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Author Topic: Evidence for large scale length contraction?  (Read 56692 times)

Offline JP

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Re: Evidence for large scale length contraction?
« Reply #200 on: 02/10/2012 00:22:14 »
I've moved this thread to New Theories as it's continued down it's metaphysics path.
 

Offline lightarrow

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Re: Evidence for large scale length contraction?
« Reply #201 on: 02/10/2012 18:17:10 »
If we all agree that the laws of physics (gravity here) form planets as near spherical, by what stretch of imagination is that not reality?
1. Laws of physics say that a planet forms as spherical in their proper frame.
2. Laws of physics say that a planet forms as a deformed sphere in a moving frame.
Did you get it now?
 

Offline old guy

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Re: Evidence for large scale length contraction?
« Reply #202 on: 02/10/2012 20:00:19 »
If we all agree that the laws of physics (gravity here) form planets as near spherical, by what stretch of imagination is that not reality?
1. Laws of physics say that a planet forms as spherical in their proper frame.
2. Laws of physics say that a planet forms as a deformed sphere in a moving frame.
Did you get it now?
Do you understand that the phrases "in their proper frame" and "in a moving frame" define the shapes of planets by how they are observed, denying that they have shapes independent of how variously they are observed?
Do you think that planets change shapes as they are observed differently? What then causes them to change shape with no application of force, or is it the magical power of different observations that alters massive physical objects?

Everyone but extremist SR theorists like yourself understands that planets and stars are in fact nearly spherical, and that their original formation as such does not depend on from what frame of reference they are observed.

Do you understand that "for this observer" vs "for that observer" makes reality observer dependent, as if Earth's shape depended on who is looking at it from what frame?
Do you get that this is idealism? Do you know what that means? Do you think that a falling tree makes no sound unless there is an "observer" present to hear it?
Do you have any idea how absurd that denial of reality is, or is the difference between idealism and realism beyond your comprehension?

Do as yet undiscovered galaxies simply not exist until they are observed?
How far would you like to carry this obvious absurdity. Is an elephant's shape a rope, because a blind man is feeling its tail. How about claiming that a tree trunk shape is equally valid, as "observed" by the blind man holding a leg? "No, an elephant is like a fire hose," says the one holding the trunk. Or does the whole elephant have a shape of its own independent of observation from limited perspective?
Yes, it does, and so does the Earth. Try to get over your idealism-based misconception about that. Science knows Earth's shape, and SR did not reinvent it.
 

Offline lightarrow

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Re: Evidence for large scale length contraction?
« Reply #203 on: 03/10/2012 11:24:26 »
If we all agree that the laws of physics (gravity here) form planets as near spherical, by what stretch of imagination is that not reality?
1. Laws of physics say that a planet forms as spherical in their proper frame.
2. Laws of physics say that a planet forms as a deformed sphere in a moving frame.
Did you get it now?
Do you understand that the phrases "in their proper frame" and "in a moving frame" define the shapes of planets by how they are observed,
You insist on using the term "observed" but it's incorrect.
The right term is "measured".
At high speeds what you would "observe" is different from what you would measure.
Quote
Science knows Earth's shape.
Indeed: science *knows* that Earth's shape is not spherical in a moving frame.
Science doesn't work according to what *you think*, but according to what *everyone measures*.
And this is the last answer of me.
« Last Edit: 03/10/2012 11:29:30 by lightarrow »
 

Offline old guy

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Re: Evidence for large scale length contraction?
« Reply #204 on: 03/10/2012 18:46:34 »
lightarrow,
I don't blame you for quitting, since there are no good answers to the questions/challenges i posed in my last post to you.
You say:
Quote
You insist on using the term "observed" but it's incorrect.
The right term is "measured".
At high speeds what you would "observe" is different from what you would measure.
Your last statement is a false dichotomy.
Most SR advocates use the terms 'observed' and 'measured' interchangeably, as "measured" is just the formal quantification of what is observed; and we all know that a 'frame of reference' can be abstract, not literally requiring a personal observer, as I have said here before.
Quite a lame criticism.
You say:
Quote
Indeed: science *knows* that Earth's shape is not spherical in a moving frame.
Science doesn't work according to what *you think*, but according to what *everyone measures*.

See... Earth is a "real" solid physical planet. It doesn't change shape to accommodate all possible differences in how it might be observed/measured. So observing/measuring it "in a moving frame" does not make it flatten out into a very oblate spheroid, even though it my appear so distorted from a high speed frame. That is the source of your continuing confusion, and that of all SR theorists in this forum who agree with you. You fail to distinguish appearance (the image of the object) from the object itself. The elephant is not, in fact, shaped like a rope.
 

Offline yor_on

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Re: Evidence for large scale length contraction?
« Reply #205 on: 03/10/2012 19:47:03 »
There is one frame from what you say is (approximately) true OG. The local one where you are 'at rest' with what you measure. But then it becomes a philosophical question which frame is 'more true' than another, if you want a indivisible universe? Because then all frames of reference must be as 'true', as they all need to be in-cooperated in this universe.

Just exchange each 'point' in our universe with a 'observer' but keep 'gravity', to see why I state it this way.

Or you can take a stand in where you define the 'truth' of 'reality' as belonging solely to the 'local description', meaning where you are in space and time, as you observe/measure. From a relativistic point of view that is what I see you try for here, but to do so you now will need to define how all those different 'local definitions' can exist, and all be true for those observing? Because you still have this universe consisting of 'observers', although you now made each one a 'creator' of their own unique universe, as all observations still must differ if compared,  if you see my drift there?

What is good with such a reasoning is that it gives us a 'preferred frame of reference' which actually is how it is treated practically as I think, considering the validity and importance we give 'repeatable experiments'. Aways done locally, then tested/compared in equivalent (relativistically seen) frames of reference (measured in uniform motion mostly). '

But it still need to answer how this can be possible? If so?
And that is one tricky subject OG.
=

When it comes to 'simultaneity', in a indivisible universe you must need it, or else assume that 'time and its arrow' must be a illusion. But then you by necessity have to do the same with a LorentzFitzGerald contraction, as I see it, as they are a symmetry. And if you allow contractions to 'exist' then you've failed anyway, no matter what you think of 'time'. But we have 'frames of reference gravitationally, on Earth, with time dilations :) so it exist as we can measure it.

In a 'local' definition of reality a time dilation becomes slightly simpler as I think of it as they all become unique descriptions, describing unique universes, slightly shifted out of place/focus from your neighbors. Then there is only one time keeping, and that is the one decided by your wristwatch. And the same will hold true for contractions, meaning that you can treat your local clock and ruler as approximately 'invariant'. But then the next question becomes, if it is so, what is the scale of a 'frame of reference', is it enough with being 'at rest' with what you measure? And there i think one have to answer, no. 'At rest' can only be seen as a approximation as we have gravity as the metric of space. Superimposing light/radiation though can be seen as being 'at rest'. Though we have 'point particles', the Pauli exclusion principle stops them from superimposing, normally treated at least. Anyway, the one thing joining them (when comparing between different frames of reference) is something we only can measure as having a 'beginning', as in a recoil, and a 'end', as in a annihilation, but doesn't exist in between?


Radiation.
« Last Edit: 03/10/2012 20:29:41 by yor_on »
 

Offline old guy

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Re: Evidence for large scale length contraction?
« Reply #206 on: 03/10/2012 22:01:06 »
yor_on:
Quote
There is one frame from what you say is (approximately) true OG. The local one where you are 'at rest' with what you measure. But then it becomes a philosophical question which frame is 'more true' than another, if you want a indivisible universe? Because then all frames of reference must be as 'true', as they all need to be in-cooperated in this universe.

The universe is filled with bodies which were formed by various laws. Gravity is the one which makes stars and planets form as nearly spherical. There is no philosophy involved in that. It is the physics of how cosmic dust and debris is formed into planets and stars.
Enter length contraction theory: "For a frame of reference" flying by at near 'c', such objects may appear very oblate, nothing close to spherical.
That does not change the law of physics (gravity) that made them spherical in the first place.
If you are a scientist of the future charged with measuring and describing planets and stars in far away solar systems, flying there at near 'c', what will be your report?... that they are all extremely flattened, or that they are pretty much like our local system?
I would suggest that you slow down and then "park" in the orbit of all objects to be measured to get the most accurate measure. But if that is inconvenient and an inefficient use of rocket power, you could always apply the Lorentz formula to account for your velocity as a factor distorting the images of the bodies your are zipping past. But in no case will you be telling "mission control" that all those bodies are somehow strangely "pancaked" in shape.
Is that clear enough?
(Out of time... More later as "it permits.")
 

Offline old guy

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Re: Evidence for large scale length contraction?
« Reply #207 on: 04/10/2012 00:14:13 »
Just another piece added to last post.
yor-on:
Quote
Because you still have this universe consisting of 'observers', although you now made each one a 'creator' of their own unique universe, as all observations still must differ if compared,  if you see my drift there?

SR theory made each "observer" a "creator" of each frame-specific version of each resulting, as measured, unique universe.
My argument is exactly the opposite.... that the universe and all its objects are "as they were formed by the laws of physics," totally independent of differences in observation. Why is this concept so hard to communicate clearly?
 

Offline yor_on

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Re: Evidence for large scale length contraction?
« Reply #208 on: 04/10/2012 13:39:02 »
It's not hard to communicate OG. It's just that you have to refute relativity, both versions I presented, to make that statement true. And if you can't do that then is will be a dreamers position, what should have been, but what isn't.
 

Offline old guy

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Re: Evidence for large scale length contraction?
« Reply #209 on: 04/10/2012 18:37:44 »
It's not hard to communicate OG. It's just that you have to refute relativity, both versions I presented, to make that statement true. And if you can't do that then is will be a dreamers position, what should have been, but what isn't.
So.... Nothing specifically in reply to my last two posts?

I'll walk you through the last point where you had my position exactly opposite.
(The reason I commented on the lack of communication.)
You:
Quote
    Because you still have this universe consisting of 'observers', although you now made each one a 'creator' of their own unique universe, as all observations still must differ if compared,  if you see my drift there?
Me:
Quote
SR theory made each "observer" a "creator" of each frame-specific version of each resulting, as measured, unique universe.
My argument is exactly the opposite.... that the universe and all its objects are "as they were formed by the laws of physics," totally independent of differences in observation.

SR, not I, makes each observer "a creator of their own unique universe." "For observer A" Earth is nearly spherical, while "for observer B" Earth is nearly flattened. Is there a "real Earth" with an intrinsic shape of its own, as originally formed by gravity, or does each different observer (frame of reference) create his/its own unique version of Earth?
Do you understand "my drift" now? Are you willing to answer honestly?

Do you disagree with this, from 206:...
Quote
The universe is filled with bodies which were formed by various laws. Gravity is the one which makes stars and planets form as nearly spherical. There is no philosophy involved in that. It is the physics of how cosmic dust and debris (ed: and gasses) (are) formed into planets and stars.

Enter length contraction theory: "For a frame of reference" flying by at near 'c', such objects may appear very oblate, nothing close to spherical.
That does not change the law of physics (gravity) that made them spherical in the first place.
...If so, how, specifically?

Ps; as I said to lightarrow above:
Quote
Earth is a "real" solid physical planet. It doesn't change shape to accommodate all possible differences in how it might be observed/measured. So observing/measuring it "in a moving frame" does not make it flatten out into a very oblate spheroid, even though it my appear so distorted from a high speed frame. That is the source of your continuing confusion, and that of all SR theorists in this forum who agree with you. You fail to distinguish appearance (the image of the object) from the object itself. The elephant is not, in fact, shaped like a rope.
... nor Earth like a pancake.
« Last Edit: 04/10/2012 18:58:49 by old guy »
 

Offline old guy

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Re: Evidence for large scale length contraction?
« Reply #210 on: 04/10/2012 21:42:11 »
Just a piece at the core of the argument, from yor_on in post 4:

"So to invalidate it (edit: length contraction) one will have to redefine 'c' as a variable instead of a constant.

So are we then left with an impossible choice: To redefine 'c' as a variable or to redefine Earth's diameter as a variable?
How could the latter vary, given that Earth is in fact a solid, immutable (but for trivially) object?

This challenge has consistently been ignored and then the whole thread was moved to where the question will not be noticed.

Maybe the answer is in the difference between the image of an object, obviously conveyed by light, and the solid ("immutable") object itself. (The image could be distorted while the object stays the same.)

We can probably agree that the Earth's diameter does not physically change to 1000 miles under any circumstance... which makes it a serious question of "what changes?"
If this question is allowed in the Physics section, I will start a thread there on the question of what is variable in this case. If the question is still forbidden, this is not science. Please advise.

I am asking you, JP, to allow me to move this question back to the physics section for serious debate by physicists.
Suggested title:
"Does invariant 'c' require a variable Earth diameter?"

 
 

Offline JP

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Re: Evidence for large scale length contraction?
« Reply #211 on: 04/10/2012 22:40:49 »
Yes, you can start a new thread.

If you use it to evangelize (push the same arguments you've been making and are making in this post that the earth must "really" be invariant), then given the number of warnings you've gotten, you may face a temporary or permanent ban.
 

Offline yor_on

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Re: Evidence for large scale length contraction?
« Reply #212 on: 04/10/2012 22:43:53 »
Ahh JP. i have a suspicion it is this thread OG was referring to, which I just finished, and planning to answer, finding your new reply as I was going to post.

"No OG, this is philosophy, maybe 'philosophy of relativity' but nowhere near science. If you could suggest a experiment in where it could be proved that a length contraction doesn't exist, as defined relative some other frame of reference, then is would close in on science though.

Can you do that?"
 

Offline old guy

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Re: Evidence for large scale length contraction?
« Reply #213 on: 05/10/2012 18:36:11 »
Yes, you can start a new thread.

If you use it to evangelize (push the same arguments you've been making and are making in this post that the earth must "really" be invariant), then given the number of warnings you've gotten, you may face a temporary or permanent ban.
This sounds like, if I started a new thread on the very specific question, "Does invariant 'c' require a variable Earth diameter?", it  would automatically be locked and I would be banned. ... but, "Yes, you can." Thanks.

I would (still) settle for a straight answer right here in this thread to these questions, as above:
Quote
So are we then left with an impossible choice: To redefine 'c' as a variable or to redefine Earth's diameter as a variable?
How could the latter vary, given that Earth is in fact a solid, immutable (but for trivially) object?
This challenge has consistently been ignored. "For this frame" vs "for that frame" does not answer it. It only addresses how it might me observed and measured variously... which is not the question.
Science must not cop out and claim that what we know about Earth (its precise shape) varies with how we look at it. Physics tells us that a change in shape would require application of force, and length contraction theory does not claim to apply any forces.

If only these challenges were directly addressed, no new thread would be needed.

Same for my “suggested title” for a new thread in the Physics section.

So, JP, does Earth’s diameter as a solid object vary with how it is measured or not? If you insist that it  would BE contracted if measured from a very high speed frame, how can physics account for such a shrinkage in a solid, rigid planet? This remains a very sincere and reasonable question requiring an explanation from physics besides “It would appear flattened from  the extreme frame.” (No doubt it would.)

Also, my "probe," measured to be 10 meters long from Earth as it approached at .866 c,(edit) would not fit into a 10 meter shuttle bay sent to retrieve it. Its "contacted length" was 10 meters, but its actual length (what better adjective, I do not know) was 20 meters.
Why is this NOT a conclusive example proving my point? Traveling at .866 c (edit) did not change its length but only its apparent length. How is this wrong?
Ps; yor_on:
Quote
If you could suggest a experiment in where it could be proved that a length contraction doesn't exist, as defined relative some other frame of reference, then is would close in on science though.

Can you do that?

My above thought experiment did just that. Since we can not travel at relativistic speeds... upon which "length contraction" depends,... such experimental "proof" (evidence, anyway) must depend on thought experiments, as do most "examples" of large scale length contraction from its advocates. Both "sides" are allowed such thought experiments. There is no way a 20 meter probe will fit in a 10 meter bay. What more proof could you ask for?
« Last Edit: 06/10/2012 18:57:51 by old guy »
 

Offline old guy

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Re: Evidence for large scale length contraction?
« Reply #214 on: 06/10/2012 19:02:21 »
Does invariant 'c' require a variable Earth diameter?
If so, how does physics explain the latter... or would it simply appear to vary from and extreme frame?
 

Offline wolfekeeper

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Re: Evidence for large scale length contraction?
« Reply #215 on: 07/10/2012 00:12:29 »
There is no way a 20 meter probe will fit in a 10 meter bay. What more proof could you ask for?
Yes it will... and no it won't!

(Surprisingly, both are true!):

http://en.wikipedia.org/wiki/Ladder_paradox
 

Offline butchmurray

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Re: Evidence for large scale length contraction?
« Reply #216 on: 07/10/2012 03:36:56 »
If the probe fits in the bay when they are both at relative rest, the probe will always fit in the bay.

The reason is that there better not be a relativistic difference in velocity – which would cause appreciable length contraction - as the probe enters the bay.

So with the relative velocities of the bay and probe near zero, there is no length contraction to consider.
 

Offline old guy

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Re: Evidence for large scale length contraction?
« Reply #217 on: 08/10/2012 21:59:07 »
There is no way a 20 meter probe will fit in a 10 meter bay. What more proof could you ask for?
Yes it will... and no it won't!

(Surprisingly, both are true!):

http://en.wikipedia.org/wiki/Ladder_paradox
You can not have it both ways. That is why I set it up as I did.
The probe *appeared to be* 10 meters long from Earth. Since it was approaching Earth at .866c, it was *measured to be* 10 meters, "length contracted" by 1/2 at that velocity. Of course, to retrieve any object in space, the shuttle must match velocities with the object... come alongside. Then the *actual length* of the probe was found to be 20 meters. So it simply will not fit. I have repeated this at least a dozen times. Do you get it yet?

Butchmurray:
Quote
If the probe fits in the bay when they are both at relative rest, the probe will always fit in the bay.
See above. It was measured to be 10 meters at a velocity relative to Earth which made it appear contracted to 10 meters. The "proof" that it would not fit is found when the shuttle enters the same frame as the probe. "Ooopse!" It is actually 20 meters long!

Quote
The reason is that there better not be a relativistic difference in velocity – which would cause appreciable length contraction - as the probe enters the bay.
It is as given for any retrieval project that the object and the retrieval craft must be traveling at the same velocity. I've repeated that at least a dozen times.

Quote
So with the relative velocities of the bay and probe near zero, there is no length contraction to consider.

Right, but the question was, will it fit in our 10 meter bay? We better know the answer before we send out our shuttle to capture it. (No.)

The same holds true for Earth's diameter as measured from a fast fly-by.
Here is a quick review of that argument from two recent posts:   

Quote
    So are we then left with an impossible choice: To redefine 'c' as a variable or to redefine Earth's diameter as a variable?
    How could the latter vary, given that Earth is in fact a solid, immutable (but for trivially) object?

This challenge has consistently been ignored. "For this frame" vs "for that frame" does not answer it. It only addresses how it might me observed and measured variously... which is not the question.
Science must not cop out and claim that what we know about Earth (its precise shape) varies with how we look at it. Physics tells us that a change in shape would require application of force, and length contraction theory does not claim to apply any forces.
Also:
If you insist that it  would BE contracted if measured from a very high speed frame, how can physics account for such a shrinkage in a solid, rigid planet? This remains a very sincere and reasonable question requiring an explanation from physics besides “It would appear flattened from  the extreme frame.” (No doubt it would.)
Or in 214; here it is in a nutshell, but none of the length contraction experts here dare address the challenge:
[quote]Does invariant 'c' require a variable Earth diameter?
If so, how does physics explain the latter... or would it simply appear to vary from an extreme frame? [/quote]

 

Offline butchmurray

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Re: Evidence for large scale length contraction?
« Reply #218 on: 09/10/2012 05:53:18 »
Quote
Quote
So with the relative velocities of the bay and probe near zero, there is no length contraction to consider.

Right, but the question was, will it fit in our 10 meter bay? We better know the answer before we send out our shuttle to capture it. (No.)


Absolutely!

Exercise due diligence. You know its relative velocity. You know its measurements judged from your frame. Crunch the numbers. You will know if it will fit or not. NO PROBLEM.
 

Offline old guy

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Re: Evidence for large scale length contraction?
« Reply #219 on: 09/10/2012 18:27:30 »
Quote
Quote
So with the relative velocities of the bay and probe near zero, there is no length contraction to consider.

Right, but the question was, will it fit in our 10 meter bay? We better know the answer before we send out our shuttle to capture it. (No.)


Absolutely!

Exercise due diligence. You know its relative velocity. You know its measurements judged from your frame. Crunch the numbers. You will know if it will fit or not. NO PROBLEM.
"Absolutely!", what? The example clearly shows the difference between the probe's "contracted length" as measured from Earth and its *actual length* as measured from traveling right beside it, as required to retrieve it. Its velocity relative to Earth is .866 c. That makes it *appear to be* 10 meters long. My point, over and over, is that its *apparent, "contracted" length* is only half of its *actual length*, and the proof of this difference is that it is twice as long as our cargo bay.
It was not "really, actually" 10 meters after all but 20. No way! The proof that its "contracted length" is half of its "actual length."

The length contraction "experts" here refuse to acknowledge that "length contraction" is only an "appearance" due to observing it approaching at high speed, whereas is "actual length" remains twice as long.
OK?
What is your answer to the question no one here will touch (for good reason... to avoid making an absolutely absurd claim):
Quote
Does invariant 'c' require a variable Earth diameter?
(Edit: The claim is that " because 'c' is invariant, length is not invariant.")
If so, (ed: if Earth's diameter changes) how does physics explain the latter... or would it simply appear to vary from an extreme frame?
My answer: Yes, it would only appear contracted from the extreme frame. Earth does not change diameters, "actually."
 

Offline butchmurray

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Re: Evidence for large scale length contraction?
« Reply #220 on: 11/10/2012 13:43:14 »
Quote
You can not have it both ways. That is why I set it up as I did.
The probe *appeared to be* 10 meters long from Earth. Since it was approaching Earth at .866c, it was *measured to be* 10 meters, "length contracted" by 1/2 at that velocity. Of course, to retrieve any object in space, the shuttle must match velocities with the object... come alongside. Then the *actual length* of the probe was found to be 20 meters. So it simply will not fit. I have repeated this at least a dozen times. Do you get it yet?

I think I understand now.

The shuttle bay can accommodate a 10m probe.

The relative velocity of the probe is .866c.

At relative velocity .866c, the probe is 10m judged from relative rest.

If you know the relative velocity is .866c and you know the length is 10m judged from relative rest, then you know the “at rest” or “proper” length is 20m. You also know the probe will not fit in the 10m cargo bay of the shuttle because when the shuttle’s relative velocity is also .866c the cargo bay will only accommodate a 5m probe judged from relative rest.

In other words your measurements for BOTH the probe and the shuttle bay must be either “rest” length OR contracted length because they will be in the same frame (the same relative velocity or difference in velocity close to zero) as the probe is recovered.
 

Offline old guy

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Re: Evidence for large scale length contraction?
« Reply #221 on: 11/10/2012 18:24:34 »
butchmurray,
Finally... someone 'gets it!' Thank you for paying attention to the example *as I presented it.*
If length contraction advocates did not insist that "proper" length and "contracted" length were equally valid (all frames being equal) the whole example would be very simple.

We recognize the difference between "contracted length" as mere appearance due to observing something traveling at high velocity relative to the observer and  the *actual length* of something as it was either naturally formed (Earth's diameter does not change) or, in this case, built... its "proper length" as measured in its own frame.

So we see a probe approaching Earth at .866c, plug in the formula, and know immediately that it is *actually* 20 meters long. We will not send out a 10 meter cargo bay to retrieve it, because it is not *really* 10 meters long.

It is really very simple when the dogma of "all frames are equal" is removed.

Just one clarification... you said:
Quote
You also know the probe will not fit in the 10m cargo bay of the shuttle because when the shuttle’s relative velocity is also .866c the cargo bay will only accommodate a 5m probe judged from relative rest.

As seen from Earth, the shuttle, now traveling with the probe, will *appear to have* a bay 5 meters long, "contracted" to half its actual length, as the probe also appears. The shuttle bay did not shrink. It was 10 meters on Earth and remains 10 meters as it approaches with the probe. Just because it now "looks" 5 meters long from Earth did not make it shrink to half its length.
This is an extremely persistent misconception among those advocating length contraction.
 

Offline butchmurray

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Re: Evidence for large scale length contraction?
« Reply #222 on: 11/10/2012 20:18:01 »
I truly understand your misgivings about “is” and “appears to be”.

The way I reconciled it was, “It ‘is’ when judged from relative rest”.

Here is something else to ponder:

Suppose inside of the probe there is a constant light projected from one end to the other end of the probe in the direction of motion. What is the difference in that light when judged from the shuttle, which is moving at the same relative velocity as the probe (.866c) and when judged from relative rest?
 

Offline old guy

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Re: Evidence for large scale length contraction?
« Reply #223 on: 11/10/2012 21:46:48 »
butchmurray:
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I truly understand your misgivings about “is” and “appears to be”.

I think it would bring much needed clarity to the SR conversation if everyone understood the difference and did not insist that Is = Appears to Be.
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The way I reconciled it was, “It ‘is’ when judged from relative rest”.

I agree. Scientists must "put it under a microscope" or at least be at rest (same frame) with 'it' to study and measure 'it' accurately.

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Here is something else to ponder:

Suppose inside of the probe there is a constant light projected from one end to the other end of the probe in the direction of motion. What is the difference in that light when judged from the shuttle, which is moving at the same relative velocity as the probe (.866c) and when judged from relative rest?

Yes, I've pondered that a lot over the years.
Seems as if it makes no difference whether the light source or the observer(s) or whatever frames of reference are moving or how fast. They all observe light to travel at the constant speed 'c.' I can't argue with that. The experiments are very conclusive.

My concern is that what is "observed" is an image reflected or projected from an object or light source, not the object itself. So there could be an appearance of contraction due to the medium of light itself as carrier of the image. I don't pretend to know the specifics of how that all that might work. I just know that the image is not the object, and light carries the image.

Btw, thanks for understanding my "probe" example.
 

Offline old guy

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Re: Evidence for large scale length contraction?
« Reply #224 on: 13/10/2012 18:46:54 »
Regarding this from yesterday: "I just know that the image is not the object"...
I also know that a possible image of a flattened Earth (say with a 1000 mile diameter in the direction of an observer's very high speed travel) would/could only be an appearence, an image of a flattened Earth. We all know that Earth's diameter is not, has never been and will never be 1000 miles.

I can not get the "SR experts" here to address this challenge. Since you, butchmurray, win the prize for understanding my probe illustration of "actual vs apparent" length, maybe you would give the shrunken Earth diameter challenge a shot too.

Ps; btw, we are now even on number of posts at 112. Here is your chance to move ahead!
« Last Edit: 13/10/2012 18:52:14 by old guy »
 

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Re: Evidence for large scale length contraction?
« Reply #224 on: 13/10/2012 18:46:54 »

 

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