Talk:Spacetime/Archive 21

Improvements to the text

Let us look at the argument in the text, as I interpret the text:

1. If we try to analyze the scenario where source and receiver are geometrically at their closest approach to each other in the manner depicted in the current Fig. 3-7(a), we find that the analysis is more complicated than it should be. The source would be time-dilated relative to the receiver, but the redshift implied by this time dilation would be offset by a blueshift due to the longitudinal component of the relative motion between the receiver and the apparent position of the source, which differs from its actual position due to the effect of light-time correction.
2. It is much easier if, instead, we analyze the scenario from the frame of the source.

a. An observer situated at the source knows, from the conditions of the problem, that the receiver is at its closest point to him.

b. That means that the receiver has no longitudinal component of motion to complicate the analysis.

c. The receiver's clocks are time-dilated relative to the source.

d. The light that the light that the receiver receives is therefore blue-shifted by a factor of gamma.

To me, the argument in the text is straightforward. You, on the other hand, believe that the existing text is confusing. This may point to deficiencies in the text that I simply do not see. So let us see if we can work out a wording that satisfies both of us. Prokaryotic Caspase Homolog (talk) 14:16, 30 September 2018 (UTC)

Please wait a bit. I will think over my respond. It is pretty interesting.Albert Gartinger (talk) 15:10, 30 September 2018 (UTC)

Transverse Doppler Effect diagrams for moving source, moving observer and for that case, when the both move with the same but opposite velocitie.

I have depicted frame of the source and the receiver moving in it, and the receiver measures blueshift at closest approach. In the frame of the source light moves at right angle to the path of the receiver. NOTHING ELSE. It is correct WHATEWER YOU SAY. The only think is that you don’t want to attach an arrow to the observer. Because you are relativist and wish to “conduct measurements from the rest frame of the observer” i.e. to change frame and to make him “at rest”. You don’t want to admit that observer’s frame moves in the frame of the source and the observer AGREES with the fact that he moves himself but he is NOT “at rest in his own frame”. In relativity an OBSERVER never moves himself. VIP! He can only see how the others move.

If an observer “moves” he says that aberration is an apparent effect and THERE IS NO LONITUDINAL component, ONLY TRANSVERSE, when the source is “straight overhead”. We know since Bradley, that a star in zenith is not “actually” there. We can know actual position of the source if we know our velocity relative to it. If you don’t understand inertial motion, think about that observer who rotates around a source at circumference of infinitely large diameter.

I believe you make desperate attempts to fit this situation into those well – known tales. At any cost, you try to avoid the interpretation that the moving observer sees, that source's clock "at rest" ticks faster. You are absolutely blinded by dogmas. Imagine that A and B move relatively to each other. You wish to say: A sees that clock B is running slower. No, it is only a special case, as Einstein synchronization is a special case of the broader Reichenbach synchronization.

The truth is that clock A can see ANY rate of the clock B. ANY. Slower, faster, the same. That purely depends on how it measures and what it thinks about its own motion. I make the following claims and scenarios:

1) A and B have chosen one mutual frame S. In this frame A is at rest, B is in motion. B emits light backward at relativistic aberration angle. A looks at right angle towards the path of B and measures that light that was emitted when they were at closest approach. This light redshifts. A measures dilation of the clock B.

2)A and B have chosen one mutual frame S’. In this frame B is at rest, A is in motion. B emits light at right angle, A approaches the ray of light and looks into front at relativistic aberration angle sin alpha = v/c towards B and measures that light that is received at closest approach. This light blueshifts. A thinks like this: "I move relatively to B, my clock dilates, his clock ticks faster"

3) A and B have the same but opposite velocities in the mutual frame of reference. In this case they will not see ANY dilation of each other clocks. Here it is, the experiment by Champeney and Moon

http://iopscience.iop.org/article/10.1088/0370-1328/77/2/318/meta

They placed source and detector on the opposite sides of the same circular orbit and measured transverse Doppler effect, the ray of light went through the center of the circumference. Sure, they haven’t detected any frequency shift.

What if two purely inertial observers momentarily coincide with these rotating ones at the moments of reception / emission? Will they see frequency shift? Surely no, because by means of conducting measurement this way (the source emits some light backward and the observer receives this light at the same angle from the front) they choose a frame in which the both move with the same but opposite velocities.

This case is described at Mathpages perfectly well https://www.mathpages.com/home/kmath587/kmath587.htm

Again: The source moves and emits light backward at relativistic aberration angle, light comes to the observer at right angle, light is redshifted thus source’s clock ticks slower. The source is at rest and the observer moves. Source emits at right angle, light comes to the observer at relativistic aberration angle, light is blueshifted, hence source’s clock ticks faster. The source and the observer move at equal but opposite velocities. The angles of emission / reception will be the same.

Amount of time dilation belongs to the both observers; it flows from one observer to another as sand in a sand clock. We can assign it either to the source or to receiver or to the both in equal proportions. We cannot assign it to the both, it is rubbish.

There is an animation, please, don’t rush, watch carefully https://www.youtube.com/watch?v=hnphFr2Iai4

Sincerely yours, Albert Gartinger (talk) 16:45, 30 September 2018 (UTC)

By the way, please pay your attention, that from the point of view of moving observer distances in the frame at "rest" elongate, since his measuring rod Lorentz contracts. That goes straight from relativistic aberration formula. Relativistic aberration tilts position of the source further and further away, at velocity close to c an observer sees the source that is overhead almost on the horizon. While light travels distance ct, moving observer travels distance vt. Since his ruler Lorentz contracts, distance vt turns into vt multiplied by \gamma. Please look for relativistic aberration in Feynman lectures, very simple http://www.feynmanlectures.caltech.edu/I_34.html Albert Gartinger (talk) 17:17, 30 September 2018 (UTC)

1. I am quite familiar with Champeney and Moon, thank you.
2. This talk page is "for discussing improvements to the Spacetime article. This is not a forum for general discussion of the article's subject."
3. I will therefore not spend time discussing statements of yours such as, "The truth is that clock A can see ANY rate of the clock B. ANY. Slower, faster, the same." Although Robert Burns wrote, O wad some Pow'r the giftie gie us / To see oursels as ithers see us, the frame-jumping arguments and the mixed-frame illustrations that you employ only lead to confusion.
4. You are welcome to bring up your concerns to sci.physics.relativity. I occasionally contribute to discussions there.

Prokaryotic Caspase Homolog (talk) 17:55, 30 September 2018 (UTC)

If you are quite familiar with Champeney and Moon, for what purpose you conduct subjective editing and one-sided presentation of facts? It is not in accordance with WP:NPOW, or neutral point of view. You are writing propaganda - style articles instead. I wish to complain to ranking board, how to do that? I will also conduct publicity campaign against your diagram in the article by means of direct mail campaign Albert Gartinger (talk) 18:18, 30 September 2018 (UTC)

Please note that my analysis is solidly backed by published works of Nobel prize winners Albert Einstein and Richard Feynman, published works by Champeney and Moon, RC Jennison etc, Kevin S. Brown (Mathpages). What is source of your diagram? David Morin, nobody knows who is that chap.Albert Gartinger (talk) 18:29, 30 September 2018 (UTC)

It seems very silly to resist so fiercely adding an arrow to the observer and make it moving. Smells badly for you? That's that. I will turn the whole article into a piece of smelly shit.Albert Gartinger (talk) 18:34, 30 September 2018 (UTC)

I will ask my secretary to prepare a list of target audience. I will send thousand, or tens of thousands of emails. I have enough time. Albert Gartinger (talk) 18:37, 30 September 2018 (UTC)

Final warning on user talk page. - DVdm (talk) 18:54, 30 September 2018 (UTC)

A static image poorly displays process. The problem is in the angle of perception and emission, which are different. I'll create dynamic animation. Of course, for the case A, the transverse effect will be animated in the reference frame of the source at rest, as it should be, that is, the observer will move. This will eliminate any doubts of any viewer, even a child. Nobody will be able shamelessly fool the audience. The world is changing; new methods of presentation are emerging. Albert Gartinger (talk) 14:08, 1 October 2018 (UTC)

Making an animation is fine, providing it clarifies points that a static diagram illustrates poorly. Just don't mix up elements from two frames into a single image. Keep the frames separated, as pictured here. Prokaryotic Caspase Homolog (talk) 20:03, 1 October 2018 (UTC)

I have learned from our communication what mistakes I have made in the diagram. First, direction of rotation must be the same, as direction of motion corresponding inertial observer. If moving inertial observer move to the left, rotating observer moves clockwise. This way nobody would dare forcibly force him to stand (please excuse me for tartness).

If moving inertial source moves to the right, then rotating source must rotate clockwise. There is a mistake in direction in rotation now.

This way it will be clear, that rotating and inertial observers are almost the same. We can say that inertial observer moves at circumference of infinitely large diameter. The rotating one sees blueshift, and the moving sees blueshift. The rotating one looks into front, and inertial one looks into front either, at the same relativistic aberration angle.

Second. I must show directions of emission/reception. Arrow on the bulb (a red or green source inside) must be oriented in that direction, where light comes from. For "stationary observer" light comes from the top, but the source has the same arrow which points (emits) backward. For "moving observer" light comes at oblique angle from the front, but the source emits at right angle (transverse Doppler effect in the frame of the source).

I will redraw them tomorrow. I believe they will be the best at the moment.

Third: Your "tricky" diagram is correct, but it is not Transverse Doppler effect. This is longitudinal Doppler effect. An observer can treat any effect doubly:

I am at rest, there is longitudinal component, or I am in motion, there is only transverse component.

Actually there are perfect animations of transverse Doppler effect in youtube

Transverse Effect Simply explained https://www.youtube.com/watch?v=hnphFr2Iai4

Transverse or longitudinal effect https://www.youtube.com/watch?v=FQKp3FU8vR8

Albert Gartinger (talk) 20:46, 1 October 2018 (UTC)

An observer can make himself "stationary" or moving in very simple way. Just by turning his head. He looks at right angle towards direction of motion of the source, and measures redshift (Ives - Stilwell, Hasselkamp experiments). Then he ascribes himself state of motion and due to aberration turns his head into front at relativistic aberration angle and measures blueshift (Kundig experiment for rotating absorber). He interprets this blueshift as purely transverse effect (dilation of his own clock. Since his clock dilates, source's clock runs faster and radiation blueshifts. Reciprocal time dilation of special relativity only because nobody confesses, that he moves. Everyone looks at source at right angle. It is nonsense. One of them must look at right angle, the other at oblique angle. Then one will see redshift, the other will see blueshift (reflecton of transversely moving mirror) Logic and order. In closed system, if they neither lose nor gain energy from outside, they CANNOT see dilation of each other clocks. Albert Gartinger (talk) 21:07, 1 October 2018 (UTC)

Please take your original research to sci.physics.relativity. It does not belong on these talk pages. Prokaryotic Caspase Homolog (talk) 21:33, 1 October 2018 (UTC)

@Albert Gartinger: indeed, this must stop here. This is the place where we can discuss changes to the article based on reliable wp:secondary sources. Youtube clips do not qualify. This entire discussion is Wikipedia-technically off-topic here—see wp:Talk page guidelines. And again, see wp:No original research. - DVdm (talk) 07:48, 2 October 2018 (UTC)