Relativity and simple algebra II

I never said anything to the contrary. I explain what is the cause of that physical reality differently than SR does. You're whole point seems to be shifting. At first it was length contraction is the only possible explanation for the electricity and magnetism videos I posted if you put them in some sort of circular experiment and now your point is my explanation for twin paradox age difference is somehow impossible in this circular experiment which I have yet to see.

 

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Wait, you're now using this to support your circular argument. HK is a straight up round trip twin paradox example. There would be no time difference between the plane and a guy at the center of the Earth because there is no relative velocity between them. At the surface, the circular trip can be linearized into a straight out and back in trip so you really can't be serious including this as part of your argument.

 

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Then realize you are claiming that everyone in that PSE article: https://physics.stackexchange.com/q...of-light-in-uniform-circular-motion-of-source
, here's another one: https://physics.stackexchange.com/q...-to-test-general-relativity?noredirect=1&lq=1
(which goes into an explicit derivation from SR first principles), ALL of them are wrong in your opinion!
What's more, that every experiment claiming unambiguous confirmation of Transverse Doppler shift age slowing for objects in steady circular motion is somehow wrong! Basically all the experimentalists there are frauds or at best really stupid!

No. Sorry to say it's your grasp of basic kinematics, we're not even talking SR here, that is woefully inadequate. In #313 I wrote:

"There is always relative velocity of v = ω × r between the orbiting twin B and stay at home twin A located anywhere on the orbit axis z. Whats more it's obvious that relative motion is always exactly normal to the radius line r connecting B to A."
The expression for relative velocity v there is correct, however I should have stipulated the r in that vector expression is the radius line applying in the plane of rotation, and only coincides with the radius line joining A to B if A is also in the plane of rotation. At some distance h away the plane but still on the axis of rotation z, the radius line r' A to B will have length sqrt(r^2 + h^2), but that has no effect on relative velocity v.

At this point I have about given up on you. One last reference to try and shake your above quoted ridiculous claim out of you:
https://en.wikipedia.org/wiki/Circular_motion
If you cannot grasp or refuse to accept the essentials laid out there, what's left to discuss?

 

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Suppose a ball bearing is set in motion with some initial speed u around an ideally frictionless horizontal circular race track of radius r. After a period T = 2πr/u the ball bearing completes exactly one full circuit and so on repetitively. At the center of the track an observer declares 'the ball remains at the same distance r from me, therefore it has no relative velocity or speed wrt me'.

Out of nowhere, a bystander furnishes a 'relative motion test kit', comprised of a light plastic ball, of or about the same size as the much heavier ball bearing. Just after the rolling ball bearing passes the bystander, he/she deftly places the plastic ball motionless on the track. Motionless we note also wrt the observer at the center of track. After a time of almost T, the circulating ball bearing collides with and dislodges the plastic ball 'test kit'. The centered observer now has to explain how the ball bearing could have sent the plastic ball flying if there is in fact no relative motion between himself/herself and the circulating ball bearing. A puzzling chain of events. Eventually it dawns - there must be relative motion after all!

All along, the problem was the centered observer thought only motion along a line directly toward or away from him could count as relative motion. That purely transverse relative motion was just as legitimately relative motion was learned the long way around. Better late than never one hopes.

 

I'm not closing the door to eventually seeing the light but for now I'll continue unconvinced. Even if I assume you're correct, I'm still unconvinced that this example proves length contraction is real or that it disproves my explanation of time dilation or permanent age difference. All I can do is talk about this with others, as I did with the electricity/magnetism example, as I did with my very first forum question in 2006 which took years to resolve. I'd like to post it on the PSX but they kick you off if you ask a question you don't already know the answer to. I'll take a look at the latest links you've provided.

 

Fine. All I ask is check carefully what I have already written beginning p12 #237 before putting any words in my mouth. Take extra care not to misrepresent me! I've suffered spades of that at the hands of various others here and it's very off-putting!

 

Ok for now I'm just going to continue on with what I was doing.

As long as Q brought up pet peeves on forums, I have 2. One is Q did not answer some of my questions and 2 is when I take the trouble to answer questions and there is no subsequent response. Where did Neddy Bate go? James wanted to see how the cheese is made, what's behind that nice even accelerating slope of the Loedel lines of simultaneity during the velocity imbalance period. I mean, I could have just made it up to make it look like my math was working. Here's the explanation in Md form:

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The light signal from Alice to Bob is the duration of the velocity imbalance period. On the left are light green signals that represent the Loedel lines of simultaneity before Alice stops. On the right are light green signals representing the Loedel lines of simultaneity after Alice stops. Where they intersect the light signal forms a triangle with the resultant dark green lines of simultaneity that connect the proper times showing how the proper time age difference is unfolding during the imbalance period.

 

I find the same true of everyone else. No one understands the difference between closing speed, relative velocity or even what velocity means. If someone is neither approaching or receding from you in a direct line, there is no relative velocity between you. That's why you can walk much slower across the surface of the earth and maintain zero relative velocity with a satellite in space if you are walking on the same radius line. Your angular velocity is the same but your relative velocity is zero. That's why the brief instant that a bullet is right beside you, in between the time it is changing from approach to recession, that bullet is at zero relative velocity to you in that instant. Do you disagree with everything I've just said?

 

I haven't posted here in ages, but I do read the posts in these Science/Physics/Math forums. But I'm pretty sure I can resolve the difference that Q-reeus and raifcis have in Q-reeus' circular motion thought experiment, so I'm going to speak out right-or-wrong:

The difference has to do with the action of the person in the center, the person that you are lead to believe is "supposedly motionless WRT all of this". Neither Q-reeus nor raific said what that person is to do or how he is to observe the ball bearing.

If you stipulate that the person in the center has to keep his gaze fixed on a distant object, then there will be relative motion between that person and the ball bearing circling him. Instead, if that person rotates on his axis, to keep that ball bearing in sight at all times, there will be no relative motion. That is born out by the 2nd part of Q-reeus' scenario, where a 3rd object is made to enter the circle of the ball bearing, only to have the ball bearing collide with it next circuit. I think it goes like this: The person in the center is certainly not in relative motion to the 3rd object, and there is certainly motion between the ball bearing and 3rd object, so how can the person in the center and the ball bearing not be in relative motion?

That is easily resolved by if the person in the center is rotating along with the ball bearing, then there is relation motion between him and the 3rd object but not the ball bearing. If the person in the center constantly gazes at the 3rd object, then there is relative motion between him and the ball bearing, but not the 3rd object. And so the relative motion between the ball bearing and 3rd object doesn't present any problems.

 

Nope, still 0 relative velocity to the center of your body. Also if you were at the north pole, you can spin around much faster than someone on the equator can go around but that's not relative velocity. Even if you sank down the z-axis of the earth, at no time are you engaged in relative velocity with someone at the equator except while you're sinking because you're distance to the guy at the equator is shrinking in a direct line. Put someone in the center of a fast enough centrifuge and you've invented a time machine? Oh okay.

 

You are still neglecting to consider that the person in the center is in motion if he is rotating, whether or not there is no distance gained between that person's center of body and the object circling.

 

All kinds of motions that are not relative velocity, the cause of time difference.

 

Which brings to mind that you might want to read up on Circular Motion, and a couple of concepts called "Newton's Bucket", (and it even delves into an abhorrent (un-aesthetic, to me) concept called "Mach's Principle"). If you look close at the "Newton's Bucket" thought experiment, it is not really different than what I used to come to conclusion with in my post #329 of the differences you and Q-reeus had in his thought experiment. I'm not quite sure why you say it is wrong. Your post #330 is not convincing as you didn't say anything about the (circular/absolute) motion of the person at the center.

BTW, the person that is in rotation in the center -- it doesn't really matter if that person is actually in the center of rotation of the "outside" object (ball bearing in Q-reeus' example), or orbiting somewhere else outside that center. The same thing is observed. You posted as much in your post #328.

So, here is the link -- I hope it helps: https://en.wikipedia.org/wiki/Absolute_rotation

 

I don't see the relevance of your link as there is no centrifugal force involved.

 

You didn't read good enough. Centrifugal force is a basis of explanation. I actually don't think you read it at all.

 

I read the whole damn thing. Not scanned, read in case any part of the article had any relevance. Force is absolute motion, it is not relative motion. We are talking about relative velocity. Centripetal force is due to acceleration coming from the changes in direction. The HafelKeating experiment involves no force except for gravity which is factored out. Just how much physics do you actually know or is it a passing philosophical curiosity to you.

 

From the link I provided:

"Centrifugal force is needed to explain the concavity of the water in a co-rotating frame of reference (one that rotates with the water) because the water appears stationary in this frame, and so should have a flat surface."

Which is quite a bit different from your post #335: "I don't see the relevance of your link as there is no centrifugal force involved."

Centrifugal force is certainly evolved in circular motion.

 

A guy at the center of the Earth is going to feel no force between him and people on the surface who are being flung away unless he has a rope attached to one and is windmilling her over his head. How much physics have you studied again? I didn't catch your response.

 

Neither is a person orbiting the Earth.

 

Right so your first statement is false.