter component? Using that one the matter part could be emitted to the left at c, but the wave part is stretched to the magnitude of 3c to the right (redshifting) due to superluminal emitter...

this seems consistant

btw: i believe in einstein's setup he WAS referring to doppler shift, not relativistic observation. it seems way more simple than relativity.

 

[geistkiesel]

Velocity of light is absolute and SINGLE velocity existing in the universe at microlevel.
Relativity appears at macrolevel.

Michael,
I have a problem. I am under the belief that an electromagnetic sphere whose radius is expanding at velocity c will have a diameter of 2c after 1 second. This sounds suspiciously close to the statement that the photons moving in opposite directions to each other are expanding at a rate of 2c. I was told in no uncertain terms that I erred, but I ws not given any direction to solving my dilemma.

I want to believe llike everybody else. What is the rroof? That the sphere is expanding at a rate of 2^1/2c?, which is what I was told. Do you know?

 

[Michael F. Dmitriyev]

A photon being a bit of matter can be rewriting at a new place with the maximal speed.
The particles, as a words, sentences and the combination of words and sentences demands a greater time of rewriting according to their length. It is a most simple way to understand why any material object cannot exceed the velocity of light.

 

[Michael F. Dmitriyev]

Michael,
I have a problem. I am under the belief that an electromagnetic sphere whose radius is expanding at velocity c will have a diameter of 2c after 1 second. This sounds suspiciously close to the statement that the photons moving in opposite directions to each other are expanding at a rate of 2c. I was told in no uncertain terms that I erred, but I ws not given any direction to solving my dilemma.

I want to believe llike everybody else. What is the rroof? That the sphere is expanding at a rate of 2^1/2c?, which is what I was told. Do you know?

Relativity cannot be applied to the light.

 

[Doc Al]

I have a problem. I am under the belief that an electromagnetic sphere whose radius is expanding at velocity c will have a diameter of 2c after 1 second. This sounds suspiciously close to the statement that the photons moving in opposite directions to each other are expanding at a rate of 2c. I was told in no uncertain terms that I erred, but I ws not given any direction to solving my dilemma.

As I mentioned in another thread, there is no problem whatsoever in having someone observe two photons separating at a rate of 2c. In fact, if the photons are moving in opposite directions, relativity insists that this be the case.

Note that the observed speed of each photon is still c.

 

[russ_watters]

As I mentioned in another thread, there is no problem whatsoever in having someone observe two photons separating at a rate of 2c. In fact, if the photons are moving in opposite directions, relativity insists that this be the case.

Note that the observed speed of each photon is still c.

Note also that an observer traveling just behind one of those photons, just under C, still sees each photon traveling at C.

"Separation velocity" isn't a velocity that has any SR implications. Its just geometry.

If I may change the thought experiment slightly to make it resolvable...

Take 3 observers, x, Y, & Z starting out next to each other:

XYZ

X and Z move away from Y at just under the speed of light.

X<----Y---->Z

Observer X measures both Y and Z to be moving away from him at just under the speed of light - Z is just a little closer to the speed of light than Y. Observer Z measures the same thing about X and Y. Observer Y measures both to be just under C.

Geometrically adding the speeds gives X and Z a "separation velocity" of just under 2C from the frame of reference of Y. But that doesn't in any way imply that Z or X will measure their own velocity with respect to each other at just under 2c.

 

[Doc Al]

"Separation velocity" isn't a velocity that has any SR implications. Its just geometry.

Right. Don't confuse this "separation velocity" with a relative velocity.

As another example: Someone (observer A) observes two rockets (B and C) traveling in opposite directions, each with speed 0.9c. The "separation velocity" of the two rockets, as observed by A, is 1.8c. But the speed of C as observed by B (the velocity of C with respect to B) is only 0.994c.

 

[David]

Note also that an observer traveling just behind one of those photons, just under C, still sees each photon traveling at C.

Einstein revoked his “constancy” postulate in 1912. Why don't you know this? Haven't you read his 1912 papers?

 

[David]

Right. Don't confuse this "separation velocity" with a relative velocity.

As another example: Someone (observer A) observes two rockets (B and C) traveling in opposite directions, each with speed 0.9c.

Lorentz said that based on electrodynamics, there is a “speed limit” in local gravity fields. You can’t accelerate a rocket in the solar system to .9c. What you are posting here is urban legend. Why does Bernhardt Media promote urban legends?

 

[David]

Michael,

I want to believe llike everybody else.

You want to be brainwashed about relativity “like everybody else”??

Go out and by the complete 8 Volume set of “The Collected Papers of Albert Einstein”, Paperback English edition, Princeton Press, and you will see that these “mentors” don’t know what they are talking about.

Einstein revoked his “constancy” postulate in 1912. In 1907 he said that objects really don’t “geometrically” contract due only to “relative motion”. The distant galaxies exhibit redshifts that indicate they are moving at 2c and 3c relative to the earth. What these guys here are pushing is a bunch of rumors and urban legends suitable for teenagers.

 

[David]

I agree David. Instead of using light use crawling ants for the photons. Einstein would still come up with a loss of simultaneity as he concluded the loss of simultaneity as perceived by the observer on the moving platiofrm was the detection of the ant coming toward him from the front and then the ants comin toward him from the rear, and this is it!.

Of course you will need to restrict your speed to a constant values less than that of the ants so as not to embarrass Professor Einstein, graduate advisor to a host of SR theorists.

When Einstein said, “Events which are simultaneous with reference to the embankment are not simultaneous with respect to the train, and vice versa (relativity of simultaneity).”

But everybody knew that already. This is why the railroads divided the country up into four time zones in the 19th Century, to try to bring some simple form of “simultaneity” to the rail system. Before then, everybody was using local time set at noon by sundials in every city, and railroad conductors had to convert railroad time into local time, because the two lacked “simultaneity”.

In 1916 he said, “Now in reality (considered with reference to the railway embankment) he is hastening towards the beam of light coming from B, whilst he is riding on ahead of the beam of light coming from A. Hence the observer will see the beam of light emitted from B earlier than he will see that emitted from A.”

Everybody knew that already too. That’s about as obvious as saying, “The front of the train will arrive at the station before the rear of the train.”

If we are closer to one of two simultaneous events, we will receive light or sound signals from the closest event first. If we are right in between the two simultaneous events, we will receive light or sound signals from both events at the same time. Doh. People have known this for thousands of years. People have known that all kinds of clocks slow down due to different natural effects, and they've known that for thousands of years.

This Einstein stuff is over promoted by guys who like to think they are "as smart as Einstein". It's a cult.

This reminds me of the movie, “Being There”. Review comments: “It is hysterically funny to see how the always immaculately dressed, in formal attire, Chance rises to national prominence, due to people reading more into his stated "few simple truisms," and then giving the credit of a deep thinker to Chance, who is simply stating what he understands, in a calm, confident, positive, reassuring manner.”

“Benjamin Rand takes a shine to the person he believes is "Chauncey Gardner;" a simpleton he takes as an enigmatic and deeply contemplative thinker. Rich and powerful Ben introduces him to the President, to whom Chance makes cryptic comments that the president takes as a wise analogy of the seasons and the economy. A national TV appearance spreads "Chauncey's" fame. The only person who knows him, the "old man's" kindly maid, sizes up Chance's words: gobbledygook. The rich and powerful assume "Chauncey's" simple words imply great intelligence. Ben's doctor suspects that Chauncey may in fact have a child's mind, but is not certain.”

 

[David]

There's no need for anyone to restrict the speed to something less than the Lorentz invariant speed. Nature will take care of that for you.

Hey, Mr. X-Ray, look at this:

“Thus for the largest known redshift of z=6.3, the recession velocity is not 6.3*c = 1,890,000 km/sec. It is also not the 285,254 km/sec given by the special relativistic Doppler formula 1+z = sqrt((1+v/c)/(1-v/c)). The actual recession velocity for this object depends on the cosmological parameters, but for an OmegaM=0.3 vacuum-dominated flat model the velocity is 585,611 km/sec. This is faster than light.”

http://www.astro.ucla.edu/~wright/doppler.htm

Hey, the 99 year old hoax is over.

 

[David]

. In fact, if the photons are moving in opposite directions, relativity insists that this be the case.

No it doesn’t. Read Einstein’s 1911 and 1916 papers. Read his 1912 papers. He said light speed is slower than “c” inside a gravity field. He said that light speed is NOT “constant”.

Look, you’ve got to spend more money on relativity books than you spent on the two $9.95 books, “The Principle of Relativity” and “Relativity: The Special and General Theory”.

You’ve got to read some of Einstein’s subsequent papers. You’ve got a $19.90 “relativity” education, and it shows.

 

[ahrkron]

Hey, Mr. X-Ray, look at this:

“Thus for the largest known redshift of z=6.3, the recession velocity is not 6.3*c = 1,890,000 km/sec. It is also not the 285,254 km/sec given by the special relativistic Doppler formula 1+z = sqrt((1+v/c)/(1-v/c)). The actual recession velocity for this object depends on the cosmological parameters, but for an OmegaM=0.3 vacuum-dominated flat model the velocity is 585,611 km/sec. This is faster than light.”

http://www.astro.ucla.edu/~wright/doppler.htm

Hey, the 99 year old hoax is over.

The same page, from UCLA, has a link from the phrase "faster than light" that takes you to an explanation of why this does not violate SR. You just chose not to see it.

For others that may wonder how that works, here is the link.

 

[ahrkron]

No it doesn’t. Read Einstein’s 1911 and 1916 papers. Read his 1912 papers. He said light speed is slower than “c” inside a gravity field. He said that light speed is NOT “constant”.

Even assuming that you were not quoting papers from the time GR was under development, nowhere near its final form, where did Doc Al or geistkiesel mention anything about GR, or a gravity field?[/color]

Also, you would be much better off dropping your "$9.95" argument. As some of us have pointed out to you already, getting a real education on current physics takes quite a bit more (money, time and effort) than those involved in buying and reading the collected papers of AE, who died in 1954.

And, as you say, it shows.

 

[russ_watters]

Einstein revoked his “constancy” postulate in 1912. Why don't you know this? Haven't you read his 1912 papers?

What does this discussion have to do with Einstein? He's dead.

 

[ahrkron]

When Einstein said, “Events which are simultaneous with reference to the embankment are not simultaneous with respect to the train, and vice versa (relativity of simultaneity).”

But everybody knew that already. This is why the railroads divided the country up into four time zones in the 19th Century, to try to bring some simple form of “simultaneity” to the rail system[/color]. Before then, everybody was using local time set at noon by sundials in every city, and railroad conductors had to convert railroad time into local time, because the two lacked “simultaneity”.

Wow! This is just beautiful. I'm sorry David, but as I said, "it shows". You do not seem to understand what the issue with simultaneity is.

 

[ahrkron]

In 1916 he said, “Now in reality (considered with reference to the railway embankment) he is hastening towards the beam of light coming from B, whilst he is riding on ahead of the beam of light coming from A. Hence the observer will see the beam of light emitted from B earlier than he will see that emitted from A.”

Everybody knew that already too. That’s about as obvious as saying, “The front of the train will arrive at the station before the rear of the train.”

If we are closer to one of two simultaneous events, we will receive light or sound signals from the closest event first. If we are right in between the two simultaneous events, we will receive light or sound signals from both events at the same time. Doh. People have known this for thousands of years.

Again, as you did with your quote of UCLA's page, you are stopping just before things get interesting.

Of course people knew about sound arriving first from the closest source. The thing that changes all else is the fact that, unlike sound, light will be measured to have the same speed[/color] by both observers. From there, a little algebra takes you to Lorentz transformations, showing, along the way, their logical linkage to a measured phenomenon (the constancy of the speed of light).

People have known that all kinds of clocks slow down due to different natural effects, and they've known that for thousands of years.

Sure, but nobody before the uderstanding of Lorentz Transformations was able to correctly predict[/color] the slowing down caused by relative motion.

Your (failed attempt of a) rebuttal is akin to this:

[someone] Mr. X has discovered that gene Y is the cause of cancer.

[you] Nay! People have known that all kinds of persons die due to different natural effects, and they've known that for thousands of years.

 

[geistkiesel]

David said:
In 1916 he said, “Now in reality (considered with reference to the railway embankment) he is hastening towards the beam of light coming from B, whilst he is riding on ahead of the beam of light coming from A. Hence the observer will see the beam of light emitted from B earlier than he will see that emitted from A.”

Everybody knew that already too. That’s about as obvious as saying, “The front of the train will arrive at the station before the rear of the train.”

If we are closer to one of two simultaneous events, we will receive light or sound signals from the closest event first. If we are right in between the two simultaneous events, we will receive light or sound signals from both events at the same time. Doh. People have known this for thousands of years.

Again, as you did with your quote of UCLA's page, you are stopping just before things get interesting.

Of course people knew about sound arriving first from the closest source. The thing that changes all else is the fact that, unlike sound, light will be measured to have the same speed by both observers. From there, a little algebra takes you to Lorentz transformations, showing, along the way, their logical linkage to a measured phenomenon (the constancy of the speed of light).

I agree with David!
The Einstein Train gedanken from another view. Read at your peril.
______________________________________________
All moving frame values are non-primed with the exception of M’, the consistent location of the observer O in the moving frame.

At no time is there an inference that M’ was at the midpoint of the A and B photons emitted in the stationary frame.

To demonstrate the following:

Einstein’s moving train calculation indicating when the oncoming B photon is detected at t1 the A photon was located at a position consistent with –t1. Said in other words, as t1 is determined from t0 which locates M’ at t0, the A and B were equidistant to M’(t0) when t = t1.

Proof:
A moving observer located at M’ on a moving frame passes through the midpoint M of photon sources located at A and B in the stationary frame just as A and B emit photons. M’ is moving along a line connecting A and B, toward B.

At this instant the moving source t = t0. Later the moving observer detects the photon from B at t1, and later the photon from A at t2. The observer has measured her velocity wrt the stationary frame as v. Determine the position of the A photon at tx in terms of t0, t1, t2, and v when the B photon was detected at t1.

The photon from A must reach the position of M’ when t = t2. Therefore, the distance traveled by the A photon during Δt = t2 – t1, is Δtc. This is equal to the distance cΔt = vΔt + vt1 + vtx . Now we rearrange somewhat to arrive at, vtx = vΔt – cΔt + –vt1. Now as vΔt - cΔt is just -vtx - vt1

vtx = -vtx - vt1 – vt1

2tx = -2t1

tx = -t1

Therefore, in the moving frame the photon from A and the photon from B were equidistant from M’(t0) at t1.

 

[Ingvar Astrand]

“Thus for the largest known redshift of z=6.3, the recession velocity is not 6.3*c = 1,890,000 km/sec. It is also not the 285,254 km/sec given by the special relativistic Doppler formula 1+z = sqrt((1+v/c)/(1-v/c)). The actual recession velocity for this object depends on the cosmological parameters, but for an OmegaM=0.3 vacuum-dominated flat model the velocity is 585,611 km/sec. This is faster than light.”

To David (I like your energy) and other interested.

Redshift is not a recession velocity question. The kinematic mechanism behind is the entropy-effect that Clausius coined for the notion he invented when he searched the cause and reason to why heat-radiation moved to equilibrium.

Planck and his colleagues found the cause and reason but didn’t understand how to interpret the constant fractional increasing change between the electrodynamical wave-units. Desperate Planck tried to interpret the value that was measured as differences between wavelengths as continuing change in energy. To do so he inverted the fractional value to the temperature’s change over the frequency spectrum. Wien and Stefan–Boltzmann laws have showed that there is a relation between temperature and wavelengths, but Planck had got lost in his derivation. Einstein later suggested (postulated) that this mathematical artifact “must” be interpreted as quantum-unit.

Planck’s measured value 6.626 x 10^-34 tells us how much an electrodynamical wave is extended from wave to wave or proportional to the distance. This is the simple formula (redshift = constant x distance). So the distance to this 6.3 (6.28) quasar that is redshifted from (1216 to 7636 Angstrom) is: (6.420 x 10^-10 km) / (6.626 x 10^-34) = 9.7 x 10^23 km. The distance defined as light-years -- that is 0.95 x 10^13 km per light-year -- to this 6.28-quasar is near 1000 billion light years.

A quasar’s energy that we receive is proportional to the redshift (energy = z^4). So this 6.28 quasar emits at the wavelength 1216 Angstrom 1555 times more energy than we receive at 7636 Angstrom. This energy drives the light (waves) forward.

When electrodynamic waves increase their lengths their velocities also increase to this simple formula [c + (2c x redshift)^-2]. So the 6.3 quasar’s wavelength of 7636 Angstrom that we receive moves [(2 x 3 x 10^5 x 7.636^-10)^-2] km/s = 0.045 km/s faster than c.

The light-spectrum that we se as stroboscope-frozen moves at the velocity of light, but we can not see that the waves increase their speed with their wave-displacement. But we can understand it when we see the increasing wavelengths between the water-rings from the pebble that is thrown in the water.

Ingvar Astrand, Sweden

 

[terrabyte]

Note also that an observer traveling just behind one of those photons, just under C, still sees each photon traveling at C.

"Separation velocity" isn't a velocity that has any SR implications. Its just geometry.

If I may change the thought experiment slightly to make it resolvable...

Take 3 observers, x, Y, & Z starting out next to each other:

XYZ

X and Z move away from Y at just under the speed of light.

X<----Y---->Z

Observer X measures both Y and Z to be moving away from him at just under the speed of light - Z is just a little closer to the speed of light than Y. Observer Z measures the same thing about X and Y. Observer Y measures both to be just under C.

Geometrically adding the speeds gives X and Z a "separation velocity" of just under 2C from the frame of reference of Y. But that doesn't in any way imply that Z or X will measure their own velocity with respect to each other at just under 2c.

Hmm?

Assuming a start of:

XYZ

and then a process of:

X<------Y------>Z

given 1 second with seperations speeds of c all around X is 300,000 from Y which is 300,000 from Z.

i'm not seeing how you're saying from X's perspective Y is 290,000 from X and Z is 300,000 from X :|

are you sure you know what you're doing?

 

[zoobyshoe]

Einstein revoked his ?constancy? postulate in 1912. In 1907 he said that objects really don?t ?geometrically? contract due only to ?relative motion?.

David,

If you could quote these two things verbatim for us, I think it would be of great interest to everyone.

Were these published statements, or things he said in letters, or just things he had in his notes?

 

[russ_watters]

given 1 second...

1 second according to whom? X,Y, and Z will not agree on when that second has passed.

And those distances: according to whom? X,Y, and Z will not agree on the distances traveled.

 

[jcsd]

Hey, Mr. X-Ray, look at this:

“Thus for the largest known redshift of z=6.3, the recession velocity is not 6.3*c = 1,890,000 km/sec. It is also not the 285,254 km/sec given by the special relativistic Doppler formula 1+z = sqrt((1+v/c)/(1-v/c)). The actual recession velocity for this object depends on the cosmological parameters, but for an OmegaM=0.3 vacuum-dominated flat model the velocity is 585,611 km/sec. This is faster than light.”

http://www.astro.ucla.edu/~wright/doppler.htm

Hey, the 99 year old hoax is over.

It's this kind of buffonery that makes it obvious, that it's you're understanding of special relativity not special relativity itself that is flawed. Notrice that the special relativistic interpreation gives an answer of below c, in fact it is impossible using purely special rleatyivity to interpet a redshift as a relative velocity of above c, if this is the case you start to get imagibnary numbers for physical quantities that can be directly observed.

The effect is general relativistic

 

[terrabyte]

...that doesn't sound very convenient at all.

supposing we have a "stationary" length of matter. 600,000 km long with huge metal plates on either end. we have a light source at the midpoint Y. given 1 second "according to Y" will the light have reached both the plates on either ends 300,000 km distant? (for simplicity assume 300,00km/s is light speed)

 

[Doc Al]

supposing we have a "stationary" length of matter. 600,000 km long with huge metal plates on either end. we have a light source at the midpoint Y. given 1 second "according to Y" will the light have reached both the plates on either ends 300,000 km distant? (for simplicity assume 300,00km/s is light speed)

Observers in the Y frame (who are at rest with respect to those metal plates) would say yes. So, according to Y frame measurements, the light arrives at each plate simultaneously. Of course, observers in other frames (that are moving with respect to Y) will measure the light to arrive at each plate at different times according to their clocks.

 

[terrabyte]

so you're saying the moving people's clocks are screwed up, but in reality the light does reach the plates in 1 second...

 

[Doc Al]

time is frame dependent

so you're saying the moving people's clocks are screwed up, but in reality the light does reach the plates in 1 second...

Not at all. Everyone is perfectly entitled to view themselves to be at rest and the others as moving. No one is entitled to say that they are the one who is really at rest. Measurements of time, length, and simultaneity are frame-dependent. Measurements made by X or Z are just as useful and valid as any made by Y.