A person will see their wrist watch count normally irrespective of their motion, non-inertial or otherwise.
Correct and I have never said otherwise and what does this response have to do with my satatement that he is only at rest if inertial?.
Observers in relative motion see one anothers clock tick at different rates. When they move into the same frame they will find they have measured different periods of time. Precisely who measured what and by how much depends on the specifics of their worldlines.
Correct. What they see during relative motion may but most likely will not be supported by data in the final analysis. Predictions of time accumulation while in motion will only be correct if one was at rest and remainded at rest.
And then it will only be correct for the resting observer not the traveling observer. The traveling observer's view that the resting clock is dilated will not be supported.
Time dilation is a somewhat cumulative process, you can put something into relative motion, bring it to rest and you'll have a measure of the difference in time passing. Measuring length changes is more difficult because it can only be done, in the case of inertial motion, by using straight paths and getting anything up to a significant fraction the speed of light in a straight line and then doing an experiment on it requires very very large bits of equipment. Even at 10% the speed of light you're out of the atmosphere and into space in a fraction of a second if you move in a straight line.
Yes even contraction of a rod would be difficult to measure but it is important to recall that once motion has stopped there is no change in length so it is very much simular to the reciprocity predicted by SR for time dilation which also does not occur in the resting frame.
But the real isssue I raise is that of spatil contraction that is a change in distance. As I have posted here many times now that is proven to be a false concept.
If you go 1/2 the distance in 1/2 the accumulated time at the same speed then your clock must have remained ticking at the original rate and hence the resting clock and traveling clock remain in sync and when the twin returns the resting clock must have accumulated the same amount of time as the traveling clock; hence no time dilation would have occured.
Since time dilation does occur then spatial contraction is proven false.
I am not an experimentalist but I'd wager that such things as beam length contraction is seen in such places as CERN when doing collisions. I'll ask someone tomorrow. But your claim 'no empirical evidence' is not something I'd accept. The fact you haven't found any doesn't mean there isn't any and even if there isn't, that's different to being falsified.
I will wait to see those claims of spatial contraction. Again there is a difference. I too accept contraction of mass or rods but not space.
So the plethora of experiments where SR is tested you ignore?
Not at all. They are for the most part valid. There are a few that have been promoted that really have questionable results that have been masssaged to make unsupported claims. i.e. - H&K atomic clock test. That is not to deny time dilation but just to say the final published report with claims data does not match the raw data collected.
In fact a secret memo to the US Navy that sponsored the test was gotten via FOIA (The Freedon of Information Act) where the H&K experimentors said the data was disappointing and proved nothing.
We can't drill to the centre of the Earth to check its made of Nickel and Iron, doesn't mean we throw out geology. We can't test the Standard Model at the Planck scale, doesn't mean we throw it out. There are plenty of regimes in which particular bits of mainstream science can't be tested due to cost, difficultly, lack of technology or being impractical. So we do what we can and in that regard, SR is a resounding success.
Not the same issue. Geology gives it's best assumption based on test data. But geology does not then also say the earth has a hollow core. That is claim something for which it has no evidence much less proof and which is in conflict with it's own stipulation that the core onsists of iron, etc.
In SR they stipulate that a clock is dilated but then go to the dilated frame and claim the clocks tick the same and hence the lesser accumulated time is because he traveled less distance.
If they simply retain their initial dilated clock stipulation in the traveling frame then you will see just what my diagrams show which is that spatial contraction fails to produce the predicted SR results.
Your hypocrisy is in calling other people egotistical.
You haven't been here almost (6) years and had to put up with James R's assertion that he is so much smarter than anybody that disagrees with him. I have.
I am full well ready to change my view if he or anyone answers my charges in a direct valid way but whzt you get is called a Crank, Crackpot, ignorant, incapable of learning, childish first grader,etc., instead of any real discussion.
I have been accused of being unable of doing grade school math when I have repeatedly posted correct calculations using relativity time dilation, length contraction, gamma, etc., not to mention I have had nuclear engineering.
So I have had to put up with a lot of personal abuse at the hands of egotistical people like James R that believe if you don't accept his view ofSR then you are ignorant and incapable of learning.
You say that as if noone understands SR and just blindly accepts it. Do you think this is generally the case?
No. I believe most relativists fully understand the mathematics and the testing that has been done. But they refuse to look at the consequences of the theory in areas not tested or not supported by empirical data.
Degree in pure and applied mathematics, followed by a 4th year Certificate of Advanced Study of Mathematics, Trinity College, Cambridge. Currently in 3rd year of theoretical physics PhD, researching non-geometric vacua of string theory. Published. Courses taught to undergrads includes 'relativity and motion' and 'quantum mechanics'.
Are you saying this is your background? If so then yu superceed mine but I do have considerable formal training as well. Which isn't really at issue. The issue is basic physics and spatial contraction voids time dilation at the physical level (not the verbal or mathematical level).
Is this your whining? Yes, there are pairings of worldlines which will experience the same proper time, despite having relative motion. Relativity doesn't say otherwise. Neither of the people in your example are inertial, if you consider a third observer who is then they'll be dilated by the same amount relative to that person.
Thank you. And that is not my whinning. It is my point. The dilation is to the common rest frame and NOT between them in terms of the relative velocity they once had to each other.
By the looks of it you have not actually done any relativity and instead have badly pieced together a number of results from different thought experiments and found them to be conflicting. The usual twin thought experiment is a very very simple particular case of a much more complicated set of results. If everyone is moving non-inertially or involves accelerations which are perhaps less 'nice' than instantaneous changes then you cannot expect to make use of the simplified results of less convoluted situations.
This seems a bit off. You would have to be a bit more specific about what you think I am doing or have done because it doesn't sound like anything I would agree to.
I have simply taken the assertions of SR and put them to the test. For example if you accept spatial contraction accdording to SR then a person accelerating AWAY from earth will reach a point where the faster he RECEEDS the CLOSER he gets to earth.
I suspect you never realized that bit of nonsense is unavoidable in SR.
Given two worldlines $$x^{\mu}(\lambda)$$ and $$y^{\mu}(\lambda)$$ for $$\lambda \in [\lambda_{0},\lambda_{1}]$$ with $$x^{\mu}(\lambda_{0})=y^{\mu}(\lambda_{0})$$ relativity doesn't say that it's impossible for the following condition to be satisfied : $$x^{\mu}(\lambda_{1})=y^{\mu}(\lambda_{1})$$ with $$|\dot{x}^{\mu}(\lambda)-\dot{y}^{\mu}(\lambda)|>0$$. In your case you just use reflectional symmetry. It's true for any spherical symmetry case, where you obtain $$y^{\mu}$$ by an O(n) transformation on $$x^{\mu}$$ which leaves $$x^{\mu}(\lambda_{1})$$ unchanged (can you tell me the name of this subgroup? Or is that question over your head?).
Frankly no, math is not my forte'. I am not a physicist or mathematician. My issue and point do not depend on those, it depends on the very simple facts as stated.
Now I have had calculus 45 years ago but haven't ever really needed to use it and do not even pretend any more. So higher mathematics is not my thing but neither am I completely lost reading most papers because I have had some math and a lot of physics.
Now I have not attacked SR mathematics have I, so why should I be impressed by any? The problem is not mathematical. The problem is SR is based on an error in the postulates and the application of those postulates into a purely mathematical contrivence mostly devoid of any real physics.
The results have utility and can be used to make predictions but only if you disregard the ludricrus claims about relative velocity being a a cause of physical change.