Fibre-linked atomic clocks put special relativity to the test

@layman,

Nobody? OK, I'll respond to my own question (with another question):

The "problem" (such as it is) begins with the ASSUMPTIONS which SR imputes to (and indeed FORCES UPON), our traveller.

As soon as he becomes inertial (not accelerating), he MUST assume that he is absolutely motionless. He must assume that the earth is moving away from him, and the distant star that is his destination is moving toward him, all while he remains absolutely motionless.

No semi-intelligent astronaut would EVER make this assumption in real life, but let's just suppose the guy is actually that ignorant. So, now what? What's the problem? Where's the "paradox?"

1 Reply

@layman,

Let's take it one more step:

SR (actually the Lorentz transform) says that the "moving" clock will run slower. Since our astronaut thinks he is motionless, and that the earth is the object which is moving, he will conclude that the earth's clock has slowed down, and not his.

Is there a "paradox" now? No, not at all. No paradox is created just because some guy has made a mistake. None is created by the fact that he reached an erroneous conclusion because he based it on a false premse. He's just wrong, that's all. No "paradox" about it.

So where does the "paradox" come in?

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@layman,

I have seen a good number of people claim that there is now a paradox, because each guy now thinks the other's clock is the one which has slowed down.

Such people are wrong. That is not "the" paradox. It's not even a paradox at all. When two people disagree, they have different opinions, that's all. No "paradox" emerges from mere disagreement.

So where does the "paradox" come from? It aint that, so what is it?

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@layman,

You don't understand the fundamental point that the word 'paradox' is used with repect to the common sense concept of the 'equivalence of twins'. However the experiences of the twins is not equivalent since one experiences the forces of acceleration and the other does not. Unless they actually physically meet (occupy the same agreed space time coordinates) after the experiment for age comparison purposes, the experiment is meaningless because it is just dealing with projected thoughts about 'appearances'.
Your rubbish about 'solipsism' is merely a display of ignorance about the contextual relativity of semantics. Whether we have access to an 'independent reality' or not (as Kant advocated), the prevalent view of language is that words do not so much mirror 'reality' as help construct it. And since language is used in communicative contexts involving mutual needs, the final arbiter of meaning IS 'agreement'. The very existence of language is the antithesis of 'solipsism'.

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@fresco,

Whatever, Fresky. You invariably try to turn every thread you enter into one about "language." Start a thread on it, why doncha?

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@layman,

Since all THREADS involve linguistic dancing, your response is ultimately trivial and irrelevant.
If you have any published research in physics I would be pleased to read it, otherwise your persistent running to your hidy hole of your simplistic 'Fresky' caricature' merely undeescores your weakness.

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@fresco,

Fresky, you are, and alway have been, a petty, pompous, and pretentious poseur with an inferiority complex a mile wide. Take it elsewhere, cheese-eater.

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@layman,

Well done ...an excellent example of abuse being the language of the inarticulate .
(I'll take that as a 'no' then on your research publications).

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@layman,

Where was I, Dale? Oh, yeah...

layman wrote:

I have seen a good number of people claim that there is now a paradox, because each guy now thinks the other's clock is the one which has slowed down. Such people are wrong. So where does the "paradox" come from? It aint that, so what is it?

There's nothing paradoxical in the "facts." It comes from the (SR) theory.

The "paradox" only comes in when we are told, by SR advocates, that the travelling twin is "right" in his beliefs, and are then told that the earth twin is "also right."

This creates an insoluble logical "paradox" right off the bat. Both twins agree that they are moving away from each; each claims that HE is motionless; and yet "both are right?" Logically impossible.

But, even putting logic aside, the problem is that, according to SR itself, both are NOT right. When the twins reunite, they are not the same age, nor is each younger than the other (obviously, but that's what we should expect if they are both right).

Instead we are told that the "travelling twin" will IN FACT be younger (which proves he was the one "moving," not the earth twin). He was not "right," after all, SR ends up saying. So SR contradicts both logic and it's own theory by the contradictory claims being made.

Now THAT'S a "paradox." But ONLY if you accept all those claims as true and compelling.

Don't do it, Dale. You'll forever be "puzzled" if you try to make digestible sense of all that.

As you stated, by it's resolution (one IS younger), SR has been forced to treat the earth twin's frame as a "preferred" frame. This really means that SR rejects "itself," so why should YOU accept it, eh?

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Getting back to the article which is the subject of this thread for a minute....

It's already been noted that SR was NOT used to conduct this experiment. Why not? Well, for one thing, SR says that any time dilation between two "objects" depends only on their motion relative to each other. But two separate locations on earth, such as Paris and London, never move "relative to each other." So, using SR, you would never predict any time dilation as between the two. And yet it occurs. So how do they measure that (what theory, and what methods)?

As stated, they use a theory of relative motion which incorporates a presumption of absolute simultaneity (not the bogus "relative simultaneity" espoused by SR) and which uses a preferred frame of reference as the measurement standard. Here the preferred frame used was "the center of the earth." All motion (speed) was calculated with reference to that "preferred" frame, not as between the cities involved:

Quote:

The measurement involved optical lattice clocks in Paris,... and the National Physical Laboratory (NPL) near London. As the Earth rotates, different points on its surface have different velocities relative to the centre of the Earth. Points at different longitudes, for example, move in different directions, while points at different latitudes move at different speeds. As a result, sending signals between atomic clocks at two different points on Earth could reveal RMS violation.

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As the Earth rotates, different points on its surface have different velocities relative to the centre of the Earth. Points at different longitudes, for example, move in different directions, while points at different latitudes move at different speeds.

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@centrox,

Exactly. I just quoted that same passage (and more).

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@layman,

Quote:

SR says that any time dilation between two "objects" depends only on their motion relative to each other. But two separate locations on earth, such as Paris and London, never move "relative to each other." So, using SR, you would never predict any time dilation as between the two. And yet it occurs.

So, bottom line here, this experiment does not "confirm" the predictions of SR. It does the OPPOSITE. It demonstrates that the premises of SR are, as an empirical matter, erroneous.

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@centrox,

Layman is mistaken about geographical locations since although their spatial co-ordinates may be deemed constant , their space-TIME coordinates are not.

Quote:

Curvature of spacetime is a relativistic manifestation of the existence of mass. Such curvature is extremely weak and difficult to measure. For this reason, curvature was not discovered until after it was predicted by Einstein's theory of general relativity. Extremely precise atomic clocks on the surface of the Earth, for example, are found to measure less time (run slower) when compared to similar clocks in space. This difference in elapsed time is a form of curvature called gravitational time dilation.

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@centrox,

....In short, different geographical locations experience differential acceleration (like the twins).

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@layman,

Quote:

Is there a "paradox" here? .....Anybody?

Lay I dunno. It's that 'preferred frame' that bothers me. So yes, anybody....

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@layman,

Quote:

Don't do it, Dale. You'll forever be "puzzled"

Thanks Lay and indeed I am. For instance what happens if I take off near c, travel in a 'straight' line clear 'round the Universe. I am led to believe that when we meet again you'll be older than me, suggesting that my clock really did run slower. However, I wonder if you might assume I'm wrong, that it didn't really

So I'm left with the obvious q: Will I or won't I. Also, let's suppose our part of the Universe is presently in motion, near c. Then when I take off, I'm really coming to a stop. What then

Quote:

they use a theory of relative motion which incorporates a presumption of absolute simultaneity

That's where my RR shines, sdays that light speed can be considered relative too

I know you don't like that term, 'considered,' but it's used by the experts too. They say that after I take off I can then 'consider' myself at rest, which raises all sortsa probs

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@dalehileman,

dalehileman wrote:

let's suppose our part of the Universe is presently in motion, near c.

Relative to what?

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@centrox,

centrox wrote:

dalehileman wrote:
let's suppose our part of the Universe is presently in motion, near c.

Relative to what?

Presumably the CMB, which nobel prize winning (awarded for his work in investigating the CMB) physicist, Dr. George Smoot, has called the "cosmic rest frame."

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@centrox,

dalehileman wrote:
let's suppose our part of the Universe is presently in motion, near c.

Quote:

Relative to what?

To the rest of the Universe

1 Reply

Fibre-linked atomic clocks put special relativity to the test

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