Simplifying Einstein's Thought Experiments

[Ed Lake]

Since it is 26 pages long, I'm thinking I should have titled my new
paper "REVIEWING Einstein's Thought Experiments." If I was
"simplifying" them, the paper shouldn't have been more than 2 pages
long.

But it "simplifies" the experiments by going through them step by
step and performing the same experiment in different ways so that
the results can be compared and analyzed. And it uses virtually NO
mathematics.

I'd be very much interested in any thoughts anyone might have here
about how to improve my paper titled "Simplifying Einstein's Thought
Experiments." Here's the link: http://vixra.org/pdf/1805.0251v1.pdf

Ed

[Torn Rumero DeBrak]

Why should the dropped stone of "Dropped Stone Experiment #2." move
to the head of the train, when hitting the ground? It would NOT.

Rethink your Thought-experiment.

[Ed Lake]

[Moderator's note: I have set followups to the poster. -P.H.]

The dropped stone does NOT "move to the head of the train when hitting
the ground." I just didn't have a better way of illustrating that the
stone would bounce in the direction of the engine but would rapidly slow
down due to friction with the earth. It is all explained in the text.

The paper already has 27 illustrations, it would have taken one or two
more to explain that minor detail. I didn't expect anyone to be
confused by it.

Ed

[Moderator's note: Yes, it would move forward relative to the GROUND
when it bounces, as it says in the paper. However, at least if ignoring
friction, in the case of the moving train the stone would NOT take
longer to reach the ground. Also, ignoring friction, neither OT nor OE
would see it moving forward reletion to the TRAIN. Again, ignoring
friction, OT's observations would be the same even if the embankment
were moving. Since there is no new physics here, I suggest that further
comments be mailed to the original poster. -P.H.]

[Ed Lake]

On Wednesday, May 16, 2018 at 6:34:27 AM UTC-5, Torn Rumero DeBrak wrote:

It doesn't move TO the head of the train. It moves WITH the train.
It remains directly below OT until it hits the ground, then it slows
down as it bounces and moves toward the rear of the train. There's
just no easy way to show that in the illustration. I'd need more
illustrations.

Thanks for the response, though. I'll try to think of a way to
improve the Figure 3 illustration.

Ed

[Ed Lake]

On Wednesday, May 16, 2018 at 6:34:27 AM UTC-5, Torn Rumero DeBrak wrote:

[John Heath]

The laws of physics are the same for all FoR. If train speed is .87
c then the stationary observer must see the ball fall from the
moving train at 1/2 it's normal speed. This is necessary for the
moving observer on the train to have his ball falling at the correct
speed according to his clock that is time dilated running at 1/2
it's normal speed.

If the stationary observer were to drop a ball would the moving
observer on the train see the ball fall twice as fast? Hmmm.

[Ed Lake]

I've made the corrections people have recommended, and I added a
new Experiment #11 to address a key issue. Here's the latest version
of "Simplifying Einstein's Thought Experiments":
http://vixra.org/pdf/1805.0251v3.pdf

I'd really like to get people's thoughts on this.

Ed

[Nicolaas Vroom]

On Tuesday, 15 May 2018 20:12:13 UTC+2, Ed Lake wrote:

> I'd be very much interested in any thoughts anyone might have here
> about how to improve my paper titled "Simplifying Einstein's Thought
> Experiments." Here's the link: http://vixra.org/pdf/1805.0251v1.pdf
>
> Ed

The article starts with the following sentence:

"A thought experiment (or in German: \_Gedankenexperiment_/) is a
scientific experiment which is conducted entirely in one's mind."

I have always had certain misfeelings about thought experiments, because
how you can do an experiment solely in your mind.
Ofcourse you can discuss any experiment in the development phase of a
projec with your colleques.

The next sentence reads:

"It is *snip* in that the experiment must obey all the rules of physics,"

What are the rules of physics? (Is the uncertainty principle a rule
of physics?) This can be specific be a problem if you want to challange
a certain existing law.

The next sentence reads:

"Einstein's train-embankment experiments, for example, involve a train
(snip) that travels at about thirty or forty percent of the speed of
light."

This sentence raises a serious problem and it is related to the issue
how to perform an experiment in your mind.
What is the reason that the experiement is not done at 0.001% of the
speed of light? and how do you know in that case that the experiment
is done at 0.001% of the speed of light.
The problem is that it is relatif simple to perform this experiment in
your mind, but very difficult in reality?
What exactly (physical) means 0% of the speed of light?

The next sentence reads:

"The experiment is not really about trains (or embankments), *SNIP* and
what another observer would see from a stationary location as the vehicle
passes close by."

Again here: how can you do this in your mind.
In most cases the prediction is that different observers will see
something different. The issue is which observer has the correct view
about the reality. Is that the 'stationary' or 'moving' observer and
are all the moving observers equally wrong? Maybe all are wrong.

At page 3 we read:
"Something is correct if it agrees with the laws of physics and has been
demonstrated to be correct by experiments. "

I would rewrite this as such:
A certain prediction is correct when it is demonstrated by experiments.
(not thought experiments).
The descriptions of these predictions we call the law of physics.

This terminates my contribution.

Nicolaas Vroom

[richali...@gmail.com]

On Wednesday, June 20, 2018 at 3:00:26 PM UTC-5, Nicolaas Vroom wrote:
> On Tuesday, 15 May 2018 20:12:13 UTC+2, Ed Lake wrote:
>
> > I'd be very much interested in any thoughts anyone might have here
> > about how to improve my paper titled "Simplifying Einstein's Thought
> > Experiments." Here's the link: http://vixra.org/pdf/1805.0251v1.pdf
> >

[Moderator's note: Quoted text snipped. -P.H.]

Thought experiments can not be used to learn anything about the world,
only to gain insight into the laws of physics as you understand them.
Einstein's though experiments about the train allow you to understand
the implications of the assumption that the speed of light is a constant
for all observers, even observers moving wrt each other. These
"experiments" prove nothing by themselves except what the assumptions
imply. You still have to do real world experiments to verify that the
real world gives the same results as the thought experiment. If they do
not, then there is a faulty assumption somewhere. The value of the
thought experiment is to understand the implications of an hypothesis
(i.e. assumption).

Rich L.

[Nicolaas Vroom]

On Thursday, 21 June 2018 21:04:56 UTC+2, richali...@gmail.com wrote:
> On Wednesday, June 20, 2018 at 3:00:26 PM UTC-5, Nicolaas Vroom wrote:
> > On Tuesday, 15 May 2018 20:12:13 UTC+2, Ed Lake wrote:
> >
> > > I'd be very much interested in any thoughts anyone might have here
> > > about how to improve my paper titled "Simplifying Einstein's Thought
> > > Experiments." Here's the link: http://vixra.org/pdf/1805.0251v1.pdf
> > >
>
> [Moderator's note: Quoted text snipped. -P.H.]
>
> Thought experiments can not be used to learn anything about the world,
> only to gain insight into the laws of physics as you understand them.

> Einstein's though experiments about the train allow you to understand
> the implications of the assumption that the speed of light is a constant
> for all observers, even observers moving wrt each other.

This sentence describes one possible assumption.
A different assumption is: that the physical speed of light is local
the same in all directions, assuming that no gravity is involved.
This implies that the speed of light is comletely observer independent.
A different assumption could be to consider an observer on earth at rest
and that the speed of light in his frame is the same in all directions.
Such an assumption makes the issue observer dependent

IMO a thought experiment can not decide which one is right or wrong.

> You still have to do real world experiments to verify that the
> real world gives the same results as the thought experiment.

IMO that is the real strategy to follow. Study real world experiments,
give the details of how they are performed and try to understand them
(based on certain assumptions if required).

Nicolaas Vroom.

[Ed Lake]

On Thursday, June 21, 2018 at 2:04:56 PM UTC-5, richali...@gmail.com wrote:
> On Wednesday, June 20, 2018 at 3:00:26 PM UTC-5, Nicolaas Vroom wrote:
> > On Tuesday, 15 May 2018 20:12:13 UTC+2, Ed Lake wrote:

< snip >

Einstein's thought experiments produced papers which showed that
time is variable: The faster you travel, the slower time advances
for you, i,e., the slower your clocks will tick, the slower you
will age, the slower your hair will grow, etc. It took a long time
for actual experiments to confirm that. But they did.

Einstein's thought experiments about time also showed that if clocks
tick slower when they move faster, then the ether is "superfluous"
(i.e., "not needed"), since you can measure how fast you are going
relative to someone else by the difference in tick rates for identical
clocks.

If you have five people with identical clocks traveling at five
different speeds, their clocks will tick at five different rates.
You can rank the five by their relative speeds - A is moving faster
than B, B is moving faster than C, C is moving faster than D, and
D is moving faster than E.

Unfortunately, when Einstein said he made the ether "superfluous,"
some people inexplicably interpreted that to mean that motion is
reciprocal, i,e., if I am moving faster than you in my frame of
reference, you are moving faster than me in your frame of reference.
And no matter how many ways you show that belief to be absurd, they
still believe it.

Ed

[Dirk Van de moortel]

Op 23-jun-2018 om 11:15 schreef Ed Lake:

> On Thursday, June 21, 2018 at 2:04:56 PM UTC-5, richali...@gmail.com wrote:
>> On Wednesday, June 20, 2018 at 3:00:26 PM UTC-5, Nicolaas Vroom wrote:
>>> On Tuesday, 15 May 2018 20:12:13 UTC+2, Ed Lake wrote:
>
> < snip >
>
> Einstein's thought experiments produced papers which showed that
> time is variable: The faster you travel, the slower time advances
> for you, i,e., the slower your clocks will tick, the slower you
> will age, the slower your hair will grow, etc. It took a long time
> for actual experiments to confirm that. But they did.
>
> Einstein's thought experiments about time also showed that if clocks
> tick slower when they move faster, then the ether is "superfluous"
> (i.e., "not needed"), since you can measure how fast you are going
> relative to someone else by the difference in tick rates for identical
> clocks.
>
> If you have five people with identical clocks traveling at five
> different speeds, their clocks will tick at five different rates.
> You can rank the five by their relative speeds - A is moving faster
> than B, B is moving faster than C, C is moving faster than D, and
> D is moving faster than E.
>
> Unfortunately, when Einstein said he made the ether "superfluous,"
> some people inexplicably interpreted that to mean that motion is
> reciprocal, i,e., if I am moving faster than you in my frame of
> reference,

You don't move in your frame of reference.

Dirk Vdm

[Nicolaas Vroom]

On Saturday, 23 June 2018 11:15:15 UTC+2, Ed Lake wrote:
>
> < snip >
>
> Einstein's thought experiments produced papers which showed that
> time is variable: The faster you travel, the slower time advances
> for you, i,e., the slower your clocks will tick, the slower you
> will age, the slower your hair will grow, etc. It took a long time
> for actual experiments to confirm that. But they did.

What the actual experiments showed is that not all physical clocks
behave the same.
Considering a physical clock which use lightsignals and assuming
the clock at rest. In such a case it is easy to explain by means
of a sketch that a second identical moving clock ticks slower.

> If you have five people with identical clocks traveling at five
> different speeds, their clocks will tick at five different rates.
> You can rank the five by their relative speeds - A is moving faster
> than B, B is moving faster than C, C is moving faster than D, and
> D is moving faster than E.

The first issue is that you should consider your five clocks from one
reference frame.
The second issue is to answer the question: which clock ticks the slowest.
This raises immediate an new issue: is it possible
to introduce a sixth clock which ticks more slower?
The answer could be: that clock should have a slower speed.
This pops up a new question: How is the speed of each clock
measured?
To measure the speed you need clocks, which makes this discussion
more complex and somewhat circular (if that is the good wording)

In any way you can not solve this problem by means of a thought
experiment.

Nicolaas Vroom

[Tom Roberts]

On 6/23/18 11:15 AM, Ed Lake wrote:
> Einstein's thought experiments produced papers which showed that time is
> variable: The faster you travel, the slower time advances for you, i,e., the
> slower your clocks will tick, the slower you will age, the slower your hair
> will grow, etc.

This is just plain not true, and Einstein's thought experiments and papers show
no such thing.

These thought experiments describe Special Relativity (SR), which predicts that
no matter how you might move (relative to anything), your clocks tick at their
usual rate, you age at your usual rate, your hair grows at its usual rate, etc.
-- all as measured BY YOU (as your words say).

The underlying reason for this prediction is very basic: the first postulate of
SR says that the laws of physics are the same in every inertial frame. So the
laws that govern the ticking of your clocks, your ageing, and the growing of
your hair, are ALWAYS THE SAME in your rest frame, regardless of how your frame
might be moving (relative to anything). Since the laws are the same, the
ticking, ageing, and growth rates must all be the same, TO YOU (i.e. as measured
in your rest frame).

> It took a long time for actual experiments to confirm that. But they did.

Hmmm. Experiments have NOT confirmed what you said above, but they have
confirmed many times the ACTUAL predictions of SR. This includes "time
dilation": clocks tick at their usual rate when measured in their rest frame,
and are observed to tick more slowly by observers relative to whom they are moving.

[Note that in SR this is due to the geometrical relationship
between relatively-moving inertial frames, and not any effect
on the intrinsic tick rate of clocks.]

> [... further confusions and incorrect claims]

These thought experiments describe and illuminate Special Relativity. In order
to improve the quality and accuracy of your paper about them, first you must
learn what Special Relativity ACTUALLY predicts. At present, your paper is
completely useless because it describes YOUR mistakes and confusions, not
Einstein's thought experiments and theory.

[A major error is thinking that some observations are "correct"
and others are "incorrect" (in your unusual sense that they are
consistent with the laws of physics). So for a stone dropped from
a moving train, on page 5 you claim the embankment observation is
"correct" while the on-train observation is "incorrect". You have
failed to grasp the first postulate, and the FACT that the relevant
laws of physics are INDEPENDENT of frame -- BOTH descriptions are
"correct" (in your unusual sense of consistent with the known laws;
it's just that you did not apply the ACTUAL laws as they are known).
How can an observation possibly be "incorrect"?? -- after all,
observers observe what they observe. Even with your unusual
meaning of "correct", how can an observer possibly violate the
laws of physics???]

Tom Roberts

[Ed Lake]

On Friday, June 29, 2018 at 2:28:03 AM UTC-5, Tom Roberts wrote:

< snip >

> These thought experiments describe and illuminate Special Relativity. In order
> to improve the quality and accuracy of your paper about them, first you must
> learn what Special Relativity ACTUALLY predicts. At present, your paper is
> completely useless because it describes YOUR mistakes and confusions, not
> Einstein's thought experiments and theory.
>
> [A major error is thinking that some observations are "correct"
> and others are "incorrect" (in your unusual sense that they are
> consistent with the laws of physics). So for a stone dropped from
> a moving train, on page 5 you claim the embankment observation is
> "correct" while the on-train observation is "incorrect". You have
> failed to grasp the first postulate, and the FACT that the relevant
> laws of physics are INDEPENDENT of frame -- BOTH descriptions are
> "correct" (in your unusual sense of consistent with the known laws;
> it's just that you did not apply the ACTUAL laws as they are known).
> How can an observation possibly be "incorrect"?? -- after all,
> observers observe what they observe. Even with your unusual
> meaning of "correct", how can an observer possibly violate the
> laws of physics???]

If a moving observer notices no difference in the passing of time in his
reference frame, but then COMPARES his time to the time of a non-moving
observer, there will be a difference. The moving observer's time passed
at a slower rate.

So, his view that there was "no difference" in the passing of time while
he was moving was INCORRECT. There WAS a difference. Time passed at a
slower rate while he was moving.

If the moving observer drops a stone and sees it fall straight down,
while a stationary observer sees that stone fall in a parabolic curve,
their conflicting views cannot both be "correct."

The view that the stone falls straight down is INCORRECT because that
view fails to notice the effects of inertia.

If the two observers sit down and discuss what they saw, they will agree
that the stone did not and could not fall straight down from a moving
train. So, that view was "incorrect." It was an "illusion."

It is also an "illusion" that you age at your "normal" rate when moving
fast. That "illusion" is understood when the moving and stationary
observers sit down together and compare what happened. The faster you
move, the slower time passes for you - even though you notice nothing
different happening.

Einstein made that very clear in his 1905 paper: "Thence we conclude
that a balance-clock at the equator must go more slowly, by a very small
amount, than a precisely similar clock situated at one of the poles
under otherwise identical conditions."

You move faster at the equator due to the spin of the earth. You can
argue that the slightly flattened shape of the earth actually offsets
that effect, but Einstein was using a "thought experiment" which
involved a perfectly spherical Earth.

Ed

[Tom Roberts]

On 6/29/18 5:32 PM, Ed Lake wrote:
> If a moving observer notices no difference in the passing of time in
> his reference frame, but then COMPARES his time to the time of a
> non-moving observer, there will be a difference.

Yes.

> The moving observer's time passed at a slower rate.

No. All known laws of physics are valid in the "moving observer's"
frame, with their standard constants, so time passes at its usual rate
for him -- one second is still 9,192,631,770 oscillations of CS-133.

A major part of your problem is saying "moving observer" without saying
what he is moving with respect to. You are implicitly attempting to use
some "absolute" or "God's eye" view of the world. That's invalid, as
there is no such thing in modern physics.

Do you seriously think a train embankment is at rest
in some "absolute" sense????

> If the moving observer drops a stone and sees it fall straight down,
> while a stationary observer sees that stone fall in a parabolic
> curve, their conflicting views cannot both be "correct."

This is simply not true. Both observers observe what they observe. Both
MUST be correct.

But in your paper you attempt to redefine "correct" to mean "consistent
with the laws of physics", and seem to be using that here. Leaving aside
the absurdity of such unusual redefinitions, it is not possible for
either observer to violate the laws of physics, so again, BOTH
OBSERVATIONS MUST BE CORRECT.

> The view that the stone falls straight down is INCORRECT because
> that view fails to notice the effects of inertia.

There's your problem -- you do not understand the laws of physics. Here,
in the context of Newtonian physics, there is no "law of inertia", there
are just:
* conservation of energy
* conservation of momentum
* Newton's three laws
* Newton's law of universal gravitation
BOTH observations are fully consistent with all of these.

All of these laws are valid in EVERY inertial frame. So they
are valid in the frame of the embankment, and they are ALSO
valid in the frame of the train. (The initial conditions of
the stone are different in these frames, fully accounting
for the difference in observations.)

> [... further incorrect claims based on the same error]

> Einstein made that very clear in his 1905 paper: "Thence we conclude
> that a balance-clock at the equator must go more slowly, by a very
> small amount, than a precisely similar clock situated at one of the
> poles under otherwise identical conditions."

This is one of his (minor) errors in that paper. In 1905 nobody knew
that the earth is an oblate spheroid, and the effect of that exactly
cancels the effect of the motion due to rotation, when comparing clocks
to the Earth Centered Inertial frame. He also did not specify how
the comparison is made -- in 1905 it was not understood that this is
essential; today it is.

> [... further incorrect claims based on the same error]

You MUST learn to avoid implicitly using "God's eye", as there is no
such thing in modern physics. Practically everything you write does
that, making it wrong. You cannot understand relativity, or
intelligently discuss Einstein's thought experiments, without abandoning
"God's eye" and learning what SR actually says. Your paper discusses
YOUR OWN MISTAKES, not Einstein's thought experiments or theory.

Redefining a basic word like "correct" OUGHT to be
a big red flag that you are doing something wrong.

Tom Roberts

[Ed Lake]

On Sunday, July 1, 2018 at 10:29:01 AM UTC-5, Tom Roberts wrote:
> On 6/29/18 5:32 PM, Ed Lake wrote:
> > If a moving observer notices no difference in the passing of time in
> > his reference frame, but then COMPARES his time to the time of a
> > non-moving observer, there will be a difference.
>
> Yes.
>
> > The moving observer's time passed at a slower rate.
>
> No. All known laws of physics are valid in the "moving observer's"
> frame, with their standard constants, so time passes at its usual rate
> for him -- one second is still 9,192,631,770 oscillations of CS-133.
>
> A major part of your problem is saying "moving observer" without saying
> what he is moving with respect to. You are implicitly attempting to use
> some "absolute" or "God's eye" view of the world. That's invalid, as
> there is no such thing in modern physics.

It's clearly stated. The moving observer was moving relative to the
"non-moving observer."

>
> Do you seriously think a train embankment is at rest
> in some "absolute" sense????

No one suggested that. You are creating baseless arguments. It
simplifies things to refer to an embankment as being "stationary" even
though in the grander scheme of things it is traveling around the Milky
Way galaxy at 486,000 miles per hour. The "grander scheme of things"
isn't part of the discussion.

> > If the moving observer drops a stone and sees it fall straight down,
> > while a stationary observer sees that stone fall in a parabolic
> > curve, their conflicting views cannot both be "correct."
>
> This is simply not true. Both observers observe what they observe. Both
> MUST be correct.

Another baseless argument. Observers observe what they observe, but
that doesn't automatically make anything "correct." A man a block away
may appear smaller than someone a foot away, but that doesn't mean it is
"correct" to say that the person a block away is actually smaller than
the man next to you.

> But in your paper you attempt to redefine "correct" to mean "consistent
> with the laws of physics", and seem to be using that here. Leaving aside
> the absurdity of such unusual redefinitions, it is not possible for
> either observer to violate the laws of physics, so again, BOTH
> OBSERVATIONS MUST BE CORRECT.

Obviously not. It violates the "conservation of momentum" for a stone
dropped from a moving vehicle traveling parallel to the earth's surface
to fall straight down. So, the observation that the stone traveled in a
parabolic arc is the "correct" observation.

> > The view that the stone falls straight down is INCORRECT because
> > that view fails to notice the effects of inertia.
>
> There's your problem -- you do not understand the laws of physics. Here,
> in the context of Newtonian physics, there is no "law of inertia", there
> are just:
> * conservation of energy
> * conservation of momentum
> * Newton's three laws
> * Newton's law of universal gravitation
> BOTH observations are fully consistent with all of these.
>
> All of these laws are valid in EVERY inertial frame. So they
> are valid in the frame of the embankment, and they are ALSO
> valid in the frame of the train. (The initial conditions of
> the stone are different in these frames, fully accounting
> for the difference in observations.)
>
> > [... further incorrect claims based on the same error]

Within two closed inertial frames of reference *experiments* work
identically. HOWEVER, when one frame of reference is observed from
another frame of reference, the experiments may not work identically.
The same laws are valid in EVERY inertial frame, but they can produce
different results if one frame is moving relative to the other. The laws
involve variables, such as the length of a second.

< snip > pointless argument

> You MUST learn to avoid implicitly using "God's eye", as there is no

> such thing in modern physics. < snip > more of the same.

No one but you is saying anything about "God's eye." Einstein's theory
says that if B is moving faster than A, then time will move slower for
B. And if C is moving faster than B, then time will move slower for C
than for B. And if D is moving faster than C, then D time will move
slower for D than for A, B and C. Etc., etc., etc.

There is no "God's eye" involved. Einstein just said that a
"luminiferous ether" is "superfluous" if the faster an object travels,
the slower time passes for that object. Time comparisons can be used to
determine who is moving faster than whom. That works until the speed of
light is reached, at which point time stops for the object moving at
that speed.

Ed

[Edward Prochak]

For the Gedanken experiment, time comparisons cannot be used
to determine who is moving, period. You are almost there
with your descriptions that used letters instead of train and
embankment.

So, I like to pose the experiment as 2 trains with windows
only on the side facing the other train. Nothing else to
reference. Tracks and embankments are out of sight.
Of course also extremely smooth ride, not vibrations to
indicate movement.

We can even imagine both trains are infinitely long,
or at least long enough to conduct our thought experiments.

Each car of both trains contains an observer, watching
the other train and and an experimenter conducting an
experiment to watch.

The trains move at speed V relative to the other.

Experiment 1
In one of the cars of train A, the experimenter drops
a ball. The observer in train B also records the
experiment.

Experiment 2
In one of the cars of train A, the experimenter shoots
a ball at speed V in the same direction as train B.
The observer in train B also records the experiment.

Experiment 3
In one of the cars of train B, the experimenter drops
a ball. The observer in train A also records the
experiment.

Experiment 2
In one of the cars of train B, the experimenter shoots
a ball at speed V in the same direction as train A.
The observer in train A also records the experiment.


SO what do they conclude?
Both conclude that a ball falls at a given rate
(the acceleration of gravity).

Both agree that when they drop a ball in their
own train, it falls straight down. and the both
agree that combined motions work the same within
their own train.

The same goes for light and time.

Particular observations may be different,
but are symetrical.

IOW, they agree that the laws of physics are the same
in both trains. If they published ballistics tables,
both trains would come up with the same results.

They do disagree on who is moving, and
no experiment can tell them the "correct" answer.
There is no "illusion" to dispel.

Ed

[Tom Roberts]

On 7/1/18 2:52 PM, Ed Lake wrote:
> On Sunday, July 1, 2018 at 10:29:01 AM UTC-5, Tom Roberts wrote:
>> On 6/29/18 5:32 PM, Ed Lake wrote:
>>> If the moving observer drops a stone and sees it fall straight down,
>>> while a stationary observer sees that stone fall in a parabolic curve,
>>> their conflicting views cannot both be "correct."
>>
>> This is simply not true. Both observers observe what they observe. Both
>> MUST be correct.
>
> Another baseless argument.

No, it is not "baseless" at all -- that is what those words mean.

Have you never been on a train and dropped something while it is en route? -- if
not, go find a train and do it (or use a car).

It is QUITE CLEAR that a dropped object on a train falls straight down RELATIVE
TO THE TRAIN [#]. And it is also QUITE CLEAR that the same object falls in a
parabolic arc RELATIVE TO THE EMBANKMENT. BOTH observations are correct, because
that is what those observers actually observe.

NOTE: I reject and ignore your outrageous attempt to redefine the word
"correct". Instead, I will write out your meaning, "consistent with the laws
of physics". Such egregious redefinitions only serve to obscure the argument and
confuse the participants.

[#] Here the context is Newtonian physics, and I ignore
the distance the train travels during the fall compared
to the radius of the earth. That is, here gravity points
straight down, even though on earth it actually changes
direction slightly as the train moves. I do this to
avoid getting bogged down in irrelevant minutiae. Note
that a more careful analysis that includes this does NOT
change the basic conclusion.

> Observers observe what they observe, but that doesn't automatically make
> anything "correct."

Sure it does, because that is what those words mean. Both observer's
observations are also consistent with the laws of physics. After all, no
observer or physical phenomenon can possibly violate those laws.

You claim that the train observer's observation is not consistent with the laws
of physics -- how do you suppose that the train observer or the stone can
violate those laws?????

Hint: If it is possible to violate them, then they aren't
really "laws of physics".

> So, the observation that the stone traveled in a parabolic arc is the
> "correct" observation.

Sure, RELATIVE TO THE EMBANKMENT. But it is not the only correct observation --
the observation of the train observer is also correct. Both are also consistent
with the laws of physics.

> Within two closed inertial frames of reference *experiments* work
> identically. HOWEVER, when one frame of reference is observed from another
> frame of reference, the experiments may not work identically.

This is nonsense. You do not understand what frames of reference actually are.

A frame of reference is a set of coordinates relative to which an experiment can
be DESCRIBED. The frame is PURELY IN THE MIND OF THE ANALYST, and used FOR
DESCRIPTION ONLY; nature does not use frames in any way. So whichever frame is
used by the analyst/observer, that choice cannot possibly affect the results of
the experiment (here the trajectory of the falling stone).

The trajectory of the stone before it is dropped is important to how the laws of
physics determine its trajectory after it is dropped. But the fact that it is
initially at rest in the train frame is IRRELEVANT to those laws [@], and to the
its subsequent trajectory. But being initially at rest in the train frame is
important to the DESCRIPTION of the stone's trajectory relative to the train
frame. Similarly, the initial forward motion of the stone relative to the
embankment frame is IRRELEVANT to those laws [@], and to its subsequent
trajectory, but is important to the DESCRIPTION of the stone's trajectory
relative to the embankment frame.

[@] Because the laws of physics are INDEPENDENT of frame;
nature does not use frames in any way.

IOW: the dropped stone moves in a fashion determined by the laws of physics.
Those laws can be described in ANY frame of reference, and necessarily must give
THE SAME trajectory of the stone -- after all there is only one stone and it is
dropped only once, so it can have only one trajectory. If the laws are accurate,
they MUST predict this one trajectory, and must do so using ANY frame of reference.

The train observer describes the stone as falling straight down, and the
embankment observer describes it as falling in a parabolic arc. BOTH
descriptions are correct (in that they accurately describe what is observed by
each observer), BOTH descriptions describe the ONE trajectory of the stone (from
different perspectives using different frames), and BOTH descriptions are
consistent with the laws of physics.

> The same laws are valid in EVERY inertial frame, but they can produce
> different results if one frame is moving relative to the other.

Hmmmm. The laws of physics are INDEPENDENT of frame, and they yield a result
that is INDEPENDENT of frame (I use the normal meaning of "result"). But the
DESCRIPTIONS of the result using different frames can certainly be different.

If by "result" you mean the normal "what actually happened", then your statement
here is just plain wrong; if by "result" you intend the unusual meaning
"DESCRIPTION of what actually happened", then of course different frames can
yield different descriptions.

[Do not expect me to continue. You clearly do not understand
very basic concepts of physics, or even basic English usage.
It is useless to try to continue until you learn the basics.]

Tom Roberts

[Ed Lake]

You create experiments where no one can detect any differences in the
results of the experiments, and then you claim that means that no one
can detect any differences in the results of the experiments.

What is the point of such self-proving experiments? If you remove all
means of telling who is moving and who is not, obviously you will not be
able to tell who is moving and who is not. It's an absurd experiment.

Einstein's theories say that if you perform your experiments inside an
inertial reference frame, you will get the same results as someone else
inside a different inertial reference frame moving at a different speed.
So, you created a complicated set of experiments to prove what everyone
already knows.

The point of Relativity, however, is that, if you have a situation where
you CAN tell who is moving and who is not, or who is moving faster than
whom, then the laws of physics will still be the same, the tests will
still produce the same results, but you can see that while the results
APPEAR identical, they are actually different because they used a
variable: the length of a second. Thus, the test results are actually
different and definitely NOT symmetrical. The comparison between frames
will show that one is moving faster than the other and therefore one
used longer seconds than the other.

In Einstein's thought experiments he specifically says that you can open
the window and SEE who is moving and who is not, even though you cannot
tell that when the windows are closed.

Ed

[Ed Lake]

If you set down a rule that you cannot tell what is correct and what is
incorrect, what is the point? Science and physics is about determining
what is correct and what is incorrect.

You argue, "Because the laws of physics are INDEPENDENT of frame; nature

does not use frames in any way."

Correct. But HUMANS use frames. And they can APPEAR to get the same
results in different "frames" while actually getting very different
results. That is what Relativity is all about.

If they can compare the length of a second as used in their different
frames, they will find that they used different lengths for seconds.
The length of a second is a variable in the laws of physics. It is a
COUNT of "periods of the radiation corresponding to the transition
between the two hyperfine levels of the ground state of the cesium 133
atom."

If within your lab you count 9,192,631,770 such periods, you consider it
to be one second. I do the same in my lab. But if we can compare
clocks, we can find that you reached a total of 9,192,631,770 periods
long before did. Thus our seconds are actually of different lengths,
even though we both consider a second to have same length:
"9,192,631,770 periods of the radiation corresponding to the transition
between the two hyperfine levels of the ground state of the cesium 133
atom."

Time passes slower for whichever object is moving faster. You can prove
that by comparing length of seconds on atomic clocks. They work the
same way as cesium 133 atoms and all other atoms. They tick at a
specific rate that slows down when they move faster. And they stop when
they reach the speed of light.

Ed

[Edward Prochak]

> > Experiment 2(4)

> > In one of the cars of train B, the experimenter shoots
> > a ball at speed V in the same direction as train A.
> > The observer in train A also records the experiment.
> >
> >
> > SO what do they conclude?
> > Both conclude that a ball falls at a given rate
> > (the acceleration of gravity).
> >
> > Both agree that when they drop a ball in their
> > own train, it falls straight down. and the both
> > agree that combined motions work the same within
> > their own train.
> >
> > The same goes for light and time.
> >
> > Particular observations may be different,
> > but are symetrical.
> >
> > IOW, they agree that the laws of physics are the same
> > in both trains. If they published ballistics tables,
> > both trains would come up with the same results.
> >
> > They do disagree on who is moving, and
> > no experiment can tell them the "correct" answer.
> > There is no "illusion" to dispel.
> >
> > Ed
>
> You create experiments where no one can detect any differences in the
> results of the experiments, and then you claim that means that no one
> can detect any differences in the results of the experiments.

I created a gedanken experiment that mirrors reality, such as
two planet earths passing each other in remote space.

>
> What is the point of such self-proving experiments? If you remove all
> means of telling who is moving and who is not, obviously you will not be
> able to tell who is moving and who is not. It's an absurd experiment.

No it is what we actually face in astronomical studies.
We can use earth as our reference frame, but that does not
mean we represent the embankment of the experiment.

>
> Einstein's theories say that if you perform your experiments inside an
> inertial reference frame, you will get the same results as someone else
> inside a different inertial reference frame moving at a different speed.
> So, you created a complicated set of experiments to prove what everyone
> already knows.

Good. It is not more complicated, just clearer as to the real situation
we face.

>
> The point of Relativity, however, is that, if you have a situation where
> you CAN tell who is moving and who is not, or who is moving faster than
> whom, then the laws of physics will still be the same, the tests will
> still produce the same results, but you can see that while the results
> APPEAR identical, they are actually different because they used a
> variable: the length of a second. Thus, the test results are actually
> different and definitely NOT symmetrical. The comparison between frames
> will show that one is moving faster than the other and therefore one
> used longer seconds than the other.

Not symmetrical as to the details. But the results that both
derive are the same, namely: the laws of gravity and inertia
and E&M are the same.

>
> In Einstein's thought experiments he specifically says that you can open
> the window and SEE who is moving and who is not, even though you cannot
> tell that when the windows are closed.
>
> Ed

But the conclusion derived from the experiment is that there
is NO preferred frame. Your comments about "correct" path of
an object is the mistaken impression that I hoped this
example would demonstrate. If you think there is a "correct"
path for a dropped ball to fall, then using the results of
the four experiments tell us which train is not moving
and which train is moving.

Then consider a real example, the relative motions of
the Milky Way galaxy and the Whirlpool galaxy.
Which galaxy is not moving and which one is moving?
Please kindly share how you reach your conclusion.
Oh one caveat: no fair using a third reference frame,
such as the CMBR or Galactic clusters or God's eye view.

Enjoy,
Ed

[Tom Roberts]

On 7/3/18 1:34 PM, Ed Lake wrote:
> If you set down a rule that you cannot tell what is correct and what
> is incorrect, what is the point? Science and physics is about
> determining what is correct and what is incorrect.

To see the absurdity of your claims, just unwind your VERY UNUSUAL AND
OUTRAGEOUS meaning of "correct":

Ed Lake said: If you set down a rule that you cannot tell what
is consistent with the laws of physics and what is inconsistent
with the laws of physics, what is the point?

It OUGHT to be clear that NOTHING we observe can be inconsistent with
the laws of physics -- we and any physical process we observe are
necessarily constrained by those laws. I did not "set down a rule" that
is not already contained in the phrase "laws of physics".

Ed Lake said: Science and physics is [sic] about determining
what is consistent with the laws of physics and what is
inconsistent with the laws of physics.

The absurdity of this is manifest -- EVERYTHING we observe is consistent
with the laws of physics, there is no possibility of "determining".

[Note also that everything we observe is correct (standard
meaning) -- it simply is not possible to make incorrect
observations. It is possible to interpret observations
incorrectly, and when that happens competent scientists
fix the error.]

In fact, science and physics are about modeling the world we inhabit. We
have learned that the phrase "the laws of physics" is a chimera, and
today we formulate MODELS, not "laws". For the simple reason that we now
know that humans can never know the actual Laws used by Nature, the best
we can possibly do is to approximate them, and that is not at all the same.

Also note that when you attempt to redefine common words, you confuse
yourself and your readers. DON'T DO THAT.

> You argue, "Because the laws of physics are INDEPENDENT of frame;
> nature does not use frames in any way."
> Correct. But HUMANS use frames. And they can APPEAR to get the same
> results in different "frames" while actually getting very different
> results. That is what Relativity is all about.

No, that is NOT "what relativity is all about", because your previous
sentence is blatantly false.

When we use different frames to DESCRIBE an experiment, the RESULT is
unchanged -- for the example being discussed there is ONE stone, it is
dropped ONCE, and it has ONE trajectory -- THAT TRAJECTORY IS THE RESULT
OF THE EXPERIMENT. But of course the train and embankment observers
describe this trajectory differently, using their different= perspectives.

> [... further nonsense that ignores the lessons above.]

Tom Roberts

[Ed Lake]

> > > They do disagree on who is moving, and=20

> > > no experiment can tell them the "correct" answer.
> > > There is no "illusion" to dispel.
> > >
> > > Ed

> >=20

> > You create experiments where no one can detect any differences in the
> > results of the experiments, and then you claim that means that no one
> > can detect any differences in the results of the experiments.

>=20

> I created a gedanken experiment that mirrors reality, such as
> two planet earths passing each other in remote space.

> >=20

> > What is the point of such self-proving experiments? If you remove all

> > means of telling who is moving and who is not, obviously you will not b=

e
> > able to tell who is moving and who is not. It's an absurd experiment.

>=20

> No it is what we actually face in astronomical studies.
> We can use earth as our reference frame, but that does not
> mean we represent the embankment of the experiment.

>=20
> >=20

> > Einstein's theories say that if you perform your experiments inside an
> > inertial reference frame, you will get the same results as someone else

> > inside a different inertial reference frame moving at a different speed=

.
> > So, you created a complicated set of experiments to prove what everyone
> > already knows.

>=20

> Good. It is not more complicated, just clearer as to the real situation
> we face.

> >=20
> > The point of Relativity, however, is that, if you have a situation wher=

e
> > you CAN tell who is moving and who is not, or who is moving faster than
> > whom, then the laws of physics will still be the same, the tests will
> > still produce the same results, but you can see that while the results
> > APPEAR identical, they are actually different because they used a
> > variable: the length of a second. Thus, the test results are actually

> > different and definitely NOT symmetrical. The comparison between frame=

s
> > will show that one is moving faster than the other and therefore one
> > used longer seconds than the other.

>=20

> Not symmetrical as to the details. But the results that both
> derive are the same, namely: the laws of gravity and inertia
> and E&M are the same.

>=20
> >=20
> > In Einstein's thought experiments he specifically says that you can ope=

n
> > the window and SEE who is moving and who is not, even though you cannot
> > tell that when the windows are closed.

> >=20
> > Ed
>=20

> But the conclusion derived from the experiment is that there
> is NO preferred frame. Your comments about "correct" path of
> an object is the mistaken impression that I hoped this
> example would demonstrate. If you think there is a "correct"
> path for a dropped ball to fall, then using the results of
> the four experiments tell us which train is not moving
> and which train is moving.

>=20

> Then consider a real example, the relative motions of
> the Milky Way galaxy and the Whirlpool galaxy.
> Which galaxy is not moving and which one is moving?
> Please kindly share how you reach your conclusion.
> Oh one caveat: no fair using a third reference frame,
> such as the CMBR or Galactic clusters or God's eye view.

>=20
> Enjoy,
> Ed

You seem to have fundamental misunderstandings of Relativity.
Everything in our observable universe is moving. So, the question
"Which galaxy is not moving and which is moving?" is absurd and
meaningless. The question should be: Which galaxy is moving FASTER
than the other? The same with the moving trains: Which is moving
FASTER than the other?

You ask absurd, meaningless questions. According to Einstein's
Special Theory of Relativity, there is no need for a "lunimiferous
ether" to use as a "preferred reference frame" to measure all
movement against. Instead, you can measure all movement by how
slow clocks tick. The faster an object moves, the slower a clock
on that object will tick.

So, clocks aboard an object will tick slower and slower as the
object moves faster and faster, until the speed of light is reached.
At the speed of light, time stops. You cannot go faster than the
speed of light. That is one key to understanding Einstein's Special
Theory of Relativity.

If you have two trains moving at different speeds, experiments
aboard those trains will produce identical results even though time
moves at different rates aboard the two trains. And you cannot
tell that time is moving at different rates unless you compare clock
rates. Then you will see that, while both clocks tick 9,192,631,770
times per second, the clock aboard the slower moving train will
reach that count long before the clock aboard the faster moving
train. The faster a train moves, the slower clocks will tick aboard
that train.

That is the other key to understanding Einstein's Special Theory
of Relativity.

Ed

[[Mod. note -- Many of your statements need to be qualified with
who (which observer or frame-of-reference) is making the observation:

Notably, your question "Which galaxy is moving FASTER than the other?"
has different answers depending on the observer or frame-of-reference.

Also notably, "clocks aboard an object" will be observed *by a
"co-moving" observer who is also aboard the same object* to tick at
precisely their normal rate.

-- jt]]

[Ed Lake]

On Friday, July 6, 2018 at 6:38:32 PM UTC-5, Tom Roberts wrote:
> On 7/3/18 1:34 PM, Ed Lake wrote:
> > If you set down a rule that you cannot tell what is correct and what
> > is incorrect, what is the point? Science and physics is about
> > determining what is correct and what is incorrect.
>
> To see the absurdity of your claims, just unwind your VERY UNUSUAL AND
> OUTRAGEOUS meaning of "correct":
>
> Ed Lake said: If you set down a rule that you cannot tell what
> is consistent with the laws of physics and what is inconsistent
> with the laws of physics, what is the point?
>
> It OUGHT to be clear that NOTHING we observe can be inconsistent with
> the laws of physics -- we and any physical process we observe are
> necessarily constrained by those laws. I did not "set down a rule" that
> is not already contained in the phrase "laws of physics".
>
> Ed Lake said: Science and physics is [sic] about determining
> what is consistent with the laws of physics and what is
> inconsistent with the laws of physics.
>
> The absurdity of this is manifest -- EVERYTHING we observe is consistent
> with the laws of physics, there is no possibility of "determining".
>
> [Note also that everything we observe is correct (standard
> meaning) -- it simply is not possible to make incorrect
> observations. It is possible to interpret observations
> incorrectly, and when that happens competent scientists
> fix the error.]

< snip > more of the same.

So, if the world appears flat, then it is flat - because it is what
we observe? And if it appears that the sun goes around the earth,
then that must be correct because it is what we observe? And if
the earth beneath our feet appears motionless, then it must be so
- because "it simply is not possible to make incorrect observations"?

Hmm. Then what is the purpose of science? I thought it was to
explain inconsistencies in observations. The earth appears flat,
yet ships somehow disappear over the horizon. The sun appears to
go around the earth, but observations of other planets indicate
they orbit around the sun. The earth beneath my feet feels motionless,
but if I am inside a vehicle moving at a constant rate, the floor
beneath my feet also feels motionless, even though I know I am
moving.

All those inconsistencies can be resolved by understanding the laws
of physics. Gravity enables a spherical world to APPEAR locally
flat. The sun is vastly larger than the earth, thus its greater
gravity requires that the earth orbit around the sun. The earth
beneath my feet feels motionless ("stationary") because the earth
and I are moving in unison in the same direction at the same speed.

A stone dropped from a moving train cannot drop straight down because
inertia will cause it to move with the train until gravity stops
it. The observation that the stone fell straight down was "incorrect"
because it was inconsistent with the laws of physics. When you
understand how events can APPEAR inconsistent with the laws of
physics while still obeying the laws of physics, then all observers
can agree on what actually happened.

Ed

[Ed Lake]

[Moderator's note: Huge amount of quoted text deleted. Please quote
only enough to provide sufficient context. -P.H.]

What I am trying to explain is that time moves slower when an object
moves faster. And when you reach the speed of light, time stops.
Period. That is what Einstein's Theory of Special Relativity says.

The speed of light can be used as a "preferred" reference frame.

When you talk about "frames of reference" where observers are imagined
to be "stationary," you create a FICTION where each observer sees the
other observer as moving.

Instead, you should do as Einstein recommended and have the observers
COMPARE the tick rates of their clocks. The clock that is moving the
fastest will tick at the slowest rate. Thus, instead of fantasizing
that you are stationary and the other observer is moving, you can
determine who is ACTUALLY moving faster than whom.

The only objects that are "stationary" in our observable universe are
objects that move at the same speed in the same direction. Their clocks
will tick at the same rate, so they are "stationary" relative to one
another, even if both are traveling at 486,000 miles per our around the
center of the Milky Way galaxy.

Ed

[Edward Prochak]

On Saturday, July 7, 2018 at 9:35:41 PM UTC-4, Ed Lake wrote:

> All those inconsistencies can be resolved by understanding the laws
> of physics. Gravity enables a spherical world to APPEAR locally
> flat. The sun is vastly larger than the earth, thus its greater
> gravity requires that the earth orbit around the sun. The earth
> beneath my feet feels motionless ("stationary") because the earth
> and I are moving in unison in the same direction at the same speed.
>

Note there is an assumption above that is not explicitdly stated:
That the laws of the universe are consistent everywhere.

> A stone dropped from a moving train cannot drop straight down because
> inertia will cause it to move with the train until gravity stops
> it. The observation that the stone fell straight down was "incorrect"
> because it was inconsistent with the laws of physics. When you
> understand how events can APPEAR inconsistent with the laws of
> physics while still obeying the laws of physics, then all observers
> can agree on what actually happened.
>
> Ed

You still persist in this "correct'/"incorrect" paradigm
that begs for a god-like reference frame.

you are right, unless, of course, the train is
standing still on the tracks! ;)
Or in my two train example,
both trains move with the same velocity.

Ed P.

[Edward Prochak]

IOW, you can only measure speeds relative to some other frame.
You cannot, in the real universe, open the train window
to see some at rest embankment, because both the window
and the embankment are not there.

>
> You ask absurd, meaningless questions.

Your comments about "correct" motion of the ball prompted
my question. So it seems reasonable to ask you: which
observer in which train observers the "corect" path
of motion according to you?

> According to Einstein's
> Special Theory of Relativity, there is no need for a "lunimiferous
> ether" to use as a "preferred reference frame" to measure all
> movement against. Instead, you can measure all movement by how
> slow clocks tick. The faster an object moves, the slower a clock
> on that object will tick.

I did not mention nor do I see a need for "lunimiferous ether".
I totally agree that in SR, moving clocks run slower.
Why would you suggest I accept any other conclusion?

>
> So, clocks aboard an object will tick slower and slower as the
> object moves faster and faster, until the speed of light is reached.
> At the speed of light, time stops. You cannot go faster than the
> speed of light. That is one key to understanding Einstein's Special
> Theory of Relativity.

Yes, no object there. I hope you have a point.

>
> If you have two trains moving at different speeds, experiments
> aboard those trains will produce identical results even though time
> moves at different rates aboard the two trains. And you cannot
> tell that time is moving at different rates unless you compare clock
> rates. Then you will see that, while both clocks tick 9,192,631,770
> times per second, the clock aboard the slower moving train will
> reach that count long before the clock aboard the faster moving
> train. The faster a train moves, the slower clocks will tick aboard
> that train.

Still nothing new. Still also avoiding my question.

>
> That is the other key to understanding Einstein's Special Theory
> of Relativity.
>
> Ed
>
> [[Mod. note -- Many of your statements need to be qualified with
> who (which observer or frame-of-reference) is making the observation:
>
> Notably, your question "Which galaxy is moving FASTER than the other?"
> has different answers depending on the observer or frame-of-reference.
>
> Also notably, "clocks aboard an object" will be observed *by a
> "co-moving" observer who is also aboard the same object* to tick at
> precisely their normal rate.
>
> -- jt]]

Yes the entire point of the two train gedanken experiment
is to emphasize that there is no preferred frame of reference.
this is something that the wording Ed prefers to use about
"correct" results is meaningless in SR. So I am basically
Asking Ed Lake which frame of reference will produce his
"correct" results.

Ed P.

[Tom Roberts]

On 7/7/18 8:35 PM, Ed Lake wrote:
> [... much silliness omitted] A stone dropped from a moving train cannot drop

> straight down because inertia will cause it to move with the train until
> gravity stops it.

You repeatedly omit important information in your descriptions. Here you omitted
WHO is doing the observing. To the train observer, the stone DOES drop straight
down [#]; to the embankment observer it does not. BOTH are correct (in that this
is indeed what they observe). BOTH are consistent with the laws of physics (how
could they not???).

(And, of course, "gravity" does not stop it, the floor of
the train stops its fall.)

[#] Ignoring the distance the train moves during the fall
compared to the radius of the earth; I also omit many details.

> The observation that the stone fell straight down was "incorrect" because it
> was inconsistent with the laws of physics.

Not true (ignoring your OUTRAGEOUS AND UNUSUAL meaning of "incorrect"). The
train observer's observation that the stone fell straight down is fully
consistent with the laws of physics. You clearly do not know what those laws
ACTUALLY are.

Hint: If an observation is inconsistent with the "laws of
physics", then those "laws" MUST BE WRONG. After all, that
is what science is.

Here are two different DESCRIPTIONS of a single fall of the stone, by two
observers using two different inertial frames and Newtonian mechanics; they
apply THE SAME law of physics (F=ma). Both begin when the stone is dropped [#]:

Embankment observer: The force of gravity F points straight down, and I apply
F=ma to the stone with mass m; the initial condition is the stone's initial
velocity in the train's forward direction relative to my embankment frame, and
the trajectory is a parabolic fall relative to my embankment frame (constant
horizontal velocity, accelerating downward).

Train observer: The force of gravity F points straight down, and I apply F=ma to
the stone with mass m; the initial condition is the stone's initial velocity of
zero relative to my train frame, and the trajectory is a fall straight down
relative to my train frame (zero horizontal velocity, accelerating downward).

Newton's second law, F=ma, is a differential equation that
can be solved for the position of an object in terms of an
inertial frame's coordinates. Applying this equation requires
initial conditions, which must of course be expressed in terms
of the frame used. It applies to ANY inertial frame within the
domain of Newtonian mechanics (e.g. NOT to Einstein's thought
experiments).

[This has wandered very far from Einstein's thought experiments, and it is
useless to continue until you improve the precision of your thinking and
writing, and also learn some very basic physics. Goodbye.]

Tom Roberts

[Ed Lake]

On Monday, July 9, 2018 at 2:13:03 PM UTC-5, Edward Prochak wrote:
> On Saturday, July 7, 2018 at 9:35:41 PM UTC-4, Ed Lake wrote:
>
>> All those inconsistencies can be resolved by understanding the laws
>> of physics. Gravity enables a spherical world to APPEAR locally
>> flat. The sun is vastly larger than the earth, thus its greater
>> gravity requires that the earth orbit around the sun. The earth
>> beneath my feet feels motionless ("stationary") because the earth
>> and I are moving in unison in the same direction at the same speed.
>>
>
> Note there is an assumption above that is not explicitdly stated:
> That the laws of the universe are consistent everywhere.

If you want it explicitly stated, here it is: As far as we know, the
laws of the universe are consistent everywhere. (However, the laws
include variables - such as time and the length of a second. So, the
laws work consistently with the variables to produce the same results
every time. However, due to the variables the actual results can be
different when you compare results obtained under difference
time-related conditions (when one body is moving faster than the
other).)

>
>> A stone dropped from a moving train cannot drop straight down because
>> inertia will cause it to move with the train until gravity stops
>> it. The observation that the stone fell straight down was "incorrect"
>> because it was inconsistent with the laws of physics. When you
>> understand how events can APPEAR inconsistent with the laws of
>> physics while still obeying the laws of physics, then all observers
>> can agree on what actually happened.
>>
>> Ed
>
> You still persist in this "correct'/"incorrect" paradigm
> that begs for a god-like reference frame.

No, it just requires being able to tell the difference between what is
"real" and what is an "illusion." You may think that the train you are
on is stationary and the railroad station and embankment outside are
moving, but that is just an "illusion." If you understand that energy
was required to make the train move, and the amount of energy used by
the engine could not possibly make the planet move while the train
stands still, then you can understand how to tell the difference between
an "illusion" and reality.

Of course, it can be argued that it is also an "illusion" that the
embankment and station are standing still, since both are moving as the
earth spins on its axis and travels around the center of the galaxy at
486,000 miles per hour, but the energy produced by the train's engine
has nothing to do with that movement. So, it all depends upon what you
are arguing.

>
> you are right, unless, of course, the train is
> standing still on the tracks! ;)

My statement was about "A stone dropped from a moving train". Note the
word "moving."

> Or in my two train example,
> both trains move with the same velocity.
>
> Ed P.

Your experiment was about "2 trains with windows only on the side facing

the other train. Nothing else to reference. Tracks and embankments are

out of sight. Of course also extremely smooth ride, no vibrations to
indicate movement."

What is the purpose of such an experiment? To show that you can create
a situation where no one can tell what is really happening? Everyone
knows that. You can do it by performing an experiment in a closed lab
where you have no way to know if the lab is moving or not.

The point is: If you CAN tell who is moving (by opening the window, for
example) then you can ALSO determine who is moving faster than whom.
You can do it by comparing clock tick rates (if you have identical
clocks). The person whose clock ticks slowest is the person who is
moving fastest.

Ed

[Edward Prochak]

On Monday, July 9, 2018 at 3:11:05 PM UTC-4, Ed Lake wrote:
> [Moderator's note: Huge amount of quoted text deleted. Please quote
> only enough to provide sufficient context. -P.H.]
>
> What I am trying to explain is that time moves slower when an object
> moves faster. And when you reach the speed of light, time stops.
> Period. That is what Einstein's Theory of Special Relativity says.

yes, we agree so far.

>
> The speed of light can be used as a "preferred" reference frame.

That will be hard to do because
the clock on the light beam always reads 0.

>
> When you talk about "frames of reference" where observers are imagined
> to be "stationary," you create a FICTION where each observer sees the
> other observer as moving.

The only way to remove that "FICTION" isd to find an absolute
reference frame. But wait Einstein said there is NO absolute
frame of reference.

>
> Instead, you should do as Einstein recommended and have the observers
> COMPARE the tick rates of their clocks. The clock that is moving the
> fastest will tick at the slowest rate. Thus, instead of fantasizing
> that you are stationary and the other observer is moving, you can
> determine who is ACTUALLY moving faster than whom.

That is the problem, You cannot tell who is "ACTUALLY"
moving. Einstein never made such a statement that it would
tell you who is "ACTUALLY" moving.

>
> The only objects that are "stationary" in our observable universe are
> objects that move at the same speed in the same direction. Their clocks
> will tick at the same rate, so they are "stationary" relative to one
> another, even if both are traveling at 486,000 miles per our around the
> center of the Milky Way galaxy.
>
> Ed

I can agree with the last statement. It's unrelated to the
other points you tried to make.

Do you agree that some of your statements, especially
with the CAPITALIZATION, are describing an absolute
reference frame. Or at the least seem to imply it?

Enjoy,
Ed P.

[Edward Prochak]

On Tuesday, July 10, 2018 at 3:33:02 AM UTC-4, Ed Lake wrote:
> On Monday, July 9, 2018 at 2:13:03 PM UTC-5, Edward Prochak wrote:
> > On Saturday, July 7, 2018 at 9:35:41 PM UTC-4, Ed Lake wrote:

> >> A stone dropped from a moving train cannot drop straight down because
> >> inertia will cause it to move with the train until gravity stops
> >> it. The observation that the stone fell straight down was "incorrect"
> >> because it was inconsistent with the laws of physics. When you
> >> understand how events can APPEAR inconsistent with the laws of
> >> physics while still obeying the laws of physics, then all observers
> >> can agree on what actually happened.
> >>
> >> Ed
> >
> > You still persist in this "correct'/"incorrect" paradigm
> > that begs for a god-like reference frame.
>
> No, it just requires being able to tell the difference between what is
> "real" and what is an "illusion." You may think that the train you are
> on is stationary and the railroad station and embankment outside are
> moving, but that is just an "illusion." If you understand that energy
> was required to make the train move, and the amount of energy used by
> the engine could not possibly make the planet move while the train
> stands still, then you can understand how to tell the difference between
> an "illusion" and reality.

You fail to keep in mind that the train is a star or planet
and the embankment is another star or planet. IOW, you are
making reference to an absolute frame, the planet Earth,
in the above comment.

The point Tom and I are both trying to make is:
there is no illusion!

>
> Of course, it can be argued that it is also an "illusion" that the
> embankment and station are standing still, since both are moving as the
> earth spins on its axis and travels around the center of the galaxy at
> 486,000 miles per hour, but the energy produced by the train's engine
> has nothing to do with that movement. So, it all depends upon what you
> are arguing.

I am arguing that both observations are real.
Both observations are consistent with SR.

>
> >
> > you are right, unless, of course, the train is
> > standing still on the tracks! ;)
>
> My statement was about "A stone dropped from a moving train". Note the
> word "moving."
>
> > Or in my two train example,
> > both trains move with the same velocity.
> >
> > Ed P.
>
> Your experiment was about "2 trains with windows only on the side facing
> the other train. Nothing else to reference. Tracks and embankments are
> out of sight. Of course also extremely smooth ride, no vibrations to
> indicate movement."

yes, or if you prefer, two space trains on an interstellar line

>
> What is the purpose of such an experiment? To show that you can create
> a situation where no one can tell what is really happening? Everyone
> knows that. You can do it by performing an experiment in a closed lab
> where you have no way to know if the lab is moving or not.
>
> The point is: If you CAN tell who is moving (by opening the window, for
> example) then you can ALSO determine who is moving faster than whom.

There is the point:
you can NOT tell who is moving in any absolute manner.
There is no window in this universe to open.

> You can do it by comparing clock tick rates (if you have identical
> clocks). The person whose clock ticks slowest is the person who is
> moving fastest.
>
> Ed

This last point is not clear. You seem to be taking a vote
with multiple observers. So Alice, Bob, and Dan all
agree that Charles has the slowest clock and therefore
is moving fastest of relative to the other three.
That is a valid observation.

But the complimentary conclusion that Charles, Bob,
and Dan all agree that Alice has the fastest clock
does not lead to the conclusion that Alice is not moving.
Alice is still at best only an agreed-to reference frame.

And one more point:
It may be that the others are moving as a group away
from Charles. The observations of the clocks will
be the same. You really cannot know the absolute motion.
And it isn't an illusion.

HTH,
Ed

[Steven Carlip]

On 7/10/18 9:56 PM, Ed Lake wrote:

> On Tuesday, July 10, 2018 at 12:56:33 PM UTC-5, Edward Prochak wrote:
>> On Tuesday, July 10, 2018 at 3:33:02 AM UTC-4, Ed Lake wrote:
>>> On Monday, July 9, 2018 at 2:13:03 PM UTC-5, Edward Prochak wrote:
>>>> On Saturday, July 7, 2018 at 9:35:41 PM UTC-4, Ed Lake wrote:

>>>> You still persist in this "correct'/"incorrect" paradigm
>>>> that begs for a god-like reference frame.

>>> No, it just requires being able to tell the difference between what is
>>> "real" and what is an "illusion." You may think that the train you are
>>> on is stationary and the railroad station and embankment outside are
>>> moving, but that is just an "illusion." If you understand that energy
>>> was required to make the train move, and the amount of energy used by
>>> the engine could not possibly make the planet move while the train
>>> stands still, then you can understand how to tell the difference between
>>> an "illusion" and reality.

It's easy to see that this is wrong.

For simplicity, let's say the tracks are at the equator, running
east to west, and the train has a speed of 100 kph. You want to
say that the train is moving faster than the embankment.

But wait. At the equator, the Earth is rotating at about 1600 kph
from west to east. So the embankment is moving at 1600 kph. If
the train is also moving west to east, its speed is about 1700 kph,
so it's moving faster than the embankment. But if the train is
moving east to west, its speed is about 1500 kph, slower than the
embankment.

But wait. The Earth is also orbiting the Sun at about 100,000 kph.
So the embankment is moving at about 100,000 kph. For about twelve
hours a day, the train will be moving in the same direction as the
Earth's orbit, so it will be going faster than the embankment.
But for the other twelve hours, it will be moving in the opposite
direction as the orbit, so it will be going slower than the embankment.

But wait. The Solar System is also moving, so you'd better account
for that. And the galaxy is moving, and so is the local group of
galaxies,...

Unless you have an absolute reference frame, you have no way to
account for all the velocities to decide what is moving "faster"
than what.

[...]

> Okay, once again: Comparing clock tick rates will show the following:
> Alice is moving slower than Bob. Bob is moving slower than Dan. Dan is
> moving slower than Chuck. Chuck is moving slower than Fred. Fred is
> moving slower than Albert. Albert is moving slower than Henry. Etc.,
> etc., etc, until you get to Louie. Nobody seems to have a clock that
> ticks faster than than Louie's. Is Louie "stationary"? Until you can
> find someone whose clock ticks faster than Louie's, you can measure all
> velocities as relative to Louie. And, if you know Louie's location, you
> can measure all movement as being relative to Louie.

> That is what SR says.

No, that is not what SR says. SR says that in Alice's rest frame, Bob's
clock appears to tick slower than Alice's, and in Bob's rest frame,
Alice's clock appears to tick slower than Bob's. *You* don't get
to decide which clock is "really" slower, unless you want to claim that
your reference frame is better than anyone else's.

Steve Carlip

[Nicolaas Vroom]

On Saturday, 7 July 2018 01:38:32 UTC+2, Tom Roberts wrote:
>
> It OUGHT to be clear that NOTHING we observe can be inconsistent with
> the laws of physics -- we and any physical process we observe are
> necessarily constrained by those laws. I did not "set down a rule" that
> is not already contained in the phrase "laws of physics".

I would like to comment on this in a rather 'open' sense.
First of all identical processes (experiments) have identical descriptions.
Different processes have different descriptions.
Almost identical processes have almost identical descriptions. The
differences in these descriptions we call the parameters of the processes.
That all seems simple but the reality is more complex.
The first problem is we humans. We humans write the descriptions based
on our observations.
Consider a train which travels in a straight line from A to B.
Observer A at A sees the train fading away and becoming smaller.
Observer B at B sees the train awaking at the horizon and becoming larger.
Both tell the truth, but is it the reality? Is the actual train becoming
smaller or larger? No. What you need is one reality, one world, one
reference frame, one coordination system that both observers agree to
use as the basis for all descriptions of all processes.

That means you need some sort of translation of transformation to
transform the observed (measured) reality to this real reality.
In this real reality the process will evolve. At the end you again
need an (inverse) transformation to describe what you actual
will observe (measure).
This recognition between what we observe (which is observer dependent)
and what actual is, is very important, because it is observer independent.
In this real reality the actual processes take place.
One of the best examples is astronomy i.e. the movement of the stars etc.

In this real reality there is also a clear distinction between
processes based on electromagnetic phenomena and gravitational
phenomena. The first are related to radiation and light. The
second are not related to light, only to gravity i.e. gravitons.

However there more. Many processes take place at microscopic level
i.e. at a scale we humans are unable to observe (directly).

Not only that. Our observations are primarily based on light.
This is an issue if the processes we want to understand use light
signals or radiation, which behaviour itself is also a process.
A typical case is a clock.

SNIP

> The absurdity of this is manifest -- EVERYTHING we observe is consistent
> with the laws of physics, there is no possibility of "determining".

This is a tricky issue. All our knowledge evolves by try and error.
It is a struggle.
A typical case is our birds-eye view about the Universe. First we think
it is geocentric then heliocentric and now some think it is a multiverse.

> [Note also that everything we observe is correct (standard
> meaning) -- it simply is not possible to make incorrect
> observations. It is possible to interpret observations
> incorrectly, and when that happens competent scientists
> fix the error.]

Most important is the accuracy of our observations and measurements.
i.e. to make a difference between qualitative and quantitative.
As such the distinction between classical mechanics and quantum mechanics
is vague.

> In fact, science and physics are about modeling the world we inhabit. We
> have learned that the phrase "the laws of physics" is a chimera, and
> today we formulate MODELS, not "laws". For the simple reason that we now
> know that humans can never know the actual Laws used by Nature, the best

> we can possibly do is to approximate them, and that is not at all the sam=
e.

The meaning of chimera is illusion (Webster 1967).
Models, Mathematical equations, Laws are each an approximation of the
physical reality. It is wrong to claim that the world is controlled or
operate accordingly to any law (Newton's Law, SR, GR). Related to chemical=

reactions the laws that describe these reactions enforce certain limitation=
s.
We humans are =E2=80=98controlled' by DNA. These three laws mention=
ed only
describe a small subset of the full physical total.
In many cases starting point should be a model (of a human, a plant,
our economy or life on earth) of what we want to study, in order
to understand how it mechanical or physical (economical) functions
and or operates. The main objective (if possible) is to try to improve
the processes involved.

Above I have mentioned to try to describe the physical processes in
a certain abstract manner, independent of human observations.
Electromagnetic and mechanical processes (the movement of falling objects)=

are clearly different. In that sense I'm also not in favour to try to
unite these processes into one. That does not mean that the mathematics
that describe these processes can not be the (more or less) the same.
When you remove the observation aspects, the underlying mechanical
processes become simpler. Also when all observations are based on
one clock (or a set of synchronised clocks, which its own problems)
you have the same effect.
My philosophy is that mechanical processes don't use photons nor a clock
in order to evolve as they do. For human processes this is different.
Just some =E2=80=98random' thoughts.

Nicolaas Vroom

[Ed Lake]

On Tuesday, July 10, 2018 at 12:56:03 PM UTC-5, Edward Prochak wrote:
> On Monday, July 9, 2018 at 3:11:05 PM UTC-4, Ed Lake wrote:
> > [Moderator's note: Huge amount of quoted text deleted. Please quote
> > only enough to provide sufficient context. -P.H.]

> > The speed of light can be used as a "preferred" reference frame.
>
> That will be hard to do because
> the clock on the light beam always reads 0.

And every other clock in the universe ticks at a faster rate relative
to that zero.

> >
> > When you talk about "frames of reference" where observers are imagined
> > to be "stationary," you create a FICTION where each observer sees the
> > other observer as moving.
>
> The only way to remove that "FICTION" isd to find an absolute
> reference frame. But wait Einstein said there is NO absolute
> frame of reference.

Einstein said NO SUCH THING. He said that the ether was "superfluous,"
which means it is "not necessary." If you use clock tick rates to
measure motion, and clocks stop at the speed of light which is also
the speed limit in the universe, then you do not need the ether.
All motion is relative to the point where time stops.

Personally, I would use the other end of the scale. Instead of
using a moving spot that travels at the speed of light as zero, I
would use a place where clocks tick at their FASTEST rate because
a clock is stationary at that point. All speeds in the universe
would be relative to that point. Where is it? I could tell you,
but it would just generate a new argument. Scientists used Einstein's
equations to determine its existence.

> >
> > Instead, you should do as Einstein recommended and have the observers
> > COMPARE the tick rates of their clocks. The clock that is moving the
> > fastest will tick at the slowest rate. Thus, instead of fantasizing
> > that you are stationary and the other observer is moving, you can
> > determine who is ACTUALLY moving faster than whom.
>
> That is the problem, You cannot tell who is "ACTUALLY"
> moving. Einstein never made such a statement that it would
> tell you who is "ACTUALLY" moving.

That is because, in Einstein's universe, EVERYTHING IS MOVING. So,
the question is not who is actually moving, the only question is:
Who is moving FASTER or SLOWER than whom?

>
> Do you agree that some of your statements, especially
> with the CAPITALIZATION, are describing an absolute
> reference frame. Or at the least seem to imply it?

I have no problem with using a time of zero at the speed of light
and/or an imagined stationary point in space where time ticks at
its fastest rate as an "absolute reference frame." For hundreds
of years mathematicians used an IMAGINARY ETHER as a "preferred
reference frame." Until they find something better, why can't they
use an assumed stationary point in the universe where time ticks
at its fastest rate as a "preferred reference frame"? We KNOW there
is no ether. We do NOT know that there is no stationary point in
the universe. Supposedly the universe sprang from such a point.

Ed

[[Mod. note -- As Tom Roberts (& others) have pointed out, in order
to directly compare clocks A and B, A and B must be colocated for
the duration of the comparison, i.e., they must be at the same
position and (be observed by *all* observers to be) moving at the
same velocity.

If these conditions don't hold, then we can't directly compare A
and B. We may be able to compare (say) A to signals broadcast by
B, but that's a rather different sort of (indirect) comparison.
-- jt]]

[Edward Prochak]

On Wednesday, July 11, 2018 at 8:57:31 PM UTC-4, Nicolaas Vroom wrote:
> On Saturday, 7 July 2018 01:38:32 UTC+2, Tom Roberts wrote:
> >
> > It OUGHT to be clear that NOTHING we observe can be inconsistent with
> > the laws of physics -- we and any physical process we observe are
> > necessarily constrained by those laws. I did not "set down a rule" that
> > is not already contained in the phrase "laws of physics".
>
> I would like to comment on this in a rather 'open' sense.
> First of all identical processes (experiments) have identical descriptions.
> Different processes have different descriptions.
> Almost identical processes have almost identical descriptions. The
> differences in these descriptions we call the parameters of the processes.
> That all seems simple but the reality is more complex.
> The first problem is we humans. We humans write the descriptions based
> on our observations.

> Nicolaas Vroom

Very nice commentary. I cut it short
because I have a short and simple comment.

Of course the first variation of this that I learned
is in the form of two of Murphy's laws

Mother nature sides with the hidden flaw.
and
Mother nature is a b!^(#

I have heard other variations on this idea,
but a good friend of mine sums it up this way:

All theories are wrong. Some are useful.

Keeping that idea in mind has hopefully helped me
be humble in some of these discussions. I don't
have the ANSWER. I don't KNOW the TRUTH. I can
only accept the best information and best interpretation
available.


Ed P

[[Mod. note -- Another variant on this idea is:
The Three Laws of Thermodynamics:
1) You can't win, only lose or break even.
2) You can only break even at absolute zero.
3) You can't get to absolute zero.
-- jt]]

[Edward Prochak]

On Wednesday, July 11, 2018 at 9:31:48 PM UTC-4, Ed Lake wrote:
> On Tuesday, July 10, 2018 at 12:56:03 PM UTC-5, Edward Prochak wrote:
> > On Monday, July 9, 2018 at 3:11:05 PM UTC-4, Ed Lake wrote:
> > > [Moderator's note: Huge amount of quoted text deleted. Please quote
> > > only enough to provide sufficient context. -P.H.]
>
> > > The speed of light can be used as a "preferred" reference frame.
> >
> > That will be hard to do because
> > the clock on the light beam always reads 0.
>
> And every other clock in the universe ticks at a faster rate relative
> to that zero.
>
> > >
> > > When you talk about "frames of reference" where observers are imagined
> > > to be "stationary," you create a FICTION where each observer sees the
> > > other observer as moving.
> >
> > The only way to remove that "FICTION" isd to find an absolute
> > reference frame. But wait Einstein said there is NO absolute
> > frame of reference.
>
> Einstein said NO SUCH THING. He said that the ether was "superfluous,"
> which means it is "not necessary." If you use clock tick rates to
> measure motion, and clocks stop at the speed of light which is also
> the speed limit in the universe, then you do not need the ether.

yes, but this statement:

> All motion is relative to the point where time stops.

is nonsense. You cannot calculate relative to that clock
because you end up calculating 0/0. NAN

>
> Personally, I would use the other end of the scale. Instead of
> using a moving spot that travels at the speed of light as zero, I
> would use a place where clocks tick at their FASTEST rate because
> a clock is stationary at that point. All speeds in the universe
> would be relative to that point. Where is it? I could tell you,
> but it would just generate a new argument. Scientists used Einstein's
> equations to determine its existence.

But there is no such clock (reference frame).
If you have some mystical revelation providing this,
please share.

>
> > >
> > > Instead, you should do as Einstein recommended and have the observers
> > > COMPARE the tick rates of their clocks. The clock that is moving the
> > > fastest will tick at the slowest rate. Thus, instead of fantasizing
> > > that you are stationary and the other observer is moving, you can
> > > determine who is ACTUALLY moving faster than whom.
> >
> > That is the problem, You cannot tell who is "ACTUALLY"
> > moving. Einstein never made such a statement that it would
> > tell you who is "ACTUALLY" moving.
>
> That is because, in Einstein's universe, EVERYTHING IS MOVING. So,
> the question is not who is actually moving, the only question is:
> Who is moving FASTER or SLOWER than whom?
>

You are still grasping for an absolute frame. Einstein did not
say everything is moving. (If you have a quote, you can correct me)
He said motion is measured relative to a frame of reference.

> >
> > Do you agree that some of your statements, especially
> > with the CAPITALIZATION, are describing an absolute
> > reference frame. Or at the least seem to imply it?
>
> I have no problem with using a time of zero at the speed of light
> and/or an imagined stationary point in space where time ticks at
> its fastest rate as an "absolute reference frame."

We can imagine such a point, but I honestly see no way
to locate it except as the place where I sit right now

> For hundreds
> of years mathematicians used an IMAGINARY ETHER as a "preferred
> reference frame."

Well philosophers, not mathematicians, discussed
the idea and it started about 2 millenia ago.

> Until they find something better, why can't they
> use an assumed stationary point in the universe where time ticks
> at its fastest rate as a "preferred reference frame"? We KNOW there
> is no ether. We do NOT know that there is no stationary point in
> the universe. Supposedly the universe sprang from such a point.
>
> Ed

Even if the universe began as a point-like location,
it now has no definable/observable center point.

>
> [[Mod. note -- As Tom Roberts (& others) have pointed out, in order
> to directly compare clocks A and B, A and B must be colocated for
> the duration of the comparison, i.e., they must be at the same
> position and (be observed by *all* observers to be) moving at the
> same velocity.
>
> If these conditions don't hold, then we can't directly compare A
> and B. We may be able to compare (say) A to signals broadcast by
> B, but that's a rather different sort of (indirect) comparison.
> -- jt]]

Thank you, jt.

Ed P.

[Ed Lake]

On Wednesday, July 11, 2018 at 8:31:48 PM UTC-5, Ed Lake wrote:
> On Tuesday, July 10, 2018 at 12:56:03 PM UTC-5, Edward Prochak wrote:
> > On Monday, July 9, 2018 at 3:11:05 PM UTC-4, Ed Lake wrote:
> > > [Moderator's note: Huge amount of quoted text deleted. Please quote
> > > only enough to provide sufficient context. -P.H.]

< snip >

> [[Mod. note -- As Tom Roberts (& others) have pointed out, in order
> to directly compare clocks A and B, A and B must be colocated for
> the duration of the comparison, i.e., they must be at the same
> position and (be observed by *all* observers to be) moving at the
> same velocity.
>
> If these conditions don't hold, then we can't directly compare A
> and B. We may be able to compare (say) A to signals broadcast by
> B, but that's a rather different sort of (indirect) comparison.
> -- jt]]

Sorry, Moderator, but I can make no sense of your post. It seems
to require having the same observers in two different places at
once.

The problem is to compare a moving clock to a clock that is considered
"stationary" (or moving at a slower rate). According to Einstein,
that is done by first placing clocks A and B side by side to make
certain they are identical and synchronized. Then clock B is moved
away and brought back. Due to its movement, the time shown by clock
B should then "lag behind" the time shown by clock A. I.e., clock
B ran at a slower rate WHILE moving.

How can you compare a moving clock (B) to a "stationary" clock (A)
if "A and B must be colocated for the duration of the comparison"?

[[Mod. note -- My apologies for an overly-simplified and (in hindsight)
insufficiently clear explanation.

My point was that such a comparison necessarily requires either
(i) some way to transmit B's time readings to A (or A's to B) while
the two clocks are in different locations -- in this case the
comparison is somewhat indirect, and we need to take the
time transmission into account in the comparison; and/or
(ii) waiting until B returns to A to compare their readings
(which doesn't give us any information about when/where
any difference in readings originated).

If you can get a copy of it (alas I think it's paywalled), the article

https://link.springer.com/chapter/10.1007/978-1-4613-3712-6_18
Carroll O. Alley,
"Proper time experiments in gravitational fields with
atomic clocks, aircraft, and laser light pulses",
pages 363--427 in
Pierre Meystre and Marian O. Scully,
"Quantum Optics, Experimental Gravitation, and Measurement Theory",
Proceedings of the NATO Advanced Study Institute on Quantum Optics
and Experimental General Relativity,
held August 1981 in Bad Windsheim, Germany
NATO Science Series: B, vol. 94, (Plenum Press, New York, 1983)
ISBN 978-1-4613-3714-0
is a fascinating account of doing just such experiments (with atomic
clocks flown in airplanes), using real-time laser signals exchanged
between a ground station and the airplane to implement (i). The
authors' results (see especially figures 44-49) are in complete
agreement with special & general relativity (and clearly show both
special- and general-relativity effects).
-- jt]]

On the other hand, it all depends upon what you mean by "colocated."
In a new paper I just wrote (titled "Analyzing the 'Twin Paradox'")
I suggest an experiment using a large centrifuge like the one at
NASA's Ames Research Center. You could perform an experiment similar
to the 1971 Hafele-Keating experiment by putting 4 atomic clocks
on the centrifuge while placing an identical clock in the control
room outside of the the centrifuge room. The spinning/moving
centrifuge can create 20Gs of gravity for the clocks for about 22
hours. Then, you can compare the time on the clocks that were in
the centrifuge to the control room clock to see how much time was
lost by the clocks that moved. Time should be slowed during the
movement AND by the added acceleration/gravity.

Here's the link to my new paper: http://vixra.org/pdf/1807.0192v1.pdf

Ed

[[Mod. note -- Your proposed experiment sounds a lot like
Hay et al,
"Measurement of the Red Shift in an Accelerated System
using the Moessbauer Effect in Fe^57"
Physical Review Letters volume 4, number 4, Feb 15 1960,
pages 165-166
https://doi.org/10.1103/PhysRevLett.4.165
They found results consistent with special relativity.
-- jt]]

[Phillip Helbig (undress to reply)]

> [[Mod. note -- My apologies for an overly-simplified and (in hindsight)
> insufficiently clear explanation.

I can't resist pointing out that Einstein himself said that everything
should be made as simple as possible, but not simpler. :-)

[Phillip Helbig (undress to reply)]

In article <a2e4c81e-31d0-47f8...@googlegroups.com>,
Edward Prochak <edpr...@gmail.com> writes:=20

> [[Mod. note -- Another variant on this idea is:
> The Three Laws of Thermodynamics:
> 1) You can't win, only lose or break even.
> 2) You can only break even at absolute zero.
> 3) You can't get to absolute zero.
> -- jt]]

The "real" laws are:
1) Energy is conserved
2) Entropy increases
3) Absolute zero cannot be reached

Another variant is:
1) You can't win
2) You can't break even
3) You can't even get out of the game

[mr...@ing.puc.cl]

The moving clock is assumed to be moving at a very high speed (in order to
time dilation effects to be observed). So if clock A is moving at speed 0.6c
in order to measure the time dilation you need a set of Einstein synchronized
clocks located along the path clock A is following.

This is the only way to check the readings of clock A with the readings of the
synchronized clocks, so the clock A reading is directly compared with a given
synchronized clock B, as clock A passes through clock B location (at that
instant both clocks are colocated).

Afterwards, the lectures of the synchronized clocks can be compared to determine
the time dilation of clock A. The following diagram shows the setup.

Clock A

(*) --> v=0.6c

(B1)....(B2)....(B3)....(B4)....(B5)....(B6)

Synchronized clocks

[Ed Lake]

On Friday, July 13, 2018 at 12:11:10 AM UTC-5, Edward Prochak wrote:
> On Wednesday, July 11, 2018 at 9:31:48 PM UTC-4, Ed Lake wrote:
>> On Tuesday, July 10, 2018 at 12:56:03 PM UTC-5, Edward Prochak wrote:
>>> On Monday, July 9, 2018 at 3:11:05 PM UTC-4, Ed Lake wrote:

< snip >

>>>> Instead, you should do as Einstein recommended and have the observers
>>>> COMPARE the tick rates of their clocks. The clock that is moving the
>>>> fastest will tick at the slowest rate. Thus, instead of fantasizing
>>>> that you are stationary and the other observer is moving, you can
>>>> determine who is ACTUALLY moving faster than whom.
>>>
>>> That is the problem, You cannot tell who is "ACTUALLY"
>>> moving. Einstein never made such a statement that it would
>>> tell you who is "ACTUALLY" moving.
>>
>> That is because, in Einstein's universe, EVERYTHING IS MOVING. So,
>> the question is not who is actually moving, the only question is:
>> Who is moving FASTER or SLOWER than whom?
>>
> You are still grasping for an absolute frame. Einstein did not
> say everything is moving. (If you have a quote, you can correct me)
> He said motion is measured relative to a frame of reference.

Yes, "motion is measured relative to a frame of reference" whether the
frame of reference is moving or not. Einstein didn't "say" everything
is moving, he ASSUMED everything is moving.

Einstein defines a "stationary system" as one where light travels from A
to B in the same time it travels from B to A. He states on page 3 of
his 1905 paper:

"It is essential to have time defined by means of stationary clocks in the
stationary system, and the time now defined being appropriate to the stationary
system we call it 'the time of the stationary system.'"

That "stationary system" can be traveling at any speed. It is not truly
"stationary." It is a "stationary system," which only means its points
are stationary relative to one another.

Then at the bottom of page 10 Einstein says,

"If at the points A and B of K there are stationary clocks which, viewed
in the stationary system, are synchronous; and if the clock at A is
moved with the velocity v along the line AB to B, then on its arrival at
B the two clocks no longer synchronize, but the clock moved from A to B
lags behind the other which has remained at B."

So, in this "stationary system" (which can be moving at any speed slower
than the speed of light), if a clock moves parallel to the movement of
the system, that clock will show that it ran slower while moving.

In other words, you can determine who moves WITHIN a "stationary system" by whose clock slowed down.

And you can tell which "stationary system" is moving faster or slower
than the other by comparing clock tick rates. The system where clocks
tick slowest is the system which is moving fastest.

< snip >

> Even if the universe began as a point-like location,
> it now has no definable/observable center point.

True, it is not observable because it is not in the "observable
universe," where the lights didn't turn on until millions of years after
the Big Bang.

BUT, if you can tell who is moving faster than whom, and if you cannot
move faster than the speed of light, then there MUST be a point where
things would be truly stationary. It would be the point where time
ticks at its fastest rate.

Ed

[Ed Lake]

On Friday, July 13, 2018 at 12:33:23 AM UTC-5, Ed Lake wrote:
> On Wednesday, July 11, 2018 at 8:31:48 PM UTC-5, Ed Lake wrote:
> > On Tuesday, July 10, 2018 at 12:56:03 PM UTC-5, Edward Prochak wrote:
> > > On Monday, July 9, 2018 at 3:11:05 PM UTC-4, Ed Lake wrote:

> > > > [Moderator's note: Huge amount of quoted text deleted. Please quo=

Okay, no one is suggesting option (i). And, I do not understand your conce=
rn about option (ii). According to Einstein (and experiments) clocks slow =
down while moving, so the difference in readings originated while the clock=
s were moving. Hafele and Keating flew along with their four atomic clocks=
which showed that the differences between their clocks and the "control" c=
lock at the U.S. Naval Observatory occurred while flying. Where or when el=
se would the differences occur or originate?

< snip >

> In a new paper I just wrote (titled "Analyzing the 'Twin Paradox'")
> I suggest an experiment using a large centrifuge like the one at
> NASA's Ames Research Center. You could perform an experiment similar
> to the 1971 Hafele-Keating experiment by putting 4 atomic clocks
> on the centrifuge while placing an identical clock in the control
> room outside of the the centrifuge room. The spinning/moving
> centrifuge can create 20Gs of gravity for the clocks for about 22
> hours. Then, you can compare the time on the clocks that were in
> the centrifuge to the control room clock to see how much time was
> lost by the clocks that moved. Time should be slowed during the
> movement AND by the added acceleration/gravity.
>
> Here's the link to my new paper: http://vixra.org/pdf/1807.0192v1.pdf
>
> Ed
>
> [[Mod. note -- Your proposed experiment sounds a lot like
> Hay et al,
> "Measurement of the Red Shift in an Accelerated System
> using the Moessbauer Effect in Fe^57"
> Physical Review Letters volume 4, number 4, Feb 15 1960,
> pages 165-166
> https://doi.org/10.1103/PhysRevLett.4.165
> They found results consistent with special relativity.
> -- jt]]

Except my proposed experiment is VASTLY simpler. It all takes place
inside a single building, and there are no transmitted signals to
confuse the situation. Plus, if you want to know when and where
the time differences occurred, they could ONLY have occurred while
the centrifuge was spinning. If you think they could have occurred
at some other time, tests can probably be devised to confirm or
disprove your ideas.

Ed

[[Mod. note --
Option (i) above [transmitting B's time readings to A while they
are in different locations] is precisely what is described in the
book chapter by Carroll Alley which I cited.

The Hay et al experiment took place on a single tabletop, comparing
clocks (Fe^57 nuclei) on the rim versus on the rotational axis of an
ultracentrifuge.
-- jt]]

[Phillip Helbig (undress to reply)]

In article <68934763-d472-4842...@googlegroups.com>, Ed

Lake <det...@newsguy.com> writes:

> BUT, if you can tell who is moving faster than whom, and if you cannot
> move faster than the speed of light, then there MUST be a point where

> things would be truly stationary. It would be the point where time
> ticks at its fastest rate.

Not within the context of special relativity. Any observer can regard
himself as at rest and measure all motion relative to him. That's why
it's called the theory of relativity. In special relativity, the only
meaningful velocity is a relative velocity. There is no preferred
frame, no observer can be deemed objectively to be at rest.

[Tom Roberts]

On 7/11/18 7:57 PM, Nicolaas Vroom wrote:
> On Saturday, 7 July 2018 01:38:32 UTC+2, Tom Roberts wrote:
>> It OUGHT to be clear that NOTHING we observe can be inconsistent
>> with the laws of physics -- we and any physical process we observe
>> are necessarily constrained by those laws. I did not "set down a
>> rule" that is not already contained in the phrase "laws of
>> physics".
>

> First of all identical processes (experiments) have identical
> descriptions.

Not true. In the example discussed in this thread, the train observer
describes it as "the stone falls straight down", while the embankment
observer describes it as "the stone falls in a parabolic arc". These are
different descriptions of a single process, due to the observers'
different perspectives.

You yourself give another counterexample to this claim:

> Consider a train which travels in a straight line from A to B.
> Observer A at A sees the train fading away and becoming smaller.
> Observer B at B sees the train awaking at the horizon and becoming
> larger.

That's two different descriptions of a single phenomenon. They differ
because they are descriptions from different perspectives.

> Both tell the truth, but is it the reality? Is the actual train
> becoming smaller or larger? No. What you need is one reality, one
> world, one reference frame, one coordination system that both
> observers agree to use as the basis for all descriptions of all
> processes.

There is one "reality", one world. But trying to single out "one
reference frame, one coordinate system" is USELESS -- all are equally
valid; they give different descriptions of phenomena based on their
different perspectives. We do this ALL THE TIME, and I don't see why you
have difficulty with it. Note you CANNOT separate an observer from her
perspective; for many cases in physics, "perspective" means "coordinates".

> That means you need some sort of translation of transformation to
> transform the observed (measured) reality to this real reality.

"Real reality" is a hopeless obfuscation. Henceforth I substitute
"world" for your "real reality", as that is the usual word for what you
mean. ("World" as distinguished from "model"; more on this below.)

You cannot avoid the fact that different perspectives of a given
phenomenon will yield different descriptions of it. Ditto for
"perspective" => "coordinates".

Note that no physical phenomenon can possibly depend on an observer's
perspective or coordinates (nature uses neither), so the physical laws
that describe the phenomenon must be independent of both.

"Physical laws" is an ambiguous phrase: it can mean the
unknown methods by which nature behaves in the world,
or it can mean the human statements of general models
derived from observations of how nature behaves. But
in order for the latter to accurately reproduce the
former, they must be independent of perspective and
coordinates (for both meanings of "they").

> This recognition between what we observe (which is observer
> dependent) and what actual is, is very important, because it is
> observer independent.

Yes. But every description requires a perspective (coordinates).

> In [the world] the actual processes take place.

Yes. Physical processes take place in the world; we humans describe them
using a MODEL, and such descriptions inherently require a
perspective/coordinates, because that is how we formulate models.

Every word we use is not reality, not the world, it is
a thought; those that relate to the world are MODELS.

One must, of course, distinguish between world and model. This can be
cumbersome as our language consists of relating thoughts to each
other, and is necessarily bound to models of the world.

Models are how we humans survive in the world. You cannot find your bed
at night without a model of your domicile: you mentally traverse the
model from your current location to your bed, and then manipulate your
body to follow that path.

> In [the world] there is also a clear distinction between processes

> based on electromagnetic phenomena and gravitational phenomena.

Nonsense. It is our MODELS that distinguish this. Nature just does
whatever she does (which we do not "know", we only model). We have
CHOSEN to use different models for gravitation and electrodynamics.

There is, of course, much effort being expended in the
search for a "theory of everything", which would
presumably erase this artificial distinction between
these models, and unify their disjoint domains.

> [...]

Tom Roberts

[Ed Lake]

On Friday, July 13, 2018 at 4:45:15 PM UTC-5, mr...@ing.puc.cl wrote:
> El viernes, 13 de julio de 2018, 0:33:23 (UTC-5), Ed Lake escribió:
>> On Wednesday, July 11, 2018 at 8:31:48 PM UTC-5, Ed Lake wrote:
>>> On Tuesday, July 10, 2018 at 12:56:03 PM UTC-5, Edward Prochak wrote:
>>>> On Monday, July 9, 2018 at 3:11:05 PM UTC-4, Ed Lake wrote:
>>>>> [Moderator's note: Huge amount of quoted text deleted. Please quote
>>>>> only enough to provide sufficient context. -P.H.]
>>
>> < snip >
>>
>>> [[Mod. note -- As Tom Roberts (& others) have pointed out, in order
>>> to directly compare clocks A and B, A and B must be colocated for
>>> the duration of the comparison, i.e., they must be at the same
>>> position and (be observed by *all* observers to be) moving at the
>>> same velocity.

>> How can you compare a moving clock (B) to a "stationary" clock (A)
>> if "A and B must be colocated for the duration of the comparison"?
>>
>
> The moving clock is assumed to be moving at a very high speed (in order to
> time dilation effects to be observed). So if clock A is moving at speed 0.6c
> in order to measure the time dilation you need a set of Einstein synchronized
> clocks located along the path clock A is following.
>
> This is the only way to check the readings of clock A with the readings of the
> synchronized clocks, so the clock A reading is directly compared with a given
> synchronized clock B, as clock A passes through clock B location (at that
> instant both clocks are colocated).
>
> Afterwards, the lectures of the synchronized clocks can be compared to determine
> the time dilation of clock A. The following diagram shows the setup.
>
> Clock A
>
> (*) --> v=0.6c
>
> (B1)....(B2)....(B3)....(B4)....(B5)....(B6)
>
> Synchronized clocks

Sorry, but your beliefs conflict with reality. In 1971, Joseph Hafele
and Richard Keating performed a test where they flew 4 atomic clocks
around the world twice, first flying them eastward, then westward.
Before each trip they compared the clocks to a master atomic clock at
the US Naval observatory.

Before making the trips, they calculated what the results should be
(using both gravitational time dilation and velocity (kinematic) time
dilation). After completing the trips they matched actual results to
the predicted results and they were within the margin of error.

Since then, others have performed similar experiments and got similar
results. They did NOT travel faster than commercial airliner speeds,
and they did NOT need any synchronized clocks positioned along the way.

Sources: https://en.wikipedia.org/wiki/Hafele%E2%80%93Keating_experiment
http://hyperphysics.phy-astr.gsu.edu/hbase/Relativ/airtim.html

Ed

[mr...@ing.puc.cl]

Firstly, these are not my beliefs but facts of the SR model. Secondly, your
description of what Hafele and Keating did is correct.
But you have to understand that the comparison among clocks were performed
AFTER the experiment. The atomic clocks were flown around the world, as you say
but, obviously, they could not compare their clock readings with the readings
of the master atomic clock while they were flying (since the clocks were not
colocated).

And finally, what the comparison was about related to the ELAPSED time of the
different clocks. The elapsed time of a clock is not the tick rate of that clock.

[Ed Lake]

You cannot compare clock tick rates while one is clock is moving at one
speed and the other clock is moving at a significantly different speed.
So, you have to COMPUTE how much slower one ticked than the other based
upon the difference in the elapsed times shown by the two clocks at the
end of the experiment.

Or do you think the clocks ticked at the same rates during the test and
somehow magically adjusted themselves at the end of the experiment in
order to fool the experimenters?

Ed

[Steven Carlip]

On 7/11/18 6:31 PM, Ed Lake wrote:

[...]

> Personally, I would use the other end of the scale. Instead of using
> a moving spot that travels at the speed of light as zero, I would use
> a place where clocks tick at their FASTEST rate because a clock is
> stationary at that point.

I'm sorry, but I don't understand. Who gets to decide which clock
is fastest?

Suppose Alice and Bob are in trains moving in opposite directions.
In Alice's rest frame, her clock is "faster", and Bob's is "slower."
In Bob's rest frame, his clock is "faster," and hers is slower.
Which one gets to decide?

> All speeds in the universe would be

> relative to that point.Where is it? I could tell you, but it would

> just generate a new argument. Scientists used Einstein's equations
> to determine its existence.

No, we don't. Really.

Steve Carlip

[mr...@ing.puc.cl]

El domingo, 15 de julio de 2018, 3:47:37 (UTC-5), Ed Lake escribió:
> On Saturday, July 14, 2018 at 11:40:18 AM UTC-5, mr...@ing.puc.cl wrote:

> > Firstly, these are not my beliefs but facts of the SR model. Secondly, your
> > description of what Hafele and Keating did is correct.
> > But you have to understand that the comparison among clocks were performed
> > AFTER the experiment. The atomic clocks were flown around the world, as you say
> > but, obviously, they could not compare their clock readings with the readings
> > of the master atomic clock while they were flying (since the clocks were not
> > colocated).
> >
> > And finally, what the comparison was about related to the ELAPSED time of the
> > different clocks. The elapsed time of a clock is not the tick rate of that clock.
>
> You cannot compare clock tick rates while one is clock is moving at one
> speed and the other clock is moving at a significantly different speed.

That is what you have been told by Tom, me and others. You need to have those
clocks colocated to compare either the elapsed time or the tick rate.

However, you could perform the comparison while the clock is moving. The only
way to do that comparison, is to locate synchronized clocks along the trajectory of the
relatively moving clock, so that comparisons are made between temporary
colocated clocks, as shown in the diagram I presented to you before.

> So, you have to COMPUTE how much slower one ticked than the other based
> upon the difference in the elapsed times shown by the two clocks at the
> end of the experiment.
>

It is much more simpler than that: when the clocks are reunited, and so
they are colocated, you just can SEE this clock lags or leads the other
clock. Note that while the clock readings are different, the clocks
continue to tick at 1 sec/sec.

> Or do you think the clocks ticked at the same rates during the test and
> somehow magically adjusted themselves at the end of the experiment in
> order to fool the experimenters?
>
> Ed

The physics of the processes that make a Caesium atomic clock to work
are not changed when that clock moves. This should be evident to you,
assuming that you have travelled inside an airplane. When you take a cup
of coffee inside an airplane, you do it the same way you take a cup of
coffee at your kitchen, right?

That means that the "laws of physics" are the same inside an airplane as
they are at your kitchen.

So you tell us what physical law makes an atomic clock inside an
airplane to tick slow, compared with a ground clock?

The real explanation of the difference on the clock readings, is found
in the differences on the trajectories the flown clock and the ground
clock followed.

[Nicolaas Vroom]

On Friday, 13 July 2018 07:33:23 UTC+2, Ed Lake wrote:

> > [[Mod. note -- As Tom Roberts (& others) have pointed out, in order
> > to directly compare clocks A and B, A and B must be colocated for
> > the duration of the comparison, i.e., they must be at the same
> > position and (be observed by *all* observers to be) moving at the
> > same velocity.
> >
> > If these conditions don't hold, then we can't directly compare A
> > and B. We may be able to compare (say) A to signals broadcast by
> > B, but that's a rather different sort of (indirect) comparison.
> > -- jt]]

> How can you compare a moving clock (B) to a "stationary" clock (A)
> if "A and B must be colocated for the duration of the comparison"?
>
> [[Mod. note -- My apologies for an overly-simplified and (in hindsight)
> insufficiently clear explanation.
>
> My point was that such a comparison necessarily requires either
> (i) some way to transmit B's time readings to A (or A's to B) while
> the two clocks are in different locations -- in this case the
> comparison is somewhat indirect, and we need to take the
> time transmission into account in the comparison; and/or
> (ii) waiting until B returns to A to compare their readings
> (which doesn't give us any information about when/where
> any difference in readings originated).

IMO starting point should be a simple experiment using the clock
as described in the book "SpaceTime Physics" i.e. a flashing
light between two mirrors.
That means you have a clock A which stays at home at P1 and a clock B
which travels in a straight line (constant speed) to a point P2
and back to P1 and compare readings (i.e. item ii).
In case the mirrors of B's clock are perpendicular to the direction
of movement and A's clock shows 8 counts than B's clock will show 6
counts with v = 0.5*c
For more details see my homepage:
http://users.telenet.be/nicvroom/Book_Review_Spacetime_Physics.htm#ref3

In case the mirrors of B's clock are parallel to the direction
of movement and A's clock shows 8 counts than B's clock will show 4*sqr(3)
counts with v = 0.5*c
This is in agreement with SR i.e. Lorentz transformation.
For more details see my homepage:
http://users.telenet.be/nicvroom/Book_Review_Spacetime_Physics.htm#ref4

Item (i) discusses clocks at different locations.
This issue is discussed at:
http://users.telenet.be/nicvroom/Book_Review_Spacetime_Physics.htm#ref7
i.e. explanation of the twin paradox.
This section also discusses when and where any difference in readings
originate.
In fact this happens where there is any change in speed i.e.
in some sense always (except if the clock is completely stabilized)

Nicolaas Vroom

[Ed Lake]

On Saturday, July 14, 2018 at 11:40:18 AM UTC-5, mr...@ing.puc.cl wrote:

> El s=C3=A1bado, 14 de julio de 2018, 11:17:42 (UTC-5), Ed Lake escribi=C3=B3:

> > On Friday, July 13, 2018 at 4:45:15 PM UTC-5, mr...@ing.puc.cl wrote:

> >> El viernes, 13 de julio de 2018, 0:33:23 (UTC-5), Ed Lake escribi=C3=B3:

If the clocks tick at the same rate and show the same time at the
start of the experiment but showed different elapsed times after
the experiment, then the difference in elapsed times indicates a
difference in tick rates. If the clock that moved shows an elapsed
time that is 24 nanoseconds less than the "stationary" clock after
24 hours, then the clock that moved ticked at a rate that was 1
nanosecond per hour slower than the clock that was stationary.

Ed

[Torn Rumero DeBrak]

Am 15.07.2018 um 10:47 schrieb Ed Lake:
> On Saturday, July 14, 2018 at 11:40:18 AM UTC-5, mr...@ing.puc.cl wrote:

>> El s=C3=A1bado, 14 de julio de 2018, 11:17:42 (UTC-5), Ed Lake escribi=C3=B3:

>>> On Friday, July 13, 2018 at 4:45:15 PM UTC-5, mr...@ing.puc.cl wrote:

>>>> El viernes, 13 de julio de 2018, 0:33:23 (UTC-5), Ed Lake escribi=C3=B3:

No, you have to COMPARE and MEASURE. That's physics. COMPUTE is
Mathematics, which should reflect the measurements.
Without input from measurements of the nature, you cannot create
a valid mathematical theory of nature. The the theory comes after
observations, as nature is not ruled by mathematical laws.

> Or do you think the clocks ticked at the same rates during the test and
> somehow magically adjusted themselves at the end of the experiment in
> order to fool the experimenters?
>

The clock ticks with the same rate at the beginning, during and at the
end of the experiment (measured by the clock). There is no other
alternative.

Aloha

[Edward Prochak]

On Friday, July 13, 2018 at 5:45:17 PM UTC-4, Ed Lake wrote:
> On Friday, July 13, 2018 at 12:11:10 AM UTC-5, Edward Prochak wrote:
> > On Wednesday, July 11, 2018 at 9:31:48 PM UTC-4, Ed Lake wrote:

< snip >

> >> That is because, in Einstein's universe, EVERYTHING IS MOVING. So,
> >> the question is not who is actually moving, the only question is:
> >> Who is moving FASTER or SLOWER than whom?
> >>
> > You are still grasping for an absolute frame. Einstein did not
> > say everything is moving. (If you have a quote, you can correct me)
> > He said motion is measured relative to a frame of reference.
>
> Yes, "motion is measured relative to a frame of reference" whether the
> frame of reference is moving or not. Einstein didn't "say" everything
> is moving, he ASSUMED everything is moving.

Now you are just making your own assumption!

>
> Einstein defines a "stationary system" as one where light travels from A
> to B in the same time it travels from B to A. He states on page 3 of
> his 1905 paper:
>
> "It is essential to have time defined by means of stationary clocks in the
> stationary system, and the time now defined being appropriate to the stationary
> system we call it 'the time of the stationary system.'"
>
> That "stationary system" can be traveling at any speed. It is not truly
> "stationary." It is a "stationary system," which only means its points
> are stationary relative to one another.

<snip>

> So, in this "stationary system" (which can be moving at any speed slower
> than the speed of light), if a clock moves parallel to the movement of
> the system, that clock will show that it ran slower while moving.

So far so good.

>
> In other words, you can determine who moves
> WITHIN a "stationary system" by whose clock slowed down.

Except in the "stationary system" the observer assigns
his own speed as zero, as appropriate for a "stationary system".

>
> And you can tell which "stationary system" is moving faster or slower
> than the other by comparing clock tick rates. The system where clocks
> tick slowest is the system which is moving fastest.

We have gone over this.

>
> < snip >
>
> > Even if the universe began as a point-like location,
> > it now has no definable/observable center point.
>
> True, it is not observable because it is not in the "observable
> universe," where the lights didn't turn on until millions of years after
> the Big Bang.

Just an excuse. You need to demonstrate a method for finding that
one unique center point. Here you present part of it:

>
> BUT, if you can tell who is moving faster than whom, and if you cannot
> move faster than the speed of light, then there MUST be a point where
> things would be truly stationary. It would be the point where time
> ticks at its fastest rate.
>
> Ed

But that still does not give you a stationary reference point.

proof by counterexample:
The universe has systems A and B
A moves left away from B
B moves right away from A
Which clock ticks fastest?
Which system is the "center point" that is not moving?

Ed

[mr...@ing.puc.cl]

That is, again, your assertion and you have not provided any proof of that.
You may think your assertion is logical, but physics is not based in logic
but in building models and test them by experiments.

The different elapsed times are due to the geometry of the movements of the
clocks. They follow different paths, which each clock travels at exactly
1 sec/sec. Since the paths are different, it follows that the amount of time
between the start and the end of the experiment will indeed differ.

Again, this is quite similar to why two identical odometers, in two identical
cars, show different distances between Chicago and New York, because they
followed different paths between these two cities. The difference is due to the
geometry of the problem.

You recognize that you are not interested in going into the equations that
show this geometry, because you are not familiar with any math regarding this
problem. Proceeding in that way, it will get too difficult to you to understand
any of the basics of Special or General Relativity.

[Nicolaas Vroom]

On Saturday, 14 July 2018 18:17:41 UTC+2, Tom Roberts wrote:
> On 7/11/18 7:57 PM, Nicolaas Vroom wrote:
> > First of all identical processes (experiments) have identical
> > descriptions.
>
> Not true.

The idea is when we try to perform the same experiment the descriptions
and the results should be the same. (repeatability)
You can ofcourse only do that when you remove everything what is
observer dependent. The description (model) should be observer independent.
My observations are subjectif. The descriptions should be objectif.

> In the example discussed in this thread, the train observer
> describes it as "the stone falls straight down", while the embankment
> observer describes it as "the stone falls in a parabolic arc". These are
> different descriptions of a single process, due to the observers'
> different perspectives.

Correct. They are subjectif (If that is the correct defintion)

> You yourself give another counterexample to this claim:
>
> > Consider a train which travels in a straight line from A to B.
> > Observer A at A sees the train fading away and becoming smaller.
> > Observer B at B sees the train awaking at the horizon and becoming
> > larger.
>
> That's two different descriptions of a single phenomenon. They differ
> because they are descriptions from different perspectives.

Correct. But the real description should be observer independent.
This requires a certain transformation to come to one common
description. An objectif description.

> There is one "reality", one world. But trying to single out "one
> reference frame, one coordinate system" is USELESS -- all are equally
> valid; they give different descriptions of phenomena based on their
> different perspectives. We do this ALL THE TIME, and I don't see why you
> have difficulty with it. Note you CANNOT separate an observer from her
> perspective; for many cases in physics, "perspective" means "coordinates".

If you want to predict the position of the stars you also use one
reference frame and one clock (Time keeping system)

> You cannot avoid the fact that different perspectives of a given
> phenomenon will yield different descriptions of it. Ditto for
> "perspective" => "coordinates".

A given phenomenon can give different observations.

> Note that no physical phenomenon can possibly depend on an observer's
> perspective or coordinates (nature uses neither), so the physical laws
> that describe the phenomenon must be independent of both.

Correct. But for me physical laws are equivalent to descriptions.
A different name is model or mathematical equations.

> > This recognition between what we observe (which is observer
> > dependent) and what actual is, is very important, because it is
> > observer independent.
>
> Yes. But every description requires a perspective (coordinates).

This depents what we mean with description.
I prefer a clear distinction between observation (me) and a description (we).
IMO a law is a description of the physical reality
but not every description is directly a law (mathematical construct)

> > In [the world] the actual processes take place.
>
> Yes. Physical processes take place in the world; we humans describe them
> using a MODEL, and such descriptions inherently require a
> perspective/coordinates, because that is how we formulate models.

Here the model should be indepent of our human perspective.
The coordinates used as part of the model should be human independent.

> > In [the world] there is also a clear distinction between processes
> > based on electromagnetic phenomena and gravitational phenomena.
>
> Nonsense.

?
Thats why you should decouple the observations from the descriptions.
This is specific to unravel the laws of falling objects i.e. masses.

> It is our MODELS that distinguish this. Nature just does
> whatever she does (which we do not "know", we only model).

Now this discussion becomes tricky. (It is a yes and a no)
What we humans want is to understand how nature operates.
What we also want is to make/build 'tools' as acurate as possible.
As such we can make tools (a clock) to measure time (or count).
The issue is not all clocks are totally the same.
If that is the case you need a model (description) to clearly
identify what makes the difference and to explain the difference.

See also my reply to jt (posted 16 July) in this discussion.

> We have CHOSEN to use different models for gravitation
> and electrodynamics.

Because these processes are physical different and require
different laws.
A graviton goes straight from A to B. A photon does not
go straight from A to B, when there is something in between.
Of course certain 'aspects' can be the same.
A the bottom line: We can very little learn from thought experiments.

Nicolaas Vroom.

[Tom Roberts]

On 7/17/18 2:55 PM, Nicolaas Vroom wrote:
> The idea is when we try to perform the same experiment the descriptions and
> the results should be the same. (repeatability)

Yes, repetitions should reproduce results.

> You can ofcourse only do that when you remove everything what is observer
> dependent. The description (model) should be observer independent. My
> observations are subjectif. The descriptions should be objectif.

In general, observer-independent descriptions are pretty useless. People nearly
always use coordinates to describe experiments and their results.

> They are subjectif (If that is the correct defintion)

English: subjective: based on or influenced by personal feelings, tastes, or
opinions; in physics: coordinate dependent.

As opposed to objective: not subjective; in physics: coordinate independent.

> But the real description should be observer independent.

Descriptions by observers are "real" (in any useful meaning of the word).

The PHYSICS is observer dependent, but descriptions are usually not.

> This requires a certain transformation to come to one common description. An
> objectif description.

For the situation being discussed (stone dropped on moving train), an objective
description is: the stone follows a geodesic in spacetime (neglecting air);
another would be a list of successive spacetime points it occupies (but that is
very difficult to do without coordinates). Those are pretty useless, compared to
the descriptions by the observers (given earlier).

> But for me physical laws are equivalent to descriptions. A different name is
> model or mathematical equations.

The phrase "physical law" is self-inconsistent and ambiguous: "physical" implies
it is related to the world, while "law" is clearly part of the model.

Some people use "physical law" to mean the (unknown) methods nature uses in the
operation of the world. Other people, like you, use it to mean the models we
humans have collected that describe how the world works. Both are acceptable and
common usage, but one must be clear about which is being used.

> I prefer a clear distinction between observation (me) and a description
> (we).

Such peculiar usage is hopeless, as others will not know what you mean. Personal
vocabularies are confusing (to you and to others); they generally are an attempt
to disguise a misunderstanding on the part of the user.

An aspect of your misunderstanding is:

> The coordinates used as part of the model should be human independent.

That is simply not possible: coordinates are ARBITRARY human constructs.

All humans might agree on the definition of a coordinate system,
so in one sense that is "human independent", but it still
depends in essential ways on humans. Nature does not depend on
humans at all.

> What we humans want is to understand how nature operates.

"Understand" in the sense of "model". As our minds process only thoughts, this
is the best we humans can do.

>> We have CHOSEN to use different models for gravitation and
>> electrodynamics.
>
> Because these processes are physical different and require different laws.

What God whispered in your ear and told you this? -- because that is the only
way you could know it.

To be clear: we humans have divided the world into different domains, one in
which our model of electrodynamics is valid, and a different domain in which our
model of gravitation is valid. Nature recognizes no such separation and no such
domains -- she operates freely throughout the entire world and does whatever it
is that she does. We humans have been forced by our limited knowledge into this
separation, and are fortunate to have discovered separate models of
electrodynamics and gravitation (and their corresponding domains); thinking this
separation also applies to nature is completely unwarranted, and likely wrong.

> [... further variations on divine knowledge (gravitons vs photons, ...)]

Tom Roberts