Einstien . . .wrong ??

Obviously this was inspired by the "Relativity" thread. I have heard it said that it has been proven that Einstien's Theory of Relativity has been proven to be incorrect. Is this so ? If so, how ? His theory was a subject of great study of mine for a long time, I truly wish to know the straight dope about this. Thanks

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"A single lifetime, even though entirely devoted to the sky, would not be enough for the investigation of so vast a subject." - Seneca

[knappy]

I haven't heard of any widely accepted disproof, but if you find one, please run it through http://math.ucr.edu/home/baez/crackpot.html first. (And watch #8, please.)

[Keeves]

Einstein was no more wrong than Newton was.

That is, they both made great strides in improving what came before them, yet their own discoveries were refined and improved by those who came later.

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Remember, you are unique.
Just like everyone else.

[Rainbowcsr]

I always have had a hard time with his theory of relativity, in that the closer you approach the speed of light, the more time distorts. I read about how it was proven by clocks on the Shuttle, but I still disagreed with it, but not being mathematically inclined, had no way to prove it.

In my own theory, there is a universal time, which affects all of the universe, depending upon ones view. Like if it is 12 am where you are on Earth, then it is 12 am to you and your vicinity. Now, eliminate the newly invented time zones -- originally created by the rail roads to make things easier -- and whisk yourself instantaneously out to the orbit of Pluto and look back. Technically -- it is still 12 for you and that zone of Earth. (Not including any milliseconds or microseconds here) Instead of going to the orbit of Pluto, instantaneously whisk yourself to Andrometer. Again, it is STILL 12 for you and that spot on Earth.

Carry it a step further, and from that spot on Earth, instead of Andrometer, whisk yourself to the ends of the Universe - if any -- and look back. Somewhere in there is Earth and it is still 12 there and for yourself and, according to you, 12 for the entire universe.

I'm a big science fiction reader and there aren't too many of those writers to agree with the theory of relativity either. There is a flaw in it somewhere, but I'm not smart enough to figure it out.

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What? Me worry?'

[Yue Han]

a) It's Andromeda, no Adrometer.

b) So, despite scientific evidence, you don't believe in relativity, just because it's counterintuitive and science fiction writers don't use it?!

c) You don't know what relativity is, judging by your example.

You have destroyed what little faith I had in the average intelligence of the human race.

--John

[RussellM]

Rainbowcsr
I read about how it was proven...but I still disagreed with it
It is clear that reasoned scientific debate is alive and well.

When you suggest that there aren't too many of those [science fiction] writers to [who?] agree with the theory of relativity, do you mean that they actually do not agree with it, or they find it inconvenient for the purposes of Science Fiction? I can only assume that you are aware of the importance of the word fiction, here and near Andromeda.

[Zor]

Come on, Yue Han, you didn't have to be mean :)

For those of you that disagree with relativity, but can't really come up with a reason, I suggest you read the FAQ of relativity here...

http://math.ucr.edu/home/baez/physics/relativity.html

This is the same site which Knappy's crackpot index is on by the way...

[ZenBeam]

Knappy, I like that crackpot index.

In #17, "10 points for each favorable comparison of yourself to Einstein, or claim that special or general relativity are fundamentally misguided (without good evidence)." You should get extra credit for both comparing yourself to Einstein and claiming relativity is misguided. :)

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It is too clear, and so it is hard to see.

[Padeye]

Rainbow, the time dilation effect has been observed on mere airplanes. IIRC a 747 flown around the world so you don't need a shuttle. In fact an amateur astronomer can observe the effect directly because the orbit of Mercury is not "correct" according to pure Newtonian laws of motion.

As Keeves said Newton wasn't wrong. He did an excellent job of describing most of what we can observe. Relativity takes it much further but it takes a different understanding of what time, space, matter and energy are.

There is a lot to understand about relativity so it naturally seems counterintuitive if you only look at one part of it.

[Padeye]

Originally posted by knappy:
I haven't heard of any widely accepted disproof, but if you find one, please run it through http://math.ucr.edu/home/baez/crackpot.html first. (And watch #8, please.)

You should have posted a warning Knappy. I programmed the crackpot index in visual basic and scaned my copy of Velikovsky's Worlds in Collision into it. The resulting cataclysm flattened cubicle walls in a 20 yard radius.

FWIW I was not kidding about having the book :D

[RealityChuck]

I'm a big science fiction reader and there aren't too many of those writers to agree with the theory of relativity either.

Speaking as a science fiction writer, nearly everyone in the field accepts relativity. We invent ways to get around it (warp drive, wormholes, etc.), but the last author who didn't agree with it was probably Doc Smith (and he probably knew he was cheating; either that, or too many donuts).



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"East is east and west is west and if you take cranberries and stew them like applesauce they taste much more like prunes than rhubarb does." -- Marx

Read "Sundials" in the new issue of Aboriginal Science Fiction. www.sff.net/people/rothman (http://www.sff.net/people/rothman)

[douglips]

In my own theory, there is a universal time, which affects all of the universe, depending upon ones view. Like if it is 12 am where you are on Earth, then it is 12 am to you and your vicinity.

Your theory has been proven wrong. Leaving aside any ad hominem remarks such as John provided, here is what special relativity says about your 'time in my vicinity' theory:


If you have a clock in your house and a clock 5 miles away in your friends house, and they are perfectly synchronized, and you can watch them both (maybe closed-circuit TV) then you can verify that the time is the same in your house and your friends house.


So far so good. Also, if you have a friend on Pluto or in Andromeda who is not moving relative to your position on the earth, and they wait the requisite amount of time for the TV transmission of your clocks to reach them, they'll agree that the clocks read the same. Let's leave out the 'whisk yourself instantaneously' thing for now.


So far, still so good. Now, what happens if I fly by in my spaceship at nearly the speed of light? I'll look at your clock and at your friend's clock and see different times. That's what relativity says.


This fundamentally disagrees with your idea of a universal time - relativity says that simultanaity is not identical in all inertial reference frames.


We can do the experiment, and we have, and your theory is not supported while Einstein's is.

[KeithB]

Most science fiction writers ignore relativity because it is a difficult subject. Most just invent plot devices to get around it. Heinlein wrote a whole novel around the twin paradox.

Actually, Einstein was wrong for most of his life. None of his ideas about the "grand unification theorem" panned out.

However, he was dead nuts right about quanta, special relativity and general relativity. *NO*, and I repeat *NO* experiment has shown it to be wrong. Including ones that set out specifically to prove it wrong. In a true test of it, particle physicists have to take it into account daily in order to correctly interpret cloud chamber results.

Oh, he was also wrong about quantum mechanics, in much the same way that most crackpots don't accept relativity. He *intuited* that nature would not be as random as QM indicated it was. "God would not play dice with the universe."

[JonF]

I think it's fair to say that Einstein's relativity theory is known to be lacking as a fundamental explanation of how the universe works. Quantum electrodymanics and relativity disagree in some fundamental areas. QE makes an incredible number of incredibly correct predictions under certain circumstances, and relativity makes an incredible number of incredibly correct predictions under other circcumstances. So the next problem is to come up with a theory which includes them both.

Please don't confuse the fact that relativity is incomplete with the fact that it is correct under a large number of known circumstances. The theory that supplants relativity will of necessity make the same predictions as relativity in most cases. Relativity has not been proven incorrect, and will not be proven incorrect, in the areas where it is known to apply.

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jrf

[Yue Han]

I'd like to point out that ad hominem attacks would be making remarks about Rainbow's personality or appearance and using those as "evidence" against his theory.

I was insulting, but I didn't claim that he was wrong because of anything personal about him. It was still rude and uncalled-for. I was tired and his post showed an appalling lack of logic.

I apologize.

--John

[RM Mentock]

Originally posted by <font color=#FF30c0>KeithB</font>:
Actually, Einstein was wrong for most of his life. None of his ideas about the "grand unification theorem" panned out.

:confused: That makes all of us wrong for all of our lives, as our ideas about TOEs haven't panned out either. :)

Originally posted by <font color=#FF30c0>KeithB</font>:
Oh, he was also wrong about quantum mechanics, in much the same way that most crackpots don't accept relativity. He *intuited* that nature would not be as random as QM indicated it was. "God would not play dice with the universe."

That's still being debated. His objection wasn't against quantum mechanics, just the "Copenhagen" interpretation of quantum mechanics. His ideas are still leading the charge against the Copenhagen interpretation, and some scientists feel the Copenhagen interpretation is losing.
<font color=#FCFCFC>----------------
rocks</font>

[emarkp]

If no one else is going to answer the question, I'll share what I've found. It turns out there was quite an article published at the end of 1998 that suggests rather strongly that Special Relativity is wrong. You can find a reference to the article and an overview at: http://209.67.208.207/499TAS/bethell.htm

The text of the article can be found at: http://www.ldolphin.org/vanFlandern/gravityspeed.html

Basically, I think this fellow puts forth a pretty good argument. All of the objections I had were neatly addressed in the article.

SR is the bit about time slowing down as you speed up, and includes the idea that nothing, not even information, can travel faster than the speed of light.

Van Flandern shows that gravity must travel at least 20 billion times the speed of light and may well be instantaneous. Take a peek at both links and see what you think.

[KeithB]

However, people have done a lot of good things with the Copenhagen interpretation, which is my test of a good theory. My point was that he used his *intuition* to pronounce judgement on the theory, not facts. In "The Making of the Atomic Bomb" Rohdes talks about a "Solvay Conference" in Brussels, 1927. I quote at length:

'Einstein attended as did Bohr, Max Planck, Marie Curie, Hendrick Lorentz, Max Born, Paul Ehrenfest, Erwin Schrodinger, Wolfgang Pauli, Werner Heisenberg and a crowd of others. "We all stayed at the same hotel," Heisenberg remembers, "and the keenest arguments took place, not in the conference hall but during the hotel meals. Bohr and Einstein were in the thick of it all."

Einstein refused to accept the idea that determinism on the atomic level was forbidden, that the fine structure of the universe was unknowable, that statistics rule. "'God does not throw dice' was a phrase we often heard from his lips during these discussions," writes Heisenberg. "And so he refused point-blank to accept the uncertainty principal, and tried to think up cases where it would not hold." Einstein would produce a challenging thought-experiment at breakfast, the debate would go on all day, "and, as a rule, by suppertime we would have reached a point where Niels Bohr could prove to Einstein that even his latest experiment failed to shake the uncertainty principal. Einstein would look a bit worried, but by next morning he was ready with a new imaginary experiment more complicated than the last." This went on for days, until Ehrenfest chided Einstein -- they were the oldest of friends -- that he was ashamed of him, that Einstein was arguing against quantum theory just as irrationally as his opponents had argued against relativity theory. Einstein remained adamant...'
(Any typos mine)

I may be wrong, but arguing against the Uncertainty Principal is more fundamental than disagreeing with the Copenhagen interpretation.

[douglips]

emarkp
It's the Evil Mark Ping!

Remember me? CS60C? OCF?

[trouts1]

emarkp

Interesting link above. At first thought it foolish (sorry) but consulted the relativity FAQ as a head check and found there may be a leak. So, I poked around some more in DeJa and found Van Flander defending his point over the last week in news = sci.astro, "Speed of Gravity?" thread. Still working on understanding what he's saying. Probably hopless (for me) or in there with the wavicle.

[JoeyBlades]

Einstein wrong? Sure, about many things... did someone say "Cosmological Constant"? Also, have you ever read any of his books? He constantly uses the word 'relatively' when he means 'relative'... There are some other grammatical faux pas, as well... But to say the Theory of Relativity is wrong is a bit extreme; it's probably better to say that it's just incomplete. But then I'm betting $100 that whatever theory finally replaces/supplements it will also be deemed to be incomplete within a coupl'a hundred years, as well... Science is a moving target.

As to time dialation, I think Brian Green had the best intuitive proof that it must occur, that I've seen. To believe the proof, you must accept that the speed of light is a constant in whatever medium you choose. Now imagine a clock that is constructed of two perfectly reflecting, opposing mirrors, oriented horizontally and in parallel. Let's get a photon bouncing between these mirrors in a perfectly vertical way (i.e. there's no Y component to it's vector). Since the photon travels at a constant speed, the time from bottom mirror to top mirror and back to bottom mirror is constant. Let's call that one tick. Now let's introduce a couple of observers. One of them is standing on the bottom mirror (hey, it's a big mirror). The other one is standing at some fixed point that I'm going to call the origin. Both observers perceive one tick to be the same. Now let's set the mirror array, with our first observer in motion. At first the speed is fairly slow and both observers perception of one tick still looks pretty much the same. Let's accelerate the mirror array and our first observer so that they are now moving at half the speed of light. The observer standing on the mirror sees what he always saw. The photon bounces exactly the same distance from bottom mirror to top mirror and the photon is still traveling at C, so one tick still equals one tick, right? Well, before we answer that, let's look at the clock from the perspective of the observer at the origin. Now instead of a photon bouncing in a perpendicular line between two mirrors, he sees the photon painting a sawtooth pattern in a plane. The photon now has to cover more distance than before because it has X and Y components in it's vector and the X component hasn't changed. Since the photon still travels at C, one tick is now slower than it used to be from the perspective of the observer at the origin. Ergo, time has dialated for our observer at the mirror array - he just hasn't realized it yet.

Hope this all makes sense and hope I didn't leave anything critical out. I'm recounting Green's example from memory, not verbatim. There are some other subtle points that I've intentionally left out, but I'll wait and see if I draw any fire before I fill in the gaps.

[Avumede]

If there is a speed greater than the speed of light, such as gravity, the theory of relativity would not be overturned. Simply replace the speed of light with the new maximum speed. There can be no such thing as determining synchronicity of events unless there is an infinitly fast "instantaneous" signal speed.

[John W. Kennedy]

Special Relativity is certainly true, at least within the limits that make it "special".

General Relativity is a little more iffy. Something a whole lot like it is certainly true, but there are still details awaiting confirmation, and rival theories that are similar, but not identical. Most people are betting on Einstein, though.

There is a problem, however, in mixing relativity with quantum theory. Somewhere in the middle there's a new theory we don't have yet.

As to the whole speed of light thing -- here's the problem. It is a fact, measured over and over and over again, that no matter how fast you're chasing light, it's always going exactly C faster than you are. That means that if two people are both chasing the same light, but at different speeds, it's going at exactly C faster than both of them.

"But," you say, "that's ridiculous; it can't be going at two speeds at once."

Yup. It's ridiculous. But it's true anyway.

Special Relativity is just the math showing how the universe has to work, given that this totally wacky fact is true.

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John W. Kennedy
"Compact is becoming contract; man only earns and pays."
-- Charles Williams

[Studi]

Heinlein wrote a whole novel around the twin paradox.

Of course, real scientists don't like working with people. The twin paradox can be made non-personal. Think of a worm-hole (just do it) that's is in such a shape that its entrance and exit are maybe 2 metres apart, and facing each other. One mouth (entrace/exit) will be slightly ahead of the other in time. So one mouth may be, say, five seconds ahead of the other (We can now say one has time 0 and one has time +5). If a billiard ball is rolled into into the one with time 0, it will come out the other mouth five seconds later. Say it takes 10 seconds for the ball to role in to the mouth; therefore, the whole process is complete in 15 seconds.

We need to assume that the ball gains velocity while on its 5 second trip through the wormhole. Now, roll a ball into the one that is time +5. The ball will come out of the mouth that is time=0, so it will go back in time five seconds, basically. This means, that there will be two balls (the same ball, two copies) at the same time. This is because the first ball went through in five seconds and then came out in the past; this was only half-way through its original ten second trip into the t=0 mouth.

If the ball is rolled into the t=+5 mouth, and it has the correct direction, and it gains velocity, can't the ball hit itself in the past in such a way that it never enters the t=+5 mouth? This would mean that the ball would never enter the wormhole in the first place, but then how could it hit itself?

Sorry if I messed up, read this in a fascinating Hawking bio.

Studi

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When I grow up, I want to be the Minister of Silly Walks.

[Studi]

Sorry for the double post...

It's not that relativity is wrong...it just doesn't seem to agree with the rest of physics often.

Relativity = the science of the big
Quantum mechanics = the science of the small

However, it seems that relativity and q. mechanics often contradict each other. This is where problems arise.

Studi

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When I grow up, I want to be the Minister of Silly Walks.

[RM Mentock]

Originally posted by <font color=#FF30c0>emarkp</font>:
The text of the article can be found at: http://www.ldolphin.org/vanFlandern/gravityspeed.html

This is Galilean Electrodynamics. The article does appear in Physics Letters A, The speed of gravity (http://www.elsevier.nl/gej-ng/10/36/25/40/19/18/article.pdf) (as well as Comment on "The speed of gravity" (http://www.elsevier.nl/gej-ng/10/36/25/55/28/48/article.pdf) and Reply to comment on: "The speed of gravity" (http://www.elsevier.nl/gej-ng/10/36/25/55/28/49/article.pdf) but the article at the above link includes some text that does not seem to have appeared in the journal version. At least two examples:

An old saying among Air Force bomber pilots: "You get the most flak when you're directly over the target."

And

Self-introduction of a first-timer in the sci.physics.relativity newsgroup: "Let me start out with the standard disclaimer...I am an idiot, I know almost nothing, I haven't taken calculus, I don't work for NASA, and I am one-quarter Bulgarian sheep dog. With that out of the way, I have several stupid questions..." Alex Wagner.

I don't know why.
<font color=#FCFCFC>----------------
rocks</font>

[RM Mentock]

Ah...crap. I forgot to include a space after the URL. Sorry. I hope that is still readable. (Sure would be nice to have a preview feature...I think I'm going to add that to my sig.)

Originally posted by <font color=#FF30c0>KeithB</font>:
However, people have done a lot of good things with the Copenhagen interpretation, which is my test of a good theory. My point was that he used his *intuition* to pronounce judgement on the theory, not facts.

The Copenhagen interpretation is itself mostly intuition. One can go a long ways with intuition, but--as you mention Einstein did--you eventually run into facts. Einstein's intuition has not been completely discounted, but that should be of almost unscientific interest anyway.
<font color=#DCDCDC>----------------
rocks</font>

[Avumede]

About the Van Flandern article...

reading the article, little "kook" buzzers sounded in my head when I saw that he thanked sci.physics, and of course, did not publish in anything that looked respectable to me.

Searching in sci.physics, it became clear everyone there thinks he's a nut. Do a search in deja.com. Basically, his misconception is to believe the "gravity" and "gravity waves" are the same, and they are in fact not. Gravity is what holds you to the ground, but gravity waves are different, and could transmit information.

Flander's seems to play fast and loose with
different theories. When he says a delay in
gravitation would be detected in orbits,
he is using Newtonian equations (old, outdated), not General Relativity equations. In actuality, the force depends on velocity as well as position, and so really the force is not quite central.
(these arguments taken from the link below..)

For more info, check out:
http://www.math.washington.edu/~hillman/PUB/debate

[falcon2]

Just go here for the answers: http://math.ucr.edu/home/baez/physics/relativity.html

Warning! Reading material posted there may cause your brain to turn to pudding and run out of your ears.

[JonF]

an article published at the end of 1998 that suggests rather strongly that Special Relativity is wrong.

There have been lots of suggestions. None have panned out.

Basically, I think this fellow puts forth a pretty good argument. All of the objections I had were neatly addressed in the article.

I've seen that article before. It is indeed well-written and seems plausible. However, IMHO the arguments boil down to arm-waving. I don't know why the editors accepted it for publication. He's trying to analyze using a mixture of Newtonian Mechanics and Special Relativity, and they don't blend.

The sort of discussion that he presents is useful for visualizations and discussions, but for the real answers you gotta do the math.

Briefly, it is not correct to analyze gravitational interactions by Special Relativity with force vectors. In many cases, you can reasonably approximate the interaction by force vectors. When you do, you find that the force vectors do not point in the same direction as the Newtonian force vectors, and it happens that the propagation of gravity at the speed of light and the change in direction of the force vectors exactly cancel. This means that the Newtonian analysis (which does require infinite propagation speed for gravity) gives the correct answers in all but the extreme situations. It does {i]not[/i] mean that gravity actually propagates at a speed faster than "c". See Does Gravity Travel at the Speed of Light? (http://math.ucr.edu/home/baez/physics/grav_speed.html).

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jrf

[JonF]

I may be wrong, but arguing against the Uncertainty Principal is more fundamental than disagreeing with the Copenhagen interpretation

Principle, not principal, but I get the meaning.

The uncertainty principle is not more fundamental than the Copenhagen Interpretation, nor is it a foundation of quantum electrodymics. It is one of the milestones along the path of the development of the theory. However, it is possible to formulate and interpret quantum electrodynamics without any reference to an uncertainty principle. I seem to recall Feynman explaining this in his inimitable fashion, but I can't remember where.

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jrf

[JonF]

However, it seems that relativity and q. mechanics often contradict each other.

Yup. Problem.

But that does not mean that relativity is incorrect. It's just incomplete. Newtonian mechanics is correct ... except in high gravitational fields or when velocities are a significant fraction of the speed of light. Just as relativity replaced Newtonian mechanics, without changing the predictions of Newtonian mechanics in most situations, we hope for a theory that will unify QED and relativity. It's a safe bet that such a theory will make the same predictions as QED and relativity in most circumstances.

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jrf

[JoeyBlades]

John W. Kennedy writes:


That means that if two people are both chasing the same light, but at different speeds, it's going at exactly C faster than both of them.


Misleading, if not incorrect. Light travels at one speed, independent of the speed of the observers. Your statement suggests that the speed of light is sometimes greater than C - i.e. my velocity plus C. It is true that all observers will measure the speed of light to be the same and this seems to be a paradox when you consider that all observers will not agree on the speed of, say a comet racing through the cosmos. However, if you stop thinking of light as a bunch of photon projectiles and think of it as a propagating wave, the paradoxes start to vanish.

[RealityChuck]

I should add that, while Special Relativity is nearly univerally accepted among physicists, there are some questions about General Relativity. So far, every experiment tried to test these possibility upheld General Relativity, but I think we should honor Robert Dicke, who proposed many of these. The poor guy has failed every time, but deserves a lot of credit for trying.

As for Special Relativity, it's easily demonstrated by at least one practical device: the Global Positioning System. This determines position in part by using extremely precise clocks in orbiting satellites, and it was realized that you had to factor in relativistic effects. If relativity were wrong, the GPS wouldn't work.

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"East is east and west is west and if you take cranberries and stew them like applesauce they taste much more like prunes than rhubarb does." -- Marx

Read "Sundials" in the new issue of Aboriginal Science Fiction. www.sff.net/people/rothman (http://www.sff.net/people/rothman)

[RM Mentock]

The links put up by <font color=#FF30c0>emarkp</font> actually make the point that relativity is wrong because GPS works!
<font color=#DCDCDC>----------------
rocks</font>

[KeithB]

Thanks for the short explanation of the Uncertainty principle.

While I do not want to tar everyone with the same brush, it appears that the website that this paper is on is Lambert Dolphin's. He is famous for pushing the idea that the speed of light is decreasing since creation. I do not know why this goes hand in hand, but it seems that young earth creationists want to discredit relativity for some reason. I guess they feel that Newton was more christian or something.

[emarkp]

douglips
How could I forget 60C? I was clueless about C at the time. Thanks for helping me pass the class.

Now, as for:
As for Special Relativity, it's easily demonstrated by at least one practical device: the Global Positioning System. This determines position in part by using extremely precise clocks in orbiting satellites, and it was realized that you had to factor in relativistic effects. If relativity were wrong, the GPS wouldn't work.

As RM Mentock pointed out, the article suggests that this is in fact a big problem. The GPS satellites were set with the assumption that the satellites would be moving at a constant speed at a specific altitude. However, they're moving in an accelerating path around the Earth, and the speed wrt the observer (i.e. you and your GPS equipment) is constantly changing. AFAIK, SR says absolutely nothing about an accelerating frame.

So how can you just pretend that the satellites are moving at a constant speed wrt you?

[yamo]

Speed of light depends on medium. Has been slowed to 35 mph in a bose-einstien condensate. Photons have been transmitted at faster than C. Einstein was wrong. B+ for effort.

[emarkp]

Speed of light depends on medium. Has been slowed to 35 mph in a bose-einstein condensate. Photons have been transmitted at faster than C. Einstein was wrong. B+ for effort.

Have to laugh that Einstein was "proven" wrong by his own theories. No, speed of light in this discussion refers to speed of light in a vacuum.

AFAIK, superluminal velocities (> c) are only possible for quantum distances.

[JonF]

Speed of light depends on medium. Has been slowed to 35 mph in a bose-einstien condensate. Photons have been transmitted at faster than C. Einstein was wrong. B+ for effort.

Einstein was right. D+ for your effort {grin}.

A. It's usual to write "speed of light" when we mean "speed of light in a vacuum" and the context makes it obvious what we mean.

B. As far as we can tell, the speed of light is a constant in any medium. All that light does is travel in vacuum and interact with other "particles". Light [i]appears[/b] to move slower in non-vacuum media because the photons interact with the medium, and are absorbed and new photons are emitted. (And this happens in vacuo, too, but doesn't affect the apparent speed of propagation).

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jrf

[JonF]

AFAIK, superluminal velocities (> c) are only possible for quantum distances

It's true that QED includes a non-zero amplitude for light traveling at superluminal (and subluminal) velocity over really really short eentsy-weentsy distances. I don't know if anyone has ever devised an experiment to prove the existence of such a phenomenon.



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jrf

[HeadlessCow]

Aren't GPS satellites in geosynchronous orbit? If so then the system of you and the GPS satellite are not moving toward or away from each other and thus can be treated as a non accelerating frame, correct?

[ZenBeam]

Aren't GPS satellites in geosynchronous orbit?

Nope.

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It is too clear, and so it is hard to see.

[emarkp]

No, GPS are not in geosynchronous orbit. And motion in a circle or ellipse is accelerating.

[douglips]

Regarding GPS, has anyone done the math to determine how off things would be by SR? Obviously the coarse adjustments were made prior to launch as described in the American Spectator article (http://209.67.208.207/499TAS/bethell.htm) previously linked to by emarkp:Now let's turn back to the Global Positioning System. At high altitude, where the GPS clocks orbit the Earth, it is known that the clocks run roughly 46,000 nanoseconds (one-billionth of a second) a day faster than at ground level, because the gravitational field is thinner 20,000 kilometers above the Earth. The orbiting clocks also pass through that field at a rate of three kilometers per second--their orbital speed. For that reason, they tick 7,000 nanoseconds a day slower than stationary clocks.

From this I gather that the GR correction is about 7 times more significant than the SR correction in the specific case of GPS. Begin hand wave of someone who dropped out of GR class: Since the acceleration is due to gravity and the orbit is nearly circular, the GR correction is constant (end hand wave - someone please correct me.)

The article goes on to describe the problem with SR and GPS:

In (Einstein) theory, however, it was expected that because the orbiting clocks all move rapidly and with varying speeds relative to any ground observer (who may be anywhere on the Earth's surface), and since in Einstein's theory the relevant speed is always speed relative to the observer, it was expected that continuously varying relativistic corrections would have to be made to clock rates.

So, I guess my question is has someone done the math to determine what the corrections should be? My off the top of my head guess is that the variations in orbital speed will cancel out over the long term, i.e. they will not build up. We've already accounted for 7000 ns retardation per second, so if the speed of the satellite varies the retardation from 6900 to 7100 ns over time, but still averages 7000 ns retardation due to SR, you won't see a long-term affect. Or if you do, it will be very small. Is there something about the orbits that would make this argument unsound?

Until I read an article on the above SR calculations, I'm not worried about the long-term affect. Now, what about short-term? It seems to me that you can only see a portion of the satellites in orbit, those directly above you. Those satellites will not be far off of the average velocity, so while you are in contact with them the clocks won't vary by more than a few ns - your GPS receiver will probably not be able to resolve this finely.

Anyone have a reference to SR & GPS calculations?

[emarkp]

John W. Kennedy:
I took a look at the TAS article.... Since it doesn't present any actual math, of course, it can't actually be refuted as it stands. On the other hand, when physics is the name of the game, if you don't do the math, you haven't done anything.

....Journals called "letters" will print anything that's reasonably grammatical and on-topic; that's what they're for. Any loony can send something to a "letters"-type journal in any field, get it printed, and then claim that his theory was printed "in a journal". It's about as meaningful as saying that something is "on the Internet".

Two points:

1) The TAS article was an overview. The article it was based on has the math. Try checking that URL.

2) So nothing useful is on the Internet? Or just because you didn't read the actual article with the math means that it must be dismissed because it was in a "Letters" Journal?

I hear my ad hominem and strawman alarms going off.

[Avumede]

emarkp, I've provided a link to extensive discussions over this with real professors of physics. Please read. Von Flandern (sp?) does not understand General Relativity. He does not realize that General Relativity perfectly predicts the orbits of the planets, for example, and does not need the speed of gravity to exceed c. Instead, he only shows Newtonian physics has to have instaneous gravity, which is correct. However, that theory is old and outdated, and GR predicts things much better without having that assumption. He also does not undestand that GPS's take into account relativistic effects.

My link in my post above easily shows that this guy does not know what he's talking about. Before posting again, I advise you to read it. Failing that, at least do a search on deja.com to read the debate first-hand.

[RealityChuck]

GPS was specifically designed to take into account the effects predicted by relativity. No matter what hocus pocus you do to argue with the reality, if relativity were wrong GPS wouldn't work. The fudge factor introduced would have randomly skewed the calculations.

So at best you can argue is that there is another explantion that creates effects exactly as predicted by special relativity. But if so, it's your job to give that explanation.

[John W. Kennedy]

I took a look at the TAS article. It set off my bullshit detector several times, especially toward the end, where it falls back on sheer hand-waving and ignorance.

Since it doesn't present any actual math, of course, it can't actually be refuted as it stands. On the other hand, when physics is the name of the game, if you don't do the math, you haven't done anything.

Here's one example of bullshit, though. Journals called "letters" will print anything that's reasonably grammatical and on-topic; that's what they're for. Any loony can send something to a "letters"-type journal in any field, get it printed, and then claim that his theory was printed "in a journal". It's about as meaningful as saying that something is "on the Internet".

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John W. Kennedy
"Compact is becoming contract; man only earns and pays."
-- Charles Williams

[ZenBeam]

Douglips had a quote withThe orbiting clocks also pass through that field at a rate of three kilometers per second--their orbital speed. For that reason, they tick 7,000 nanoseconds a day slower than stationary clocks.

For 3 km/s, I get 4.32E-6 seconds per day = 4320 nanosecond/day. 7000 / 4320 = 1.62 = miles/km. I suspect someone dropped a conversion factor somewhere.

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It is too clear, and so it is hard to see.

[RM Mentock]

Physics Letters A (http://www.elsevier.nl/inca/publications/store/5/0/5/7/0/5/) in its
Guide for Authors (http://www.elsevier.nl/inca/publications/store/5/0/5/7/0/5/505705.pub.istaut.shtml#istaut) that "All contributions will be refereed." On the other hand, they say that Physics Letters A is an "outlet for novel and frontier physics."
<font color=#DCDCDC>----------------
&nbsp;&nbsp;rocks&nbsp;&nbsp;&nbsp;&nbsp;</font><font color=#FCFCFC>Sure would be nice to have a preview feature</font>

[douglips]

Until I see the calculations of the SR & GR effects on the GPS satellites and understand the issues of why it should/should not cause irreducible complexity in the computations, I can't really say one way or the other whether GPS works because of SR, or in spite of SR.

My gut reaction is I would have heard more if SR predicted total failure and GPS worked anyway, so my guess would be that it works because of SR. However, I'd still be open to the calculations showing how SR would cause huge problems with GPS.

[John W. Kennedy]

I hear my ad hominem and strawman alarms going off.

<sigh!>

Does ad hominem mean anything at all any more, or is it just a completely meaningless insult?

------------------
John W. Kennedy
"Compact is becoming contract; man only earns and pays."
-- Charles Williams

[emarkp]

John W. Kennedy:

Sure, here's how m-w.com defines ad hominem:

Main Entry: 1ad ho·mi·nem
Pronunciation: (')ad-'hä-m&-"nem, -n&m
Function: adjective
Etymology: New Latin, literally, to the person
Date: 1598
1 : appealing to feelings or prejudices rather than intellect
2 : marked by an attack on an opponent's character rather than by an answer to the contentions made

And here's the quote of yours I was referring to:

Journals called "letters" will print anything that's reasonably grammatical and on-topic; that's what they're for. Any loony can send something to a "letters"-type journal in any field, get it printed, and then claim that his theory was printed "in a journal". It's about as meaningful as saying that something is "on the Internet".

Looks like ad hominem to me. You certainly didn't address the issue.

[Padeye]

Originally posted by douglips:
My gut reaction is I would have heard more if SR predicted total failure and GPS worked anyway, so my guess would be that it works because of SR. However, I'd still be open to the calculations showing how SR would cause huge problems with GPS.

There might have been a bit of misstatement that draws away from the discussion. It would be more accurate to say that GPS would not work correctly if relativistic time dilation was not accounted for and corrected.

[douglips]

There might have been a bit of misstatement that draws away from the discussion. It would be more accurate to say that GPS would not work correctly if relativistic time dilation was not accounted for and corrected.

Right. What I'm referring to is one of the articles linked to above says that according to SR, the corrections are continuously varying and therefore GPS cannot work. The article said that the 'simple' corrections for GR and average velocity SR were used and work fine, but (according to the article) the continuously variable speed of the satellites would introduce intractable complexity in the calculations.

My point is, without seeing the math behind the 'SR says you get intractable complexity' I am willing to buy the argument that 'SR says you do NOT get intractable complexity', because I was able to reason it out in my head on the previous page.

[emarkp]

My thanks to Avumede for posting some good links to discussions that happened in sci.physics and sci.physics.relativity. I'm pretty convinced now that Tom Van Flandern is wrong. He makes some arguments that seem to make sense intuitively, but he doesn't appear to understand the GR model of gravity. I've discarded his article as part of my accepted information.

Now, as for quoting GPS as the ultimate proof RealityChuck, I have stated why I don't buy it. You have ignored that. Believe it or not, simply asserting something over and over again does not make it true.

[John W. Kennedy]

Looks like ad hominem to me.

Then maybe you'd better try thinking harder. Or you could just get a textbook on elementary logic....

The statement, "This argument makes a deceptive appeal to authority by citing a statement made in an open forum as though it were ipso-facto blessed by the community," is no more an ad-hominem argument than, "2 and 2 is 22," is a statement in arithmetic.

And, seeing that it is impossible to refute a statement that has not been coherently made, about all I can say in answer to the vague and unspecific TAS article is that it bears the characteristic attributes of bad science.

------------------
John W. Kennedy
"Compact is becoming contract; man only earns and pays."
-- Charles Williams

[emarkp]

John W. Kennedy:
And, seeing that it is impossible to refute a statement that has not been coherently made, about all I can say in answer to the vague and unspecific TAS article is that it bears the characteristic attributes of bad science.

Ah, I think I see the problem. I thought you were dismissing the actual article that was posted in Physics Letters simply because a "Letters" mag is suspect (hence my charge of ad hominem). Now it appears to me that what you were saying is that the article in TAS made a claim of veracity based simply on the fact that the article was published. Is that in fact what you've been arguing?

My apologies if I misunderstood your argument. However, please look at the actual article that TAS was referring to (I posted the link in my first message). It actually makes data-based claims which should be able to be analyzed directly. Specifically, please read the issues with SR calculations wrt GPS.

please look at the actual article that TAS was referring to (I posted the link in my first message). It actually makes data-based claims which should be able to be analyzed directly

Remember, you asked ... I'll be pretty complete about the beginning of the paper, and just hit the points I find interesting at the end. Since the end is a mixture of the history of relativity and conclusions based on the erroneous beginning of the paper, I think this is reasonable. But you'll have to get down the the end of this post somehow to get my comments on the GPS question. {grin}

As I believe I said in another post, the overall problem with Mr. Van Flanden's post is that he tries to mix Newtonian mechanics and General Relativy and comes up with an inconsistent mish-mosh.

Newtonian mechanics give the correct answers if the gravitational "field" strength is low and we asssume infinite propagation time for gravity. If you try to use Newtonian mechanics with a finite gravitational propagation speed you will get the wrong answers. If you try to use any field-based analysis without verifying that it is a reasonable approximation, you may get the wrong answers.

General relativity gives the correct answers for low and high "field" strengths (although, strictly speaking, GR does not include the concept of a field) using gravitational effects propagating at the speed of light in a vacuum.

Further quotes are from his paper:

The effect of aberration on orbits is not seen ... If gravity were a simple force that propagated outward from the Sun at the speed of light, as radiation pressure does, its mostly radial effect would also have a small transverse component because of the motion of the target ... There can be no doubt from astronomical observations that no such force is acting.

Indeed, there is no doubt that there is no such force. However, he is assuming both a finite propagation velocity for gravity (GR) and a force field directed towards the center of gravity of the body (Newton). Not kosher. If the field strength is low enough to approximate the GR solution by a force field (which it is, for the case of the Earth and the Sun), then the force vector does not point towards the center of gravity by an amount that just cancels the effect of the finite propagation speed. Again, see Does Gravity Travel at the Speed of Light? (http://math.ucr.edu/home/baez/physics/grav_speed.html)

Gravity and light do not act in parallel directions ... the acceleration now is toward the true, instantaneous direction of the Sun now, and is not parallel to the direction of the arriving solar photons now.

Basically the same comment as on the first quote. Yes, the force vector (whether measured or derived from an approximation of the GR solution) points toward the current position of the Sun and does not point toward where the center of gravity of the Sun was when the "gravity left the Sun". This is predicted by the GR solution. It seems weird, but it is because there is no force vector; force vectors are convenient visualizations, and are often close enough to correct as to make no difference, but they are only approximations to the true situation.

The solar eclipse test ... Since the observed times of eclipses of the Sun by the Moon agree with predicted times to within a couple of seconds, we can use the orbits of the Sun and the Moon near times of maximum solar eclipse to compare the time of predicted gravitational maximum with the time of visible maximum eclipse. ... In practice, the maximum gravitational perturbation by the Sun on the orbit of the Moon near eclipses may be taken as the time when the lunar and solar longitudes are equal. ... We find that maximum eclipse occurs roughly 381.9 seconds of time, on average, before the time of gravity maximum.

Sorry, when attempting to analyze on as accurate a level as this, we may not assume that the maximum gravitational perturbation occurs when the longitudes are equal. We have to calculate the GR solution and predict when the maximum gravitational perturbation occurs. I haven't done the calculation, but I strongly suspect that the answer would be that the maximum perturbation is not expected when the longitudes are equal, just as the "force vector' is not centrally directed.

Myth: Gravity from an accelerating source experiences light-time delay ... However, a finite speed of propagation of gravitational force must add angular momentum to orbits.

This is the same argument as the first point to which I responded, dressed up with more mathematics. He is still assuming a central force field (Newtonian) and a finite gravitational propagation speed (relativistic), and getting the wrong answer.

Myth: Gravitational waves contribute to gravitational force ...

This entire section appears to be an introduction to the rest of the paper. It is strange that he never mentions curvature of space-time, or changes in that curvature propagating.

Is gravity caused by a curvature of space and time ... rubber sheet analogy ... The reasoning in the analogy further suggests that target bodies simply respond instantly to the local curvature of the underlying spacetime medium

Yes. But the local curvature changes would change only as fast as a disturbance could propagate (as an elastic wave) along the sheet. In this respect the rubber sheet analogy is pretty good. But not in other respects ...

A target body sitting on the side of an indentation would stay in place, with no tendency to roll downhill, unless there were already a force such as gravity underneath the rubber sheet pulling everything downhill

Yes. This is a failure of the analogy, not a failure of the theory on which the analogy is based. He is trying to analyze based on an analogy, which doesn't work. First you calculate using the real theory, then and only then can you try to create or validate an analogy.

And this failure of the analogy helps us identify the precise problem with the curved space-time description of gravity - the lack of causality. Without consideration of why a target body is induced to accelerate through space, and how quickly it receives updates of information about how to accelerate through space, neither the space-time curvature explanation nor the rubber sheet analogy can help us understand why gravity appears to act so much faster than light.

GR is a model. It includes an explicit speed-of-light-in-vacuum propagation velocity for gravitational effects, so it does say "how quickly it receives updates of information ...". However, it does not include a meta-explanation of why Nature acts as she does. We can certainly calculate using the model without knowing why (although why is certainly an interesting question).

And there is no evidence for gravity propagating faster than the speed of light. The examples presented earlier in the paper are flawed, as I explained above. Since gravity does not appear to act faster than the speed of light, there is no point in asking why it does.

[quote]contrary to what the rubber sheet analogy implies, an orbiting body such as a spacecraft orbiting the Earth is not following the curvatu

[douglips]

Thanks, JonF! That was totally what I needed. I just have one piece of the puzzle left.

Why doesn't the SR correction work the opposite way for the satellite? That is, if we had to advance the clock by 7200 ns/day to make us think the satellite's clock was running at our rate, shouldn't the satellite see earth's clock as running at 14400 ns/day too slow? After six years (see above post) wouldn't the satellite say "You may think our clocks are synchronized, but I think you are 14 milliseconds slow." Does the acceleration of the orbit cancel this out or something?

[JonF]

Why doesn't the SR correction work the opposite way for the satellite?

That one makes my head hurt. I'll have to think about that for a while, and hope somebody else jumps in soon {grin}.

One way of looking at it may be the way suggested in GPS Time in Orbot (http://mathpages.com/rr/s6-04/6-04.htm); since GR includes SR, you don't need to calculate the two effects separately. The overall relativistic difference is that the GPS satellite's proper time ticks about 38,700 ns/day fast relative to a clock on Earth, so they slow the clocks down by that amount. Because things don't depend on your frame of reference, a clock on Earth will tick 38,700 ns/day slow relative to the satellite's frame (even if you calculate in the satellite's frame), and therefore will keep pace with the slowed clock on the satellite (while the satellite's proper time clock pulls steadily ahead). However, I admit that I haven't done the calculations and I can't come up with a better hand-waving argument off the top of my head.

Two comments on my previous post; I referred to Mr. van Flanden as Mr. Flanders. Sorry 'bout that. I just noticed that What the Global Positioning System Tells Us About Relativity (http://www.metaresearch.org/mrb/gps-relativity.htm) is also by Mr. van Flanden!!!! Reconciling the two articles is beyond my abilities ... but I don't agree with his analysis of the twin "paradox".

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jrf

[RM Mentock]

Originally posted by JonF:
Reconciling the two articles is beyond my abilities ... but I don't agree with his analysis of the twin "paradox".

Part of the discrepancy is from where you quoted him as saying "No ... corrections ... were needed." In context, the meaning is a bit different. In his article (http://www.ldolphin.org/vanFlandern/gravityspeed.html) he says:No "relativity of simultaneity" corrections, as required by SR, were needed. This too seemed initially to falsify SR. But on further inspection, continually changing synchronization corrections for each clock exist such that the predictions of SR are fulfilled for any local co-moving frame. To avoid the embarrassment of that complexity, GPS analysis is now done exclusively in the Earth-centered inertial frame (the local gravity field). And the pre-launch adjustment of clock rates to compensate for relativistic effects then hides the fact that all orbiting satellite clocks would be seen to tick slower than ground clocks if not rate-compensated for their orbital motion, and that no reciprocity would exist when satellites view ground clocks.

That's his version. My take on that: it means that any frame of reference is valid in GR, rotating or no. Might as well use the easy one, the Earth-centered inertial frame. If you were to analyze the complex relationships when you slap a co-moving frame on a single GPS satellite--analyzing the rest of the system from that frame--you still get the same answer, it's just more complicated. That sounds a lot like what Einstein was getting at.
<font color=#ECECEC>----------------
&nbsp;&nbsp;rocks</font>

[douglips]

From the Van Flandern article (http://www.ldolphin.org/vanFlandern/gravityspeed.html):
Finally, the Global Positioning System (GPS) showed the remarkable fact that all atomic clocks on board orbiting satellites moving at high speeds in different directions could be simultaneously and continuously synchronized with each other and with all ground clocks. No "relativity of simultaneity" corrections, as required by SR, were needed. This too seemed initially to falsify SR. But on further inspection, continually changing synchronization corrections for each clock exist such that the predictions of SR are fulfilled for any local co-moving frame. To avoid the embarrassment of that complexity, GPS analysis is now done exclusively in the Earth-centered inertial frame (the local gravity field). And the pre-launch adjustment of clock rates to compensate for relativistic effects then hides the fact that all orbiting satellite clocks would be seen to tick slower than ground clocks if not rate-compensated for their orbital motion, and that no reciprocity would exist when satellites view ground clocks.

I guess what he's saying is that if you were on a satellite, SR would dictate that you would see earth clocks moving slower than your clock, but that van Flandern says you would not.

After some searching, I've been unable to find a decent article outlining what the calculations are vs. the observations.

It sounds like van Flandern doesn't believe the two-way street of SR, and believes that if you were on the satellite you'd see earth clocks moving faster than your clock.

This doesn't seem that difficult to verify. If the correction for SR is 4320 ns/day, as calculated by ZenBeam, then if something were in orbit for 2000 days the difference would be about 8 milliseconds, easily measurable. So, after six years or so, either the satellites would report "Hey, your clocks are 8 milliseconds slower than mine" or "Hey, your clocks are still synchronized with mine."

I guess the argument is that since we jacked their clock around so it looks to run at the same rate as ours, they (the satellites) must see our clock running slow, and eventually get out of sync. I think I understand the argument now, but I'm not sure what the appropriate response is in terms of doing calculations to determine what is right and wrong.

I'll need to get a bit more curious before I pull out my SR text and try to figure this out, though, as I still have a job.

[JonF]

Why doesn't the SR correction work the opposite way for the satellite?

OK, I've thought about it some, and I pretty much give up. However, I did find another link with some interesting explanations and simpler math: The Global Positioning System (http://www.phy.syr.edu/courses/PHY312.98Spring/projects/GPS/GPS.html) (warning - lots of typos). In there, they discuss the issue of what goes on in the satellite's frame of reference, by looking at a world-line diagram.

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jrf