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The Twin Paradox Made Simple

Special Relativity Twin Paradox

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#18 A-wal

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Posted 15 April 2018 - 05:12 PM

Stop muti-posting! Please edit post 12 to include the ones after it and delete the others.
 

A-wal said:  "The astronauts didn't leave their bodies so they themselves didn't go anywhere, from their perspective Earth moved away from and the moon moved towards them. Of course they accelerated to leave the Earth and the had to overpower the gravitational acceleration of the planet to do that but during the journey when they weren't accelerating, the moon was moving towards them every bit as much as they were moving towards it because there's no distinction between the two."

 

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You seem to find it impossible to distinguish fictitious theoretical mathematical/philosopical claims from practical reality, A-wal.

LOL!

 

You say "from their perspective," but that's absurd.  What you really mean is "from MY perspective, which I impute to them and demand that they adopt and adhere to."

No when I specify a perspective I'm referring to the objective reality of what an observer would experience in that particular frame of reference, regardless of whether or not that observer has the intelligence to understand why they experience what they do.

 

No astronaut who went into outer space EVER, from "their perspective," thought they were motionless while the earth moved away from and the moon moved toward them.  EVER!  They know better, as a practical matter, and would (properly) reject and resist your attempt to impute a different "perspective" to them just so you can claim the math model of SR is true as a matter of empirical fact (which it aint).

Astronauts tend to be well versed in physics so I'm sure they'd be perfectly aware that while they're in inertial motion they are free to view themselves as motionless and other objects as in motion relative to them.

 

They wouldn't deny all other physical principles to maintain this philosophical fiction.  You concede that "of course they accelerated to leave the Earth and the had to overpower the gravitational acceleration of the planet."  And what does Newton's law of inertia (which SR accepts) say about that?  That a body in motion will stay in motion unless acted upon by an external force, right?

 

Yet YOU want to say that the instant they stop accelerating and settle into maintaining a uniform speed, then they INSTANTLY STOP ON A DIME and become motionless.  At that moment THEY are suddenly motionless without any explanation of how that is possible (which it aint).  Normal people don't ignore the known laws of physics like that--at least not to the point of claiming that's what's actually happening as opposed to saying it just a complete, yet presumably useful, theoretical fiction to pretend that it's true.

They would also understand that this in no way violates any other established physical principles. Once an object stops accelerating it's an inertial object and whether or not it's motion is a purely arbitrary choice of coordinate system. Motion only makes sense if it's motion relative to another object and once an object stops accelerating to say it can't be viewed as being at rest makes no sense. From the perspective of an object that was already in the frame of reference that the accelerator ends up in (so at rest relative to the accelerator once they've stop accelerating) the accelerator was in motion before accelerating and then decelerated to become motionless relative to them. There's no distinction between acceleration and deceleration, deceleration is just acceleration viewed from a different perspective.

 

No astronaut has ever taken the "perspective" you impute to them, and none ever will.  You couldn't ever even become an astronaut if you were that oblivious to physics.  Astronauts aint stupid.

If the astronauts on their way to the moon judge their velocity by using the moon's frame of reference so they are in motion then it's a valid way to look at it but no more valid than using any other frame of reference. If you think it is then you need to learn to think better. What would happen if the astronauts thought 'let's not go to the moon, tis a silly place. Let's go to Mars instead.' Now they're heading towards Mars but the moon is at rest and you think that's a preferred frame but if they're heading towards Mars then that would have to be a preferred frame, so their frame of reference would have to depend on their object of destination? Do you see how silly that is?

What if Earth, the moon and Mars were in alignment when they decide to go to Mars instead so they didn't even have to change direction, now their 'absolute motion' through space changes based on their decision about which celestial body they'd like to visit. If you think the sun should be used as a basis for absolute motion then what if they decide to visit another star system (they're in the future now)? At would point during the journey would their absolute motion depend on the destination star?

 

A-wal said:  "This only applies to inertial frames of reference.  The frame of reference of an accelerating observer is outside of the frame work of what this model describes...The speed of light isn't constant in accelerating frames, it's always slower."

 

Exactly, which is just one of many reasons why a theory of relative motion which incorporates absolute simultaneity (such as the RMS model) is vastly superior to SR and is used in the GPS while SR is rejected (because it would give inaccurate and contradictory predictions).

 

With accelerating objects, there is no pretense to "reciprocal time dilation," etc.  It is explicitly acknowledged that the clock of an accelerating object runs slower and that the clocks of (relatively) inertial objects run FASTER, NOT SLOWER.  This is an ABSOLUTE phenomenon, not a relative one, as even all SR adherents admit.

 

An AST (absolute simultaneity theory) makes perfectly accurate predictions for ALL moving objects, not just the that extreme minority of objects (if there really are any at all) that are not accelerating.

There can never be absolute simultaneity. It's very easy to show that events that one observer views as simultaneous can't be simultaneous from the perspective of an observer that's in motion relative to the first observer.

 

A-wal:  "There is an inertial frame everywhere in the universe because motion can't be detected."

 

-----

 

Yes, I agree that SR does make this claim, but it's absolutely absurd, nonetheless.

 

SR merely mimics an AST by postulating a preferred, absolutely motionless, frame for every calculation it makes.  According to SR, the preferred frame is always the one YOU are in (if you are inertial).  Any and every thing in the entire universe which is moving with respect to YOU is moving.  YOU are absolutely motionless.  Every observer is a motionless luminous ether unto himself, per the mandates of SR, and there are an infinite number of motionless frames.   Problem is,  as a practical and possible matter, only one frame can be motionless, never more than one when there is relative motion between them.  As I said, the whole notion is ridiculous.

No that's not what the term preferred means in this context. A preferred frame of reference is one in which the laws are different. No such inertial frame exists. Sr doesn't require that every inertial object is at rest in their own frame, it's an arbitrary choice, any inertial observer is free to use any frame of reference in which they are in motion because all inertial frames are equivalent. What's ridiculous is thinking you know better than a model that you can't even understand.

 

Awal said:  "If one twin were to leave Earth and accelerate just the once so they were moving away at a constant velocity and the other twin left Earth later on to catch up and then accelerate into the frame of reference first twin to leave once the second twin catches up then it would be the second twin that left Earth who would be younger."

 

----

 

Yes, of course.  But this is not caused by a change is some fictitious "frame of reference," which exists only as a mental construct.  It is because the accelerated twin is the one ACTUALLY MOVING and it is the moving clock which ALWAYS runs slow.  For whatever reasons, increased speed actually causes clocks (and all physical precesses) to slow down

 

The circumstances are NOT symmetrical, needless to say.  Relative to each other, one is moving (faster), one is not.

You've completely misunderstood, just as you've misunderstood everything else. These are your failures to understand a logically consistent and verified model of reality, not failures of the model. Frames of reference are certainly not mental constructs and neither twin is 'actually moving', they are in motion relative to each other and to say one is moving and one isn't or one is moving faster than the other doesn't make any kind of sense, all inertial motion is relative. It may be nicer for you to think you are capable of understanding this that you can't make sense of the model because the model itself doesn't make sense but I assure you this isn't the case.

 

A-wal said:  "Completely wrong on both counts. All the data empirically proves that the speed of light is constant and therefore that time dilation and length contraction are a fact because it's logically impossible for them not to be."

 

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Wrong.  As I have noted in another thread, the speed of light is NOT constant in every frame, and logically in can't be.

I'm afraid it can, and it has been shown that it is. The fact that you think it's logically inconsistent proves that you simply can't grasp the model because a constant speed of light is definitely not logically inconsistent.

 

It is, however, always MEASURED to be the same.  But that's not because it IS the same.  It's because speed distorts the measuring instruments which are used to calculate and determine the speed of light (time and distance).  That distortion is exactly what the LT "correct for.'

Oh dear, you're having having trouble aren't you. This 'distortion' as you put it is the time dilation and length contraction that allows the speed of light to be measured as the same in all inertial (and entirely equivalent because none are more valid than any other) frame of reference.

 

If it is claimed that one object is "moving faster" than another, then it is legitimate and natural to ask:  "Compared to what?"  AST theories give accurate predictions ONLY when ALL motion is calculated by reference to the center of the dominant gravitational field of the locality where the prediction is made.  As Einstein said: "All physics are local."

 

For calculations involving the speeds of various objects in motion on or near earth, this would be the ECI, as used in the GPS.  For measurements on a solar scale, it is the barycenter, which even the Sun revolves around. Compared to anything else in the solar system, the barycenter is indeed the only point which is not "moving."  Newton, Keppler, Copernicus, et al, used this point to calculate the speed and direction of planetary orbits--using the background of the "fixed stars" as a "close approximation" to another "motionless" frame.

 

For the Milky Way, the black hole at the center of the galaxy's mass is used.  For "universal" measurements, the CMB has been used by astrophysicists as the preferred frame of reference for many decades now.  For practical purposes, all such local frames of reference can be treated as "motionless" for local experiments in order to achieve accurate predictions, even if they are not "truly motionless" in the overall scheme of things..   Reference to the CMB tells us, for example, that the entire MIlky Way is moving at a high rate of speed toward the "great attractor."  But since that motion is common to every object in the Milky Way, it can be ignored when making intra-galactical calculations of relative motion.

 

Of course all such calculations are prohibited by SR, which (purportedly, at least) forbids the use of a preferred frame.  But that does not make their use less accurate--it merely exposes how inaccurate predictions based on the strictly relative motion relied on by SR can be.

The frame in which the CMB is at rest is in no way a preferred frame of reference and nobody but you is claiming that it is. You're free to use any inertial frame in which the CMB is in motion and it changes nothing because all inertial frame are equivalent.

 

Your constant ignorance is very tiresome. You're unable to come up with any kind of coherent argument to support your ridiculous claims, all you can do is demonstrate all the ways in which you're unable to understand the model but guess what, you don't need to understand it. Being understood by people that are incapable of grasping even the basics is not a requirement for an accurate model.



#19 Moronium

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Posted 15 April 2018 - 08:08 PM

A-wal said:  "The frame in which the CMB is at rest is in no way a preferred frame of reference and nobody but you is claiming that it is. You're free to use any inertial frame in which the CMB is in motion and it changes nothing because all inertial frame are equivalent.

 

Your constant ignorance is very tiresome."

 

-------

Yeah, right, eh?    You sound like a broken record which is long on unsupported rank assertion and short on fact, evidence, and argument.  That you are a ardent adherent of solipsism is quite apparent.  I would advise you to wise up if I thought it was possible, blowhard.

 

Here's a little excerpt from Nobel Prize winner George Smoot, made in a report summarizing some of the findings and conclusions of the team of distinguished physicists which he led in connection with the government-funded "U2 anisotropy experiment" for NASA.

 

 

We attribute the dipole anisotropy to the motion of the Earth and Solar System relative to the universal CMB radiation field and thus the distant matter in the Universe. This would seem to violate the postulates of Galilean and Special Relativity but there is a preferred frame in which the expansion of the Universe looks most simple. That frame is the average rest frame of the matter and CMB and from that frame the expansion is essentially isotropic.

 

 

 

http://aether.lbl.gov/www/projects/u2/

 

Of course, you've probably won multiple nobel prizes for physics unlike that loser, Prof. George Smoot, I bet.

 

Here's another "nobody" of the type you referred to, eh?  This quote is from Professor Douglas Scott's FAQ page. He researches CMB and cosmology at the University of British Columbia.

.

 

Q:  How come we can tell what motion we have with respect to the CMB?   Doesn't this mean there's an absolute frame of reference?

 

Scott:  The theory of special relativity is based on the principle that there are no preferred reference frames. In other words, the whole of Einstein's theory rests on the assumption that physics works the same irrespective of what speed and direction you have. So the fact that there is a frame of reference in which there is no motion through the CMB would appear to violate special relativity!

 

However, the crucial assumption of Einstein's theory is not that there are no special frames, but that there are no special frames where the laws of physics are different. There clearly is a frame where the CMB is at rest, and so this is, in some sense, the rest frame of the Universe.

 

 

http://www.astro.ubc.../faq_basic.html

 

You've probably never heard of Lee Smolin, because he's just another "nobody," but here's his take according to a reviewer of one of  his books:

 

Lee Smolin, in his book “Time Reborn”, develops the thesis that “time’ has been gradually removed from physics with the final denouement for “time” being the creation of Special and General Relativity...Smolin goes on to explain why this removal of “time” from physics has been a major obstacle to advancement in certain areas of physics.

 

Smolin concluded that he must give up relative simultaneity and adopt “preferred global time” and a preferred state of rest. He did this because observations of receding galaxies and observations of CBR both indicate there is a preferred rest frame and a preferred global time AND both sets of observations point to one and the same preferred frame.

 

 

 
 
Here's what wiki has to say about this particular nobody:
 
Lee Smolin (/ˈsmlɪn/; born June 6, 1955) is an American theoretical physicist, He received his Ph.D in theoretical physics from Harvard University in 1979.[2] He held postdoctoral research positions at the Institute for Advanced Study in Princeton, New Jersey, the Kavli Institute for Theoretical Physics in Santa Barbara and the University of Chicago, before becoming a faculty member at YaleSyracuse and Pennsylvania State Universities. 
 

He has made contributions to quantum gravity theory, in particular the approach known as loop quantum gravity.  His research interests also include cosmologyelementary particle theory, the foundations of quantum mechanics, and theoretical biology.

 

 

 
He

Edited by Moronium, 15 April 2018 - 10:15 PM.


#20 A-wal

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Posted 16 April 2018 - 01:00 AM

Bigger text size, that helps too add weight to your arguments and improve your credibility. :)

 

 

A-wal said:  "The frame in which the CMB is at rest is in no way a preferred frame of reference and nobody but you is claiming that it is. You're free to use any inertial frame in which the CMB is in motion and it changes nothing because all inertial frame are equivalent.

 

Your constant ignorance is very tiresome."

 

-------

Yeah, right, eh?    You sound like a broken record which is long on unsupported rank assertion and short on fact, evidence, and argument.  That you are a ardent adherent of solipsism is quite apparent.  I would advise you to wise up if I thought it was possible, blowhard.

You haven't been able to make a single argument that isn't easily shown to be a complete misunderstanding of how sr works.

 

We attribute the dipole anisotropy to the motion of the Earth and Solar System relative to the universal CMB radiation field and thus the distant matter in the Universe. This would seem to violate the postulates of Galilean and Special Relativity but there is a preferred frame in which the expansion of the Universe looks most simple. That frame is the average rest frame of the matter and CMB and from that frame the expansion is essentially isotropic.

This is explaining how the CMB frame isn't a preferred frame because it doesn't violate sr. It's only a preferred frame in the sense that's it's the most convenient universe frame to use. A preferred frame in the context of sr is one in which the laws are different, this is just an average motion frame so it's 'preferred' in the common sense of the word but not in the scientific sense.

 

Q:  How come we can tell what motion we have with respect to the CMB?   Doesn't this mean there's an absolute frame of reference?

 

Scott:  The theory of special relativity is based on the principle that there are no preferred reference frames. In other words, the whole of Einstein's theory rests on the assumption that physics works the same irrespective of what speed and direction you have. So the fact that there is a frame of reference in which there is no motion through the CMB would appear to violate special relativity!

 

However, the crucial assumption of Einstein's theory is not that there are no special frames, but that there are no special frames where the laws of physics are different. There clearly is a frame where the CMB is at rest, and so this is, in some sense, the rest frame of the Universe.

This explains why it isn't a violation of sr! "...but that there are no special frames where the laws of physics are different." What the hell is wrong with you?

 

Lee Smolin, in his book “Time Reborn”, develops the thesis that “time’ has been gradually removed from physics with the final denouement for “time” being the creation of Special and General Relativity...Smolin goes on to explain why this removal of “time” from physics has been a major obstacle to advancement in certain areas of physics.

 

Smolin concluded that he must give up relative simultaneity and adopt “preferred global time” and a preferred state of rest. He did this because observations of receding galaxies and observations of CBR both indicate there is a preferred rest frame and a preferred global time AND both sets of observations point to one and the same preferred frame.

I don't know where you got this from but if this dude understood the first thing about this subject he'd realise the CMB is certainly not a preferred frame and the red-shift of galaxies doesn't in any way imply a preferred frame either. Other galaxies are red-shifted from the perspective of every galaxy. Of course we haven't gone to other galaxies to check but to think this isn't the case is the galactic equivalent of thinking that the Earth is the centre of the universe.

 

Here's what wiki has to say about this particular nobody:
 
Lee Smolin (/ˈsmlɪn/; born June 6, 1955) is an American theoretical physicist, He received his Ph.D in theoretical physics from Harvard University in 1979.[2] He held postdoctoral research positions at the Institute for Advanced Study in Princeton, New Jersey, the Kavli Institute for Theoretical Physics in Santa Barbara and the University of Chicago, before becoming a faculty member at YaleSyracuse and Pennsylvania State Universities. 
 

He has made contributions to quantum gravity theory, in particular the approach known as loop quantum gravity.  His research interests also include cosmologyelementary particle theory, the foundations of quantum mechanics, and theoretical biology.

There's plenty of highly stupid highly qualified people, believe me. Anyone with memory can gain all the qualifications they like, it doesn't require any intelligence. His contributions are in an alternative model to relativity so he has a vested interest in trying to make out that sr is wrong. If sr is wrong then the speed of light isn't constant, simple as that. If the speed of light can be shown to not be constant then sr is proven wrong. If it can't be shown to be vary between inertial frames (which it can't because it is in fact, constant) then nobody has a case for refuting sr.


Edited by A-wal, 16 April 2018 - 01:01 AM.


#21 Moronium

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Posted 16 April 2018 - 04:32 AM

The topic here has been whether absolute motion can be detected.  All three of these physicists say "Yes, it can be."  According to them, the rest frame of the CMB is not just a "convenient" frame of reference, as you try to quaintly characterize it.  It is the ONLY frame which gives you the correct answer to the speed and direction of the Milky Way through "space."  That is why it's a preferred frame, because it is the only one which gives you the correct answer.

 

The use of a preferred frame in this manner destroys the theoretical foundations of SR.   Professor David Morin of Harvard has made this point very explicitly.  He says, in a footnote on page 13 of chapter eleven of his book:

 

. One might view the statement, “A sees B’s clock running slow, and also B sees A’s clock running slow,” as somewhat unsettling. But in fact, it would be a complete disaster for the theory if A and B viewed each other in different ways. A critical fact in the theory of relativity is that A sees B in exactly the same way that B sees A.

 

http://www.people.fa...orin/chap11.pdf

 

I'm sure you will be unable to grasp the significance of this.  I've already said it many times, but you are unable to comprehend it.  If I, as an observer on earth, take the position that I am moving and that a frame other than mine is "at rest."  then that is, as Morin says, "a complete disaster" for SR.  I'm sure that you don't even understand why this is a disaster, because I have already explained it to you without you without you being able to grasp a single word of it.  I'm convinced that you'll NEVER comprehend what Morin is pointing out here.  Your "understanding" of SR does not extend to an analysis of it's foundational premises.  You merely take those as being conclusively proven and hence beyond question.

 

Think about it sometime.  Think long.  Think hard  Try to understand, rather than merely robotically reciting the talking points you have been indoctrinated with.

 

In your zeal to "defend" SR, you contradict yourself glibly and without the least bit of cognitive dissonance.  Any attempt to communicate with you on this topic is doomed to futility because your blind bigotry.

 

You say, over and over and over, that "the speed of light IS constant in every inertial frame," on the one hand, for example yet end up conceding that it is not constant.  It is only measured to be constant, when it is not.  You can't even see the difference, or the significance.  You cannot simultaneously claim that the speed of light IS (ontologically) constant, while also contending that the measuring instruments on a moving object have changed in that frame with the result that the speed of light is now MEASURED to be the same in that frame.

 

I recommend that you think about it only rhetorically.  I now know you won't.  Your "thoughts" are merely the regurgitation of the litany of non sequiturs which you have been dutifully reciting for years.  It's too late for comprehension now.

 

You say:  "There's plenty of highly stupid highly qualified people, believe me. Anyone with memory can gain all the qualifications they like, it doesn't require any intelligence."

 

If the shoe fits.....


Edited by Moronium, 16 April 2018 - 05:24 AM.


#22 A-wal

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Posted 16 April 2018 - 05:44 AM

The topic here has been whether absolute motion can be detected.  All three of these physicists say "Yes, it can be."  According to them, the rest frame of the CMB is not just a "convenient" frame of reference, as you try to quaintly characterize it.  It is the ONLY frame which gives you the correct answer to the speed and direction of the Milky Way through "space."  That is why it's a preferred frame, because it is the only one which gives you the correct answer.

This is a complete misunderstanding of how frames of reference work. Yes, it is the only frame that gives the correct answer of the motion of the Milky Way through the CBM, because it's the resting frame of the CMB. IT doesn't give a "speed through space", that doesn't even make sense, speed through space depends entirely on your arbitrary choice of reference frame. I'm done trying to explain this to you, you're obviously incapable of understanding but that no reason to think that the problem is with the model, it's you.

 

One might view the statement, “A sees B’s clock running slow, and also B sees A’s clock running slow,” as somewhat unsettling. But in fact, it would be a complete disaster for the theory if A and B viewed each other in different ways. A critical fact in the theory of relativity is that A sees B in exactly the same way that B sees A.

This is entirely true, as long as both objects are inertial the situation is always symmetric. This is exactly what you get with a constant speed of light and it's been well established that it is in fact constant.

 

I'm sure you will be unable to grasp the significance of this.  I've already said it many times, but you are unable to comprehend it.  If I, as an observer on earth, take the position that I am moving and that a frame other than mine is "at rest."  then that is, as Morin says, "a complete disaster" for SR.  I'm sure that you don't even understand why this is a disaster, because I have already explained it to you without you without you being able to grasp a single word of it.  I'm convinced that you'll NEVER comprehend what Morin is pointing out here.  Your "understanding" of SR does not extend to an analysis of it's foundational premises.  You merely take those as being conclusively proven and hence beyond question.

 

Think about it sometime.  Think long.  Think hard  Try to understand, rather than merely robotically reciting the talking points you have been indoctrinated with.

OMFG! :) Sr says that every inertial frame is equivalent. You can't disprove it by the fact that any inertial observer can view themselves as inertial, that's the whole point of equivalent frames, that it makes no difference which object is at rest because all inertial motion is relative. Your 'arguments' get more and more ridiculous by the post.

 

In your zeal to "defend" SR, you contradict yourself glibly and without the least bit of cognitive dissonance.  Any attempt to communicate with you on this topic is doomed to futility because your blind bigotry.

Your hilarious!

 

You say, over and over and over, that "the speed of light IS constant in every inertial frame," on the one hand, for example yet end up conceding that it is not constant.  It is only measured to be constant, when it is not.  You can't even see the difference, or the significance.  You cannot simultaneously claim that the speed of light IS (ontologically) constant, while also contending that the measuring instruments on a moving object have changed in that frame with the result that the speed of light is now MEASURED to be the same in that frame.

The measuring instruments have to change in other frames of reference or the speed of light couldn't be constant. If objects that are in motion relative to each other both measure light to be moving past themselves at the same speed then then there has to be a difference in each ones measuring instrument from the perspective of the other. Seriously, most toddlers should be able to grasp that!

 

I recommend that you think about it only rhetorically.  I now know you won't.  Your "thoughts" are merely the regurgitation of the litany of non sequiturs which you have been dutifully reciting for years.  It's too late for comprehension now.

 

You say:  "There's plenty of highly stupid highly qualified people, believe me. Anyone with memory can gain all the qualifications they like, it doesn't require any intelligence."

 

If the shoe fits.....

You think I accept whatever mainstream science says is the truth? :) I assure you I don't.



#23 Moronium

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Posted 16 April 2018 - 06:33 AM

A-wal said"

 

The measuring instruments have to change in other frames of reference or the speed of light couldn't be constant. If objects that are in motion relative to each other both measure light to be moving past themselves at the same speed then then there has to be a difference in each ones measuring instrument from the perspective of the other. Seriously, most toddlers should be able to grasp that!

 

  

Thank you.  We finally explicitly agree on something.  Now, if you could only grasp the simple proposition that epistemology is NOT ontology, and that logical validity does not prove a posteriori soundness, then maybe we could actually get somewhere.  It's too bad that you can't take the next logical step implied by the assertions you just made.  Instead, you just continue to make ontological claims based on epistemological premises.  Tacitly, you are asserting that "whatever you measure is what is."  This is a fallacious proposition, sorry.

 

I don't "disagree" with the proposition that SR is "internally consistent."  It is.  Given the unproven postulates, the logical implications it deduces from those postulates are indeed logically valid (but not sound). That doesn't mean the implications can't be profitably used in certain limited circumstances, because they can be, even if they are unsound.  They simply cannot be "true" in an objective sense.

 

My position is simply that the implications of the premises of SR generate conclusions that CANNOT correspond to "objective reality."

 

Example of perfectly valid logic:

 

1.  All elephants are pink.

2.  This animal is an elephant.

3.  Therefore, this animal is pink.

 

As I said, perfectly valid, logically, yet completely unacceptable from the standpoint of the "soundness" of the argument.


Edited by Moronium, 16 April 2018 - 10:59 AM.


#24 Moronium

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Posted 16 April 2018 - 06:59 AM

The measuring instruments have to change in other frames of reference or the speed of light couldn't be constant. If objects that are in motion relative to each other both measure light to be moving past themselves at the same speed then then there has to be a difference in each ones measuring instrument from the perspective of the other. Seriously, most toddlers should be able to grasp that!

 

 

Your first sentence tacitly makes the unwarranted assumption that I'm getting at.  It should say "The measuring instruments have to change in other frames of reference or the speed of light couldn't be BE MEASURED TO BE constant (in that frame)."

 

Then it would be accurate.  Instead you say that it IS constant.  I have already made a series of posts addressing the simple, universally acknowledged, fact that there can be a significant  difference between "what you measure a thing to be" and "what that thing actually is."  All you did was dispute (ridicule, actually) that simple claim.


Edited by Moronium, 16 April 2018 - 07:31 AM.


#25 Moronium

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Posted 16 April 2018 - 07:19 AM

A-wal said: 

 This is entirely true, as long as both objects are inertial the situation is always symmetric.

 

No, it is not "true" in any objective sense.

 

It is true that SR posits this claim, but it is not "true" in fact.

 

Innumerable empirical observations show that time dilation is NOT reciprocal in actuality, even if it is "logically implied" by the premises of SR.

 

And again, the claim is logically impossible to begin with, so no empirical "test" is even required.

 

It is logically impossible for it to be simultaneously true that clock A is slower than clock B AND clock B is slower than clock A.  Both propositions cannot, as a matter of logic,  be "true" in any objective sense.

 

The resort to solipsistic assumptions in an absurd attempt to "justify" this claim can, as my thread title claims, only seem plausible to solpisists.


Edited by Moronium, 16 April 2018 - 10:57 AM.


#26 Moronium

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Posted 16 April 2018 - 08:34 AM

There is an interesting video on youtube where Hafele and Keating repeat their classical experiment with even more modern, more accurate, atomic clocks. 

 

At every stage of their journey they are (accurately) announcing the precise amount by which their (moving) clock differed, at that point,from the earth clock which it was synchronized with before they took off.

 

When they land, their final calculations do in fact agree with the observed difference in the clocks.

 

What the video does not reveal is that, in order to make their precise calculations, they assumed at all times that their clock was the one moving, and that therefore the earth clock was running FASTER, not slower, than their airborne clock.  In other words, they refused to adopt "reciprocal dilation" assumption of SR and the concomitant  mandate that they "assume" that they are stationary.  That would have forced them to conclude  that the earth clock was running slower than theirs, not faster.

 

The narrator in the video says they are using "Einstein's equations."  But in fact they were using Lorentz's equations.

 

The narrator also says that the result was in accord with what "Einstein predicted."  This too is inaccurate.  Einstein would have told them to "predict" that the earth clock was running slower than theirs, not faster.

 

Another thing that this video doesn't reveal is that they were not using the "relative motion" of SR to reach their (accurate) conclusions.  They were using the "absolute" motion posited by Lorentz.  Their calculations were achieved by using the ECI as a preferred frame for calculating what the difference between the readings on the earth clock and their clock would be.  In this analysis, both the earth clock and the plane clock are moving, actually.  It is the one which is moving faster (with respect to the ECI, not each other), which will run slower

 

Of course they did use Einstein's equations from GR to calculate the effect that gravitational dilation (which is absolute, not relative) would have on both clocks, since that had to be factored in also.  I was referring the the speed dilation  (Lorentz transformation) in SR above. It was the "speed" component of dilation that the moving plane was designed to test.  Of course, since the plane was flying at a higher altitude, the experiment did serve to confirm both types of dilation effects.


Edited by Moronium, 16 April 2018 - 11:08 AM.


#27 Moronium

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Posted 16 April 2018 - 10:39 AM

A-wal said:

 

The frame in which the CMB is at rest is in no way a preferred frame of reference and nobody but you is claiming that it is. You're free to use any inertial frame in which the CMB is in motion and it changes nothing because all inertial frame are equivalent.

 

  

A-wal, just to reinforce just how mistaken this claim is, I will quote the physics factbook website, which says:

 

 

In 1987, a group of seven astronomers uncovered this coordinated motion of the Milky Way and our several million nearest galactic neighbors -- Alan Dressler, Sandra Moore Faber, Donald Lynden-Bell, Roberto Terlevich, Roger Davies, Gary Wegner and David Burstein. Their results were so astounding they acquired the equally astounding nickname of "The Seven Samurai"(the name of a classic Japanese Samurai movie that spawned the classic American Western movie "The Magnificent Seven"). The place towards which we all appear headed was originally called the New Supergalactic Center or the Very Massive Object until one of the discoverers, Alan Dressler, decided they needed a catchier name and came up with "The Great Attractor".

 

The mass of the Great Attractor truly is great....it's attraction is so strong that we are being sucked into it at the rate of 600 km/s. In comparison, the earth moves around the sun at the relatively pokey rate of 30 km/s and rockets escaping the earth's gravitational pull barely move at 11 km/s.

 

 

https://hypertextboo...riciaKong.shtml

 

 

As a point of fact, cosmologists have been using the CMB as a preferred frame from which to calculate absolute motion for decades.  This practice is almost universally accepted as is Smoot's claim that the CMB is a valid universal rest frame or purposes of calculating absolute motion.  Needless to say, the proposition that absolute motion "can" be detected is also assumed, notwithstanding your denials.  You seem to be just a tad bit behind the times as far as theories of motion go, eh?

 

Notice that, among other things, the accepted "fact" is that the earth revolves around the sun, not vice versa, and certainly not "both."  As a practical matter, nobody accepts the "no preferred frame" premise of SR for everyday useage and ultimate conclusions about absolute motion, no matter how much they may otherwise claim that it is "valid."  It is assumed that absolute motion can be detected, and this can only be done by positing some frame as preferred.  "Every" or just "any" inertial frame will not suffice for this purpose, because every one will give you a different answer.  You must posit one which makes sense to treat as a preferred frame, such as the relative motionless solar barycenter for solar system purposes, as I have already pointed out. It would be inappropriate, and lead to inaccurate reults, for example, to use the CMB as a preferred frame for the purposes of calculating relative motion of the planets within the solar system.

 

I can almost hear your response now, which will be to call them all "highly stupid" like you did with Smolin because he didn't agree with your naive claims.


Edited by Moronium, 16 April 2018 - 11:17 AM.




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