Why Haven't Two Clocks on a Table Been Used to Measure Light's One-Way Speed?

[outandbeyond2004]

Eyesaw, once again, it was not Einstein who first proposed that the speed of light was a constant. It was a theoretical consequence of Maxwell's equations for electrodynamics, which were based on decades of experiments. Was your computer designed using equations other than Maxwell's? You might as well as assert that it was.

I've come to appreciate how hard it is for some people to accept the notion that the vacuum local speed of light is really a constant. I can't remember whether I started out disbelieving in its constancy before finally accepting it as a scientific fact, but I can't think of any table-top experiment that the average Joe or Joette can do. The GPS devices are good 'experiments,' but one still has to be told that their design requires GR. (I once told a friend that, and he showed amazement, if not disbelief.) I have toured several science fairs by now, and certainly nobody was demonstrating light-speed constancy, ha, ha.

Perhaps what Eyeshaw should do is to apply for a job as particle-accelerator designer. I would be totally staggered if he became one.

 

[Eyesaw]

Originally posted by russ_watters
Heh - so SR is 100 year old dogma while Newtonian physics is 500 year old...what?

Eyesaw and MM, asserting something to be true is not the same as proving it. You guys have made a lot of assertions but have provided only misunderstood interpetations as proof. SR is thoroughly proven. If you wish to overturn it, first learn it. Of course once you learn what it and the evidence for it actually says, you'll realize why it is accepted: it works.

Also, while arguments are welcome, attitudes are not. Lose the attitudes.

You are the one with the attitude. I would not waste my energy trying to explain something to a robot whose designers, running
out of AI chips, replaced with a NI chip- i.e., No Intelligence technology.

 

[Eyesaw]

Originally posted by outandbeyond2004
Eyesaw, once again, it was not Einstein who first proposed that the speed of light was a constant. It was a theoretical consequence of Maxwell's equations for electrodynamics, which were based on decades of experiments. Was your computer designed using equations other than Maxwell's? You might as well as assert that it was.

I've come to appreciate how hard it is for some people to accept the notion that the vacuum local speed of light is really a constant. I can't remember whether I started out disbelieving in its constancy before finally accepting it as a scientific fact, but I can't think of any table-top experiment that the average Joe or Joette can do. The GPS devices are good 'experiments,' but one still has to be told that their design requires GR. (I once told a friend that, and he showed amazement, if not disbelief.) I have toured several science fairs by now, and certainly nobody was demonstrating light-speed constancy, ha, ha.

Perhaps what Eyeshaw should do is to apply for a job as particle-accelerator designer. I would be totally staggered if he became one.

Once again, Maxwell's equations were formulated under the pretext of an ether- this is evident in the fact that the EM propogation equations were wave equations and not equations that describe motion of individual particles. Since Einstein disposed of the ether, he revokes his right to the Maxwell formulation of EM phenomena. So any fanatic of SR should be obligated to produce the derivation of a constant c in vacuum without the Maxwell equations. Show me then
how Einstein arrived at his postulate of a constant c without the
Maxwell equations.

Furthermore, the fact that c is a constant in Maxwell's equations
in no way implies the Galilean transformation for light to be invalid. This rather is a consequence of SR's illiteracy in logic. Nor does it require that c be independent of the velocity of source
or inertial frame. Einstein's two postulates in SR contradict each other and have never been proven by any experiment when they are simultaneously applied.

It's not that c being constant in vacuum is hard for people to believe (since if we are accustomed to the law of inertia alreadyyy and in the absence of any external force, there's no reason c should vary from place to place), but Einstein's illogical requirement that c be constant
for observers moving at a different velocity than the frame in which c was obtained, which resulted in the absurd notions of time dilation and space contraction, which ironically, if SR's logic was taken to its conclusions, could not even exist.

 

[Hurkyl]

Not true. Performing the ball rolling experiment by Galileo would show that the ball always tries to achieve a final height that is equal to its initial height, roughly demonstrating a conservation of energy. And probably by oiling the surface the ball rolled on, he and Newton were able to show friction as a force that slowed down the ball, so that in its absence, the previously demonstrated conservation of energy would require the ball to move for all time.
No contradictions at all. Galileo and Newton merely used inductive reasoning to arrive at the law of inertia.

If I roll a ball downhill (oiled or not), it stays downhill. It's totally illogical to think otherwise. And "friction" is just absurd; the ball slows down because there's nothing to keep it moving!

Law of Inertia! Hah! It is trivially proven false by demonstrating that an object will come to rest on its own!

I bet that you're going to tell me that feathers and bowling balls fall at the same speed too, aren't you?

 

[Eyesaw]

Originally posted by Hurkyl
If I roll a ball downhill (oiled or not), it stays downhill. It's totally illogical to think otherwise. And "friction" is just absurd; the ball slows down because there's nothing to keep it moving!

Law of Inertia! Hah! It is trivially proven false by demonstrating that an object will come to rest on its own!

Actually I like your notion of inertia better (I thought the same myself). But I think Galileo and Newton's law of inertia are made consistent with observation by the different assumptions they make about motion. In G and N's model, motion is carried out by tireless donkeys so that the only way to slow the carriage down is by forcefully removing the donkeys or attaching to the carriage donkeys that move in the opposite direction until the forces are balanced ("force" here having a different meaning than that in F=ma). In your model, the carriage is a Honda Civic, a Lumina, Maxima, e.gs., that requires gas to run and only gives you miles to the gallon.

Otoh, I can't see how Einstein's SR can be made consistent with logic and daily observations. It seems to require that there be an infinite number of predetermined universes.

I bet that you're going to tell me that feathers and bowling balls fall at the same speed too, aren't you?

As a matter of fact, I don't believe they do. And there's an usenet poster with a very high IQ that is currently trying to dispute this notion:

http://www.mazepath.com/uncleal/qz.pdf

 

[outandbeyond2004]

Originally posted by Eyesaw
Once again, Maxwell's equations were formulated under the pretext of an ether-

To be sure, the aether idea was raised and debated long before Maxwell, but I learned electrodynamics without its aid.

Originally posted by Eyesaw
this is evident in the fact that the EM propogation equations were wave equations and not equations that describe motion of individual particles.

What about the Lorentz force law?

Originally posted by Eyesaw
Since Einstein disposed of the ether, he revokes his right to the Maxwell formulation of EM phenomena.

A kind of Yogi Berraism is a saying that makes you want to reply to it, but you just can't think of something good to say, it's so illogical and/or irrelevant. You'd open your mouth to reply then think better of it. And then one minute later you again want to reply but again decide not to. And so on.

Originally posted by Eyesaw
So any fanatic of SR should be obligated to produce the derivation of a constant c in vacuum without the Maxwell equations. Show me then
how Einstein arrived at his postulate of a constant c without the
Maxwell equations.

Who, me? Nay, nay, rather ask God to transport you back to the time when Einstein was pondering such matters on his way to his 1905 SR paper.

Originally posted by Eyesaw
Furthermore, the fact that c is a constant in Maxwell's equations
in no way implies the Galilean transformation for light to be invalid. This rather is a consequence of SR's illiteracy in logic. Nor does it require that c be independent of the velocity of source
or inertial frame. Einstein's two postulates in SR contradict each other and have never been proven by any experiment when they are simultaneously applied.

Eyesaw, what the boys in white ought to do is to take you in a straitjacket off to one of these particle smashers and make you a nice plumb juicy target for these wee lil beasties to smash into and produce lovely data to wow the world and lead us into peace and joy forever.

 

[Nereid]

Eyesaw, in another thread in this very same sub-forum, I post two links to lists (with references) of tests of SR and GR. Your reply to my post was (excerpts): "Yes, I have looked at that webpage before. But before we go over these experiments, I'd still like an answer to how any test can be claimed to have confirmed SR ..."

In a nutshell, the answer to your question is 'you can make quite specific predictions from SR; you can do the experiments and make the observations; when you do, you find that the predictions are correct, to within the experimental/observational errors'. IMHO, that's all you can ask of a theory.

So, let's go look at the experiments on the lists:
1) was a specific prediction from SR made?
2) was that prediction made correctly (e.g. no screw-up in the math)?
3) did the researchers do the experiment/make the observation?
4) were the results consistent with the prediction?

Please tell us which of the experiments, in your mind, have "NO" as the answer to any question.

 

[outandbeyond2004]

I would like to suggest that anybody try to design a system like the GPS withOUT GR (at least the low-velocity, low-stress, weak-gravity version or the Parameterized Post-Newtonian formalism). It can be done, I think. I won't try it myself; I trust GR and suspect it would be a well-nigh impossible feat to pull off. However, if Eyesaw, MM, or someone else actually pulls it off, I may decide to abandon GR, especially if the mathematics is simpler.

Let me apologize to Eyesaw. I thought for a moment that he was kidding. I didn't intend to start a flame war.


The Galilean velocity addition theory HAS been tested -- and found to be wrong for particles traveling at high speeds. I mean if in a frame another frame is traveling at speed v and in the second frame an object is traveling at speed w, then the object is predicted to travel at speed w + v wrt the first frame (that's only if the respective velocities are parallel). Is that what MM, Eyesaw, etal. have in mind, the Galilean velocity addition theory?

 

[Hurkyl]

Otoh, I can't see how Einstein's SR can be made consistent with logic and daily observations.

It can't! SR is indistinguishable from Newton when low velocities are involved, and we already see that Newton is inconsistent with logic and daily observations.

You know, we might have a lot more competent engineers if we drop science from their cirriculum, so we don't lead them astray from the obvious facts of everyday experience!

Furthermore, the fact that c is a constant in Maxwell's equations
in no way implies the Galilean transformation for light to be invalid.

We don't need Maxwell to prove them invalid! We just have to toss a ball straight up while running very fast - it lands behind me, not in my hand!

 

[Eyesaw]

Originally posted by Nereid
Eyesaw, in another thread in this very same sub-forum, I post two links to lists (with references) of tests of SR and GR. Your reply to my post was (excerpts): "Yes, I have looked at that webpage before. But before we go over these experiments, I'd still like an answer to how any test can be claimed to have confirmed SR ..."

In a nutshell, the answer to your question is 'you can make quite specific predictions from SR; you can do the experiments and make the observations; when you do, you find that the predictions are correct, to within the experimental/observational errors'. IMHO, that's all you can ask of a theory.

So, let's go look at the experiments on the lists:
1) was a specific prediction from SR made?
2) was that prediction made correctly (e.g. no screw-up in the math)?
3) did the researchers do the experiment/make the observation?
4) were the results consistent with the prediction?

Please tell us which of the experiments, in your mind, have "NO" as the answer to any question.

That webpage provides references to the literature of the experiments, without details to any of them so not much for discussion there. And it's obvious from the author's commentaries on the experiments that he holds a clear bias for SR results- it's like reading a report on the effects of smoking from the tobacoo companies. If you have details on a specific experiment in mind,
I'm sure we would find some flaw in it since it's clearly impossible for SR's postulates to be correct.

The speed of light being source independent and a constant c relative to the vacuum, yes. That physics is the same in all inertial frames, maybe. That both are true simultaneously- no.

 

[Eyesaw]

Originally posted by Hurkyl
It can't! SR is indistinguishable from Newton when low velocities are involved, and we already see that Newton is inconsistent with logic and daily observations.

Impossible. The classical interpretation of SR requires different
inertial frames to be living in different space and time zones- the resulting time dilation and space contraction effects is what allows the c from a stationary frame to be observed as c from a moving frame. That was the whole purpose for the Lorentz transformation. Thus, metaphysically, SR is not indistinguishable from Newton at any velocity.


Nor have you demonstrated how Newtonian mechanics is inconsistent with logic and daily observations to support your other remark.

We don't need Maxwell to prove them invalid! We just have to toss a ball straight up while running very fast - it lands behind me, not in my hand!

Here you are introducing gravity which isn't even covered by SR. Even so, when you toss the ball straight up, you did not apply horizontal velocity to it so the ball ends up in a different inertial frame than you, when horizontal velocities are compared. This result is in complete agreement with Galilean transformation
whereby the ball's velocity in the horizontal direction is c +/- v as observed by the running person, with c being 0 in this particular case. So, wrong again. Once again, the addition of velocities in different inertial frames is a fundamental statement about motion, space and time- one cannot make a reality based on absolute time and space consistent with one that requires a relative space and time- but this is not to say that SR is even correct in the latter respect.
Try analyzing the motion of the ball using SR with respect to the runner- you run into the scenario I brought up awhile ago of having 3 dimensions for time in SR. Ridiculous.

 

[Martin Miller]

ahrkron wrote:
"Once you have the two clocks' terminal connected to the same source,
you just send the signal. Each will receive half the current, but
they will start prompted by the same pulse."

There are only two problems with this, namely, you have yet to
prove that the pulses travel at equal speeds wrt the clocks, and
you have yet to provide a means of verifying absolute synchronicity.

And, as I said, but as you seemingly ignored, _if_ you had actually
discovered a means of absolutely synchronizing clocks, then you
would be the first.
[Ref: for some others who have tried, see the following:
"Conventionality in Distant Simultaneity," wherein three
proposals for absolute synch are shot down.
Peter Ohrstrom, Found. Phys. 10, 333 (1978).]

 

[Nereid]

Originally posted by Eyesaw
That webpage provides references to the literature of the experiments, without details to any of them so not much for discussion there.

Yes, there are a lot of them, aren't there? Which ones have you performed?

Originally posted by Eyesaw : And it's obvious from the author's commentaries on the experiments that he holds a clear bias for SR results- it's like reading a report on the effects of smoking from the tobacoo companies. If you have details on a specific experiment in mind,

It's not a question of 'bias', it's a question of results. You're the one proposing that SR is invalid (in some way), I'm challenging you to tell us which of the dozens of experiments which are consistent with SR are, in fact, not.

Originally posted by Eyesaw : I'm sure we would find some flaw in it since it's clearly impossible for SR's postulates to be correct.

That's precisely what I'm asking* you to do, show us the flaws in the experiments.

Originally posted by Eyesaw : The speed of light being source independent and a constant c relative to the vacuum, yes. That physics is the same in all inertial frames, maybe. That both are true simultaneously- no.

Experimental or observational results which show this, please!

*For the avoidance of doubt (and at the risk of being painfully repetitious), please look at the experiments on the lists, and for each *you* answer these questions:
1) was a specific prediction from SR made?
2) was that prediction made correctly (e.g. no screw-up in the math)?
3) did the researchers do the experiment/make the observation?
4) were the results consistent with the prediction?

Having done that, please tell us which of the experiments, in your mind, have "NO" as the answer to *any* question.

 

[Eyesaw]

Originally posted by outandbeyond2004
I would like to suggest that anybody try to design a system like the GPS withOUT GR (at least the low-velocity, low-stress, weak-gravity version or the Parameterized Post-Newtonian formalism). It can be done, I think. I won't try it myself; I trust GR and suspect it would be a well-nigh impossible feat to pull off. However, if Eyesaw, MM, or someone else actually pulls it off, I may decide to abandon GR, especially if the mathematics is simpler.

Let me apologize to Eyesaw. I thought for a moment that he was kidding. I didn't intend to start a flame war.


The Galilean velocity addition theory HAS been tested -- and found to be wrong for particles traveling at high speeds. I mean if in a frame another frame is traveling at speed v and in the second frame an object is traveling at speed w, then the object is predicted to travel at speed w + v wrt the first frame (that's only if the respective velocities are parallel). Is that what MM, Eyesaw, etal. have in mind, the Galilean velocity addition theory?

No need for apologies, I don't take flames very seriously anyways and think it's healthy. Sticks and stones... Anyways, please provide the experiments demonstrating the Galilean velocity addition to be incorrect.

 

[Martin Miller]

outandbeyond2004 noted:
"Oh, sorry, I see now that you ARE asserting anisotropy . . . are you? I feel a little confused."

That's funny, I would have bet good money that I said
"In other words, experiment shows that light's one-way
speed varies with frame velocity" in a prior post of
3-16-2004.

outandbeyond2004 noted:
Your P1-P2-light ray does not prove that. It is only a thought experiment;

Name one reason why it cannot be actually done;
in fact, it is done every day by people walking
toward light from the sun or even car headlights.
Not to mention the fact that all of SR is based
on thought experiments.

outandbeyond2004 continued:
... and, more important, your analysis is mistaken or inadequate.
The light ray is going in one direction only. To prove anisotropy
you need to show that speeds in other directions are different.

You are the one who brought up anisotropy; my experiment
disproves Einstein's invariance.

And you have yet to prove either invariance or isotropy.

You also have yet to prove that Einstein's clocks are
correctly synchronized.

You have also yet to present a single piece of experimental
evidence for SR that is untainted by Einstein's clocks.

But I can fully understand why, so don't sweat it.

 

[ahrkron]

Originally posted by Martin Miller
There are only two problems with this, namely, you have yet to
prove that the pulses travel at equal speeds wrt the clocks,

If both clocks are identical, there is no reason to expect otherwise. Anyway, this potential problem is easy to overcome: just reduce the length of the "Y" branches as much as possible. Clearly, there is no reason why this coudln't be zero. Ultimately, you can even attach the two clocks to, say, both sides of the same circuit board, so that they share the exact same input lines (so there are not two pulses).

and you have yet to provide a means of verifying absolute synchronicity.

I did. You just need to let the two clocks run for, say, a day, and then send the stop signal. At that moment, both clocks are programmed to store their final times in memory devices, and both are displayed in a screen. If both show the same number, you know that they are in sych down to one count in a day worth of counts.

As an example, say that they count once per nanosecond (ns) (which is not much; the computer I'm working on has a 2GHz clock, i.e., its clock ticks twice every nanosecond). In a day, you have a total of 86400 seconds, which makes 8.64x10^13 ns. Adjust anything you need until, after a day, you get the two clocks to get the same count. Then you know that they are syncronized to one part in 8.64x10^13. Not bad at all, and good enough to make the measurement for the speed of the space shuttle (8 km/s, which gives a time dilation difference of the order of 10^-9; i.e., the potential experimental error is four orders of magnitude smaller than the difference you want to measure! that allows for a very good measurement)

And, as I said, but as you seemingly ignored, _if_ you had actually
discovered a means of absolutely synchronizing clocks, then you
would be the first.

Time synchronization is not the problem you make of it. There are high speed networks all around us these days. In order for them to work properly, transmitters and receivers need to have similar speeds and to exchange signals at the right times.

 

[outandbeyond2004]

I googled "Michelson-Morley interferometer ("table-top" OR tabletop)"

Guess what, some authors actually propose that a MM interferometer mounted on a table can measure the Milky Way Galaxy mass. Why don't MM, Eyesaw, et. al. construct their own interferometers and try to verify the predictions in the following paper:

Weighing the Milky Way

If one is all thumbs, surely one has techie friends who could help. I am going to send my nephew the URL. Maybe at the next science fair he will wow people.

 

[Nereid]

ahrkron wrote: Time synchronization is not the problem you make of it. There are high speed networks all around us these days. In order for them to work properly, transmitters and receivers need to have similar speeds and to exchange signals at the right times.

To amplify on ahrkron's comment: modern telecoms networks - whether a large office one, or the China Telecom's phone network (>150 million circuits), or anything in between - rely heavily upon accurate synchronisation.

The problem of 'distributing the clocks' is an old one in telecoms, and was solved (from an engineering perspective) a long time ago. There are commercial solutions - http://www.empowerednetworks.com/solution/products/symmetricom.htm -widely available. If you google on 'distributing clock telecom network' (or similar) you'll find a large number of good sites; some of the vendors have extensive product data sheets describing clock synchronisation in much detail.

 

[russ_watters]

Originally posted by Nereid
To amplify on ahrkron's comment: modern telecoms networks - whether a large office one, or the China Telecom's phone network (>150 million circuits), or anything in between - rely heavily upon accurate synchronisation.

At the risk of sounding like a broken record, GPS also requires precise time signal synchronization - to within just a few nanoseconds.

 

[Martin Miller]

ahrkron wrote:
"Time synchronization is not the problem you make of it. There
are high speed networks all around us these days. In order for
them to work properly, transmitters and receivers need to have
similar speeds and to exchange signals at the right times."

It is not my problem - it is SR's and Einstein's problem.
It was Einstein who claimed that he did not possesses the
"means of measuring time." (his words, not mine) Also,
did you not look at the peer-reviewed physics article to
which I referred?

Anyway, let's see if we can clear up this matter via the
following simple question:

Would you please show at least two inertial coordinate
systems' observers using your "synchronized" clocks to
measure light's one-way speed - in full numerical detail?
(I want to see times on all clocks used.)

Although my query just given should be sufficient, I will,
nonetheless, continue to address your reply.

ahrkron wrote:
"If both clocks are identical, there is no reason to expect otherwise.
Anyway, this potential problem is easy to overcome: just reduce the
length of the "Y" branches as much as possible ..."

I agree with you that very closely-spaced clocks can be nearly
absolutely synched, but I was speaking of absolute synchronization
in theory. That is, you must tell us how to absolutely synchronize
two clocks which may be 10,000 light-years apart.

quote:
and you have yet to provide a means of verifying absolute synchronicity.

ahrkron wrote:
"I did. You just need to let the two clocks run for, say, a day, and
then send the stop signal."

How do you know that the stop signal travels at equal speeds
wrt the clocks?

ahrkron wrote:
"... Then you know that they are syncronized to one part in 8.64x10^13.
Not bad at all, ..."

No, not bad for use on Earth, but try it for two clocks which are
moving at 90% light speed and are 10 light-years apart.

Please remember that all physicists and all other scientists
have only **one** definition of clock synchronization, namely,
Albert Einstein's, and it merely assumes one-way light speed
isotropy and invariance, and does not prove it. (Actually,
it is not really an assumption because it cannot be proved
because there is nothing to be proved -- it is a merely a
mandate that forces clocks to obtain one-way invariance and
isotropy. If anyone believes otherwise, then let her or him show
on paper how it can be proved or tested experimentally.)

 

[Martin Miller]

Eyesaw noted:
"You had the right idea but this experiment is flawed.
The X distance the light traveled with respect to your
thought experiment is different for p1 and p2. ..."

The experiment was designed to fit within the
context of SR, which involves measurements wrt
inertial coordinate systems.

To explain further:
Let's say that you and I are in different frames whose
x axes are parallel. I am at my frame's origin, and
you are at your frame's origin. At the moment that
these two origins meet in passing, suppose an explosive
event occurs some distance away near our frames' x axes.
Suppose this explosion burns spots on both axes. All
SR proponents will say that we will each measure the
_same_ distance from our origin to the burn mark on our
x axis. This is why I said that the approaching light
ray traveled the _same_ distance wrt the observers.

 

[outandbeyond2004]

Well, Martin Miller does have a good point, in a way. We can synchronize nearby clocks all we want, but what about events say 10 LY distant? We can't transport any clock there in any practical way; and even if we use FTL transport, how do we know that the transported clock stays synchronized?

Well, I hate to admit it, but we just assume that an hydrogen molecule there acts like an hydrogen molecule in the lab. Synchronization between a distant hydrogen molecule and a lab hydrogen molecule? You win

Indeed, a dirty secret in science is that astrophysics is done on the assumption that whatever happens in the lab also applies in a general way to what happens out there. That's all it is, just an assumption. The laws of physics on Earth are the same in distant places of the universe, I hope.

But, Martin, are you going to reject everything just because it is based on assumptions like the above? If you do, why are they so unreasonable? They are not proven and may never be, but are they really unreasonable?

 

[russ_watters]

Originally posted by outandbeyond2004
Well, Martin Miller does have a good point, in a way. We can synchronize nearby clocks all we want, but what about events say 10 LY distant? We can't transport any clock there in any practical way; and even if we use FTL transport, how do we know that the transported clock stays synchronized?

For synchronizing clocks in different reference frames, we use SR and GR: again, like they do with GPS.

 

[Hurkyl]

Even so, when you toss the ball straight up, you did not apply horizontal velocity to it so the ball ends up in a different inertial frame than you

*boggle*

You do realize that Galilean relativity says that if I throw a ball straight up (by my reckoning), it should come straight down and bonk me on the head, don't you?


It, of course, doesn't happen, because the ball will land behind me; I have to throw it slightly forward in order for it to bonk me on the head.

 

[selfAdjoint]

The first postulate of SR is that an inertial observer sees all physics the same as he would if at rest. Including the effects of local gravity, to a high degree of approximation. This is Galilean relativity. If you stand still on the surface of an airless, rotating planet and throw up a ball, it will have the same tangential speed as you do and will rise and fall, from your point of view, just as if you were at rest. And it will come down and bonk you.

Now if you project the ball very hard, so that it soars high, then maybe tidal effects will have some effect, but that is very very small. Basically Galilean relativiy rules, and your theories of what happens are wrong.

 

[Eyesaw]

Originally posted by Hurkyl
*boggle*

You do realize that Galilean relativity says that if I throw a ball straight up (by my reckoning), it should come straight down and bonk me on the head, don't you?

Only if you threw the ball up while standing still. If you threw the ball up then ran away from it, it will obviously fall away from you since you gained velocity in the horizontal direction with respect to the Earth frame while the ball did not.

It, of course, doesn't happen, because the ball will land behind me; I have to throw it slightly forward in order for it to bonk me on the head.

The ball will not land behind you if never ran away from it. GAlilean relativity most definitely does not predict the ball to fall behind you if you threw it while standing still with respect to the Earth frame. This simple motion of the ball on the other hand cannot be analyzed by SR since the ball is in an accelerated frame with respect to you and is also moving in a direction perpedicular to your motion so that you end up with time dilation and space contraction in two different directions. Absurd.

 

[Eyesaw]

Originally posted by selfAdjoint
The first postulate of SR is that an inertial observer sees all physics the same as he would if at rest. Including the effects of local gravity, to a high degree of approximation. This is Galilean relativity. If you stand still on the surface of an airless, rotating planet and throw up a ball, it will have the same tangential speed as you do and will rise and fall, from your point of view, just as if you were at rest. And it will come down and bonk you.

Now if you project the ball very hard, so that it soars high, then maybe tidal effects will have some effect, but that is very very small. Basically Galilean relativiy rules, and your theories of what happens are wrong.

The postulate Galilean relativity and SR have in common is the one that says that physics is the same in all inertial frames. I don't think GAlileo every mentioned about transforming events from one inertial frame to another but if one were to do so then obviously something moving at c, y, m, l, j, a, b, d, e, x, n, s, q, et al in a "rest" frame would have a velocity of c +/- v after transforming coordinates. This is the logical consequence of the addition or subtraction of velocity to the rest coordinates.

The relevant point here is that after transforming coordinates by Galilean relativity, the c, representing a physical constant maybe,
can remain a constant only if we make the additional assumption of source dependency. This c could be the speed of light for example as measured in an inertial frame.

SR on the other hand introduces a postulate that contradicts the first postulate. That's why any attempts at physical interpretation led to paradox.

 

[Hurkyl]

Only if you threw the ball up while standing still.

While running, I am still in the inertial reference frame centered on me.

This is the logical consequence of the addition or subtraction of velocity to the rest coordinates.

And why should we believe in addition/subtraction of velocity to the rest coordinates? It is this assumption that SR contradicts.


Shall I remind you that the assumption that "All physical laws are the same in all inertial reference frames" implies that the speed of an electromagnetic wave is the same in every reference frame, ala Maxwell's theory of Electrodynamics?

 

[outandbeyond2004]

Eyesaw, perhaps you have a techie friend who would enjoy cobbling together a tabletop Michelson-Morley interferometer using spare parts. He could then demonstrate for you personally that the postulate of linear velocity addition is not natural, contrary to what you think is logical.

 

[Eyesaw]

Originally posted by Hurkyl
While running, I am still in the inertial reference frame centered on me.

No, Inertial frames are distinguished by the difference in velocity they have between them. When you start running, you change your inertial frame. Thus if you threw the ball upwards while standing and afterwards proceeded to run horizontally away from it, you and the ball end up in different inertial frames, whether under Galilean Relativity or SR. Only if you threw the ball while running, at constant velocity, will it be in the same inertial frame as you
and therefore fall down to bonk you- of course such an experiment
is difficult to perform because of the difference in air drag e.g.

And why should we believe in addition/subtraction of velocity to the rest coordinates? It is this assumption that SR contradicts.

Because 1+1 = 2. Because 2+2 = 4. Because 3+3=6. Because 5+5=10. Because if J is moving at c relative to M, and L is moving at v relative to M, then J must be moving at c +/- v relative to L or else we arrive at the contradiction that L is not moving relative to M.

Shall I remind you that the assumption that "All physical laws are the same in all inertial reference frames" implies that the speed of an electromagnetic wave is the same in every reference frame, ala Maxwell's theory of Electrodynamics?

And as I already explained in response to self-adjoint, any physical law can be made constant in Galilean relativity by assuming source dependency. SR assumed source independency, that's what resulted in contradiction. You can logically assume source independency only if physical laws are frame dependent.

 

[Hurkyl]

Only if you threw the ball while running, at constant velocity, will it be in the same inertial frame as you
and therefore fall down to bonk you- of course such an experiment
is difficult to perform because of the difference in air drag e.g.

This is the point I was trying to make that got lost in the parody.

Experience "proves" Galilean relativity wrong because of air drag. If I'm running and I throw a ball up, it falls behind me, which seems to contradicts Galilean relativity. However, if you were the type who didn't want to believe in Galilean relativity, you could easily use this scenario to rationalize your belief that Galilean relativity is false.

Because if J is moving at c relative to M, and L is moving at v relative to M, then J must be moving at c +/- v relative to L or else we arrive at the contradiction that L is moving relative to M.

What's the contradiction? Are you assuming that if M measures the distance between J and L, then L simultaneously measures the same distance?

And as I already explained in response to self-adjoint, any physical law can be made constant in Galilean relativity by assuming source dependency.

Funny, I've never seen a consistent version of Maxwell's equations that has source dependancy.

 

[outandbeyond2004]

Originally posted by Eyesaw

Because 1+1 = 2. Because 2+2 = 4. Because 3+3=6. Because 5+5=10. Because if J is moving at c relative to M, and L is moving at v relative to M, then J must be moving at c +/- v relative to L or else we arrive at the contradiction that L is moving relative to M.

Do you have an analysis of the Michelson-Morley interferometer experiment?

Also, how do you explain this experiment with a magnetometer at rest wrt a electrically charged ball: The magnetometer registers zero, but if it moves at speed v wrt the ball, it registers the strength of a magnetic field in proportion to v?

 

[Eyesaw]

Originally posted by outandbeyond2004
Do you have an analysis of the Michelson-Morley interferometer experiment?

Some descriptions of the Michelson Morley experiments differ from others- I shall use this one for my answer :http://galileoandeinstein.physics.virginia.edu/lectures/michelson.html

Using Galilean relativity, the null result can be explained either assuming the light is source dependent or not, weird as it seems. In the case of source independence, the horizontal path (assuming this is the direction of motion of the Earth through space) traveled by the light would be L+v in the direction of the Earth's motion and L-v going back for a round trip distance of 2L. In the vertical path, the distance is just L up and L down for a roundtrip of 2L. Since both vertical and horizontal paths are equal, a null result is obtained. The argument applies even when the apparatus is turned.

In the case of source dependence, the time traveled for the light would be (M+v) - v in the direction of Earth motion and (M-v) + v going back for a roundtrip time of 2M. Vertically, the time of flight would be (M+( hypotenuse displacement of light)) - ((hypotenuse displacement of velocity of source)) upwards and the same back down for a roundtrip time of (M+N) - N + (M+N) -N = 2M. Since both times are equal, the result is again a nullshift.

It seems a little strange that both assumptions lead to a null result so feel free to double check my calculations.

OTOH, interpreting the MMX using SR results in a contradiction. Taking the detector as the inertial frame (which would include the whole apparatus), it would say the apparatus is in a frame that is both time dilated and not time dilated , space contracted and not space contracted - since it would need time dilation and length contraction to explain the light traveling at c in a frame that is moving relative to a frame that is not moving with respect to the EArth. But this is no surprise since the theory uses two contradicting postulates.

If anything the MMX disproves SR, as any real experiment should. The weird result obtained for Galilean relativity is because we used the roundtrip speed of light and also because we assumed there is no stationary ether that can drag the light. That's about the only thing MMX proves- that light is not being dragged by a stationary ether.

 

[Martin Miller]

outandbeyond2004 wrote:
"... Synchronization between a distant hydrogen molecule and
a lab hydrogen molecule? You win"

"Indeed, a dirty secret in science is that astrophysics is done
on the assumption that whatever happens in the lab also applies
in a general way to what happens out there. That's all it is,
just an assumption. The laws of physics on Earth are the same
in distant places of the universe, I hope."

"But, Martin, are you going to reject everything just because it
is based on assumptions like the above? If you do, why are they
so unreasonable? They are not proven and may never be, but are
they really unreasonable?"

----
russ_watters noted:
"For synchronizing clocks in different reference frames, we use
SR and GR: again, like they do with GPS."

russ_waters also wrote the following in a slightly earlier post:
"At the risk of sounding like a broken record, GPS also requires
precise time signal synchronization - to within just a few nanoseconds."

----

MM replies (sans any hope of really getting thru, so it's basically
just for the record):
Empty claims of absolute synchronization (as in the above cases)
are not proofs of it.

FYI: There is only one way to prove absolute synchronization,
and that is by showing step-by-step how it can be done. (This
involves the necessary step of providing the verification
process.)

I would add that anyone who claims to be able to absolutely
synchronize clocks should also show what happens to light's
one-way speed when it is measured by said clocks.

Also, I should add that anyone who finds a way to absolutely
synchronize clocks will thereby disprove special relativity,
which of course has only relative simultaneity. (This includes
the scientists involved in the GPS system, but none of them has
publicly claimed to have found absolute synchronization.)

My prediction re the above is that no one in this forum will
ever show the required step-by-step proof of absolute clock
synchronization. (In fact, if I were wealthy, I would bet
big bucks on it!)

 

[Eyesaw]

Originally posted by Hurkyl
This is the point I was trying to make that got lost in the parody.

Experience "proves" Galilean relativity wrong because of air drag. If I'm running and I throw a ball up, it falls behind me, which seems to contradicts Galilean relativity. However, if you were the type who didn't want to believe in Galilean relativity, you could easily use this scenario to rationalize your belief that Galilean relativity is false.

No, what it shows is that you can continue burning calories to overcome airdrag to keep at a constant velocity while the ball cannot because it doesn't have a digestive system for one. I don't think you've even tried this experiment yourself by the way. I'm in my office right now, which can be considered an inertial frame since everything in it are stationary. While standing in one place, I throw a ball in the air and it falls down in my hand. If I throw it upwards and then run away from the ball, it falls behind me. I then started running with the ball in my hand and after I throw it- as vertically as possible- it falls in my hand, not behind me.

But there are much better illustrations then your experiment that clearly demonstrates the validity of Galilean relativity and the Galilean addition law. In a car moving at 25 miles per hour with the windows rolled up while seated, throw a ball vertically and see if it flies to the back or lands in your hand.

I still think you are joking because I've never heard anyone dispute the validity of Galilean relativity in every day observations because it's so easily verified.

What's the contradiction? Are you assuming that if M measures the distance between J and L, then L simultaneously measures the same distance?

The contradiction is that we started out assuming there is velocity between M and L, then using J as a standard by which the velocity between M and L are to be determined. The only way J can have the same value for both M and L then is if there is no velocity between them, contradicting our starting assumption that there was. This is a reductio absurdum.

Funny, I've never seen a consistent version of Maxwell's equations that has source dependancy.

The postulate of physics being the same in all inertial frames makes any transformation equation redundant. Since the postulate is a statement about physics inside an inertial frame, of what relevance is it to transform an event into a different inertial frame? And this postulate is definitely not specific to the Lorentz Transformations since one can just as well transform the value C in one inertial frame using the Galilean transformation then adding or subtracting v to the c-value in the new frame to obtain the universal constant C, i.e. by assuming source dependency. The main difference is that the Lorentz Transformation starts out by assuming absolute space-time but then rejects it in the same equations in order to make C a universal constant- i.e. it results in physical and logical nonsense.