On the arbitrary choice regarding which inertial reference frame is "stationary" and which is "moving" in the special theory of relativity - Douglas M. Snyder 2022 - Article review

This document contains article review "On the arbitrary choice regarding which inertial reference frame is 'stationary' and which is 'moving' in the special theory of relativity" by Douglas M. Snyder written in 2022
To order to read the abstract select: https://philpapers.org/rec/SNYOTA
To select a list of articles written by Douglas. M Snyder select this link: https://www.researchgate.net/profile/Douglas-Snyder-2

Contents

Reflection

Abstract

Einstein's argument on the relativity of simultaneity itself is the first result of the special theory of relativity.
To understand this sentence, one must understand the difference between the concepts:
simultaneous, relativity of simultaneity, and "the special theory of relativity".
This argument is reflected in the structure and functioning of the physical world.
To understand this sentence one must understand the difference between the concepts:
"structure" and "functioning" of the physical world.
The arbitrary nature of the decision regarding the particular inertial reference frame, from which the argument on the relativity of simultaneity begins, is discussed.
Why the use of the word "arbitrary"? The decision which to select should be based on scientific reasoning and experiments.
It is this arbitrary, or freely made, decision that is the basis for the significance of the argument of the relativity of simultaneity itself on the structure and functioning of the physical world.
This sentence requires a more detailed explanation.
The same concrete circumstances in the physical world can support either direction in the argument on the relativity of simultaneity, as well as other results, in the special theory.
That means the author is not convinced about what to select.
There are different sets of results in the physical world associated with the choice in direction that is made, for example as concerns the temporal durations of occurrences or the spatial lengths of existents in these inertial reference frames.
More detail is required how the results are measured. Under normal circumstances if a certain experiment is repeated the results should be the same.
Experiments testing the equations derived in the special theory that relate the temporal durations of occurrences or the spatial lengths of physical existents in inertial reference frames in uniform motion relative to one another generally have not tested predictions with both of the two inertial reference frames considered, in separate scenarios, the "stationary" reference frame.
It is proposed that empirical tests in two directions be developed and conducted.
That seems logical.
If empirical results from such tests support the predictions of the special theory, these empirical results would support the thesis that there is a cognitive factor in Einstein's argument on the relativity of simultaneity that affects results derived in the special theory concerning the physical world.
To evaluate this sentence, it is very important to know the details of the tests performed.
The special theory of relativity is also a description and evaluation of certain experiments, specific tests involving light signals.
One such test is proposed.
The most important tool to study science is by performing different experiments.
These experiments should be described in detail, such that others can repeat the same.

Reflection 1 - How to decide that a reference frame is at rest.

The topic of the article reviewed is to decide if a coordinate system is at rest or moving. To do that you have to consider at least two observers or reference frames.

First start with one observer. The observer considers himself at rest. The observer has an infinite number of rods, which all have the same length. Using his rods, he builds a 3D grid. At all the cross sections he places an identical clock. The clock operates by means of a light signal which oscillates between two mirrors. Each cycle of such a clock is considered a tick of the clock.
Next all the clocks synchronised. The general idea is first two synchronize two clocks in 1 direction. This is done by selecting a point half way between those 2 points. A light flash emitted from that point can be used to synchronize these 2 clocks. When 2 clocks are synchronized, he can use these 2 points to synchronize 4 clocks etc.
In order to test if his reference frame is at rest the observer should select 2 clocks A and B. Next, he places a third clock C near A and he synchronizes the clock C with A. The final step is to move clock C from A to B.

The underlying physical reasoning is as follows: IF you move a clock C from A to B and back A (all in straight lines) than the length of the path travelled by C is always longer than the path travelled by A (between t1 and t2). The same for the length of the path travelled by the light-signal. That means in this case clock C (the moving clock) always will show less counts than clock A.
However that does not mean that this is true for both legs of this experiment. To investigate this, a second clock is placed at the turn around point (i.e. point B). That means the single leg test should be done in both directions.

Reflection 2 - General reflection of the Article i.e. Abstract.

The title of the article is: "On the arbitrary choice regarding which inertial reference frame is "stationary" and which is "moving" in the special theory of relativity".
This title raises certain questions.
Why mention "The special theory of relativity"? Any reference book about SR mentions the words 'inertial reference frame', stationary or at rest and 'moving'. The problem is: What is specific mentioned with SR? In order to get around these difficulties, in reflection 2, I start with one reference frame, and I call this reference frame or coordinate system at rest. There is nothing wrong with this.
At the same time there can also be a second observer who also creates his own reference frame and call this frame also at rest. There is nothing wrong with this. The problem starts when two observers meet each other for a split second. In that case both cannot claim that they are at rest in the universe i.e., their reference frame.

In reflection 2 we also have one reference with two clocks A and B which are considered at there. We also have a moving clock C which can be considered at rest in its own reference frame #2. In frame #2 the two clocks A and B are moving. What you also need in frame #2 is a 'second' point D at rest in that frame. Using the two points C and D (at rest) and the moving clock A, which moves from C to D you can perform the same experiment as in reflection 1 and decide which frame is at rest.

In general, it is not easy to define a system at rest.
For our Solar System, we can consider the Sun at rest.
For our Galaxy, the Milky Way, we can consider the Black Hole Sagittarius A* at rest.
If we study the Milky Way and de Andromeda Galaxy, which both move towards each other, it should be the centre of gravity.

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Created: 17 July 2022

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