I’m trying to establish from first principles how relativity made its fundamental assumptions and how it was built up from there on.

It appears that there are three fundamental observations and hence measurements that we can use to establish a theory such as relativity, these are:

Time
Length
Mass

These 3 fundamental base units are the foundations from which relativity was created and the other four base units, such as temperature, are unnecessary for us to consider. I think it is safe to say that other derivatives such as acceleration, speed, frequency, force or energy are founded from the above three and can also be ignored whilst considering the fundament assumptions.

I’d like to leave mass for the moment and begin with time and length.

The definition of time is based on the fact that an arbitrarily chosen “second” here on Earth happens to be 9192631770 cycles of a Caesium atomic clock. Why this number of cycles was chosen is meaningless and unnecessary for us to consider.

The Caesium clock functions as a regulated bunch of measurable events that can be compared with any other distinguishable events. Once an event has been communicated to our timepiece, we can start or stop it, thus recording the number of cycles of our clock in comparison with ANY other event that has been communicated with the Caesium clock. From this we can only draw conclusions based on the notion that we are only measuring one set of physical events relative to our chosen set of regulated events. This is what time is and in my view, a perfectly acceptable and irrefutable argument.

When two Caesium clocks are separated they “experience” completely different environments whilst apart. One may have forces applied to it causing it to accelerate. One clock might be at a different altitude relative to the other, and hence in a different gravitational field. One could be travelling through space at a higher velocity than the other and be affected by the fabric of space. One or more of these factors must be responsible for the disparity measured between clocks when they are reunited. The possibility that clocks are affected in a physical way, rather than time itself dilating, is a viable idea but, once again, I find this idea difficult to prove (or disprove, for that matter).

Despite these ideas being fundamentally different to the ideas from which relativity was based (i.e. time dilates), the result remains the same and relativity remains intact. 1 – nil to relativity.

However, you need to bear in mind that IF Caesium atoms ARE physically affected by the fabric of space (whatever this might be), this induces the idea of an as-yet undetected substance / energy which pervades space. This fabric might not necessarily be responsible for the propagation of EM waves, but could easily affect matter itself (possibly being responsible for gravity). Again, particularly with current speculation regarding dark energy, I can see no compelling argument for not agreeing with this possibility, especially as gravity remains largely a mystery.

However, being as this substance is undetectable, relativity retains its strength and is unaffected, regardless. 2 - nil to relativity.

Moving on, lets consider length.

Of course, length too is a totally arbitrary unit of determining the relative distances between physical events or measurable entities. We happen to use the SI unit of the metre to make our relative measurements with, which we happen to have chosen as being the distance that light travels in 9192631770/299792458 cycles of a Caesium clock. But hold on a minute….this means that if the apparent dilation of time is actually down to a physical phenomenon, then in this case, lengths measured in different places of the universe will be affected by the cycles of the clock changing from one place to another. I guess this means that the measured length of, say, a 1m stick would be erroneous due to our atomic clock slowing down and our equations incorporating a fixed light speed to take care of this. This brings me on to my next associated problem, which is how length is defined, i.e.that we use light to define the exact length of a metre. Hmmm, sound a bit dodgy to me because as JamesR once said “nobody knows why light always appears to travel at the same relative speed to an observer – it’s a mystery”. This begs the question as to whether we really DO have an understanding of reality and the massive assumptions that relativity is built from. I have previously put forward the notion that light only APPEARS to travel at a constant speed due to the limitations of our measuring equipment, i.e. we are attempting to measure the speed of light USING light, and this has a serious consequence as to our interpretation of what we are measuring as opposed to what is REALLY happening.

However, all said and done, relativity successfully describes our universe as seen from the perspective of an observer/traveller and relativity seems impenetrable regardless of what wonderful and weird alternatives we may come up with. I have been taking a keen interest in this subject for quite some time now and despite this post being a repeat of what I have said before, I feel it is beneficial to new forum readers who are interested and beginning to doubt relativity.

Basically, I am certain (at least in my own mind) that relativity is nothing more than a mathematical model that helps describe and predict our observations from our frame of reference. It has no link with reality and doesn’t claim to have. It is founded on the basis of assumptions that cannot be refuted due to the nature of our measurement systems, and this provides relativity with the rigidity that has helped ensure its durability and longevity.

I can’t help thinking though, that there is a sting in the tail and that relativity may well be the victim of its own success. The fact that relativity is constantly proven correct distracts from other theories that could be founded and developed from completely different assumptions. It seems that anyone’s “alternative” ideas are blown out the window without any careful consideration whatsoever. And relativists have a ball of a time in the process of undermining these ideas as useless. With the inability to prove any alternative ideas, anti-relativist are faced with a hopeless case.

Personally, I think relativity is a brilliantly thought out mathematical model of equation manipulation. And I can’t see how anyone can argue with it! I just can’t help feel that it is based on the wrong assumptions and my gut feeling tells me something is VERY wrong with the model’s fundamentals. My main problem is that of the sol remaining constant to all observers because it just doesn’t make sense - accepting this must be hard for even the most experienced relativists!

I present a problem for someone to please answer and explain (it may help my understanding)….

If a light beam sent from a Planet A, has attached to it a simple message. Lets say the message is nothing more than a whole bunch of digits and lets say that the digits are separated equally and there are a total of one million released over a period of 100 seconds (all relative to Planet A). Don’t forget that the digits (or pulses) are separated by an equal number of whole waves of light and lets suppose that the light beam is of a single frequency to make life easy. Now then, Planet A has emitted this ray of light on the basis that the sol is the same to all observers and the aim of the experiment is simple: to establish if ALL recipients of the message respond with a verification message that they, indeed, received the one million pulses in EXACTLY 100 seconds. Only then can we verify that ALL observers are travelling at the same speed relative to the emitted signal from Planet A.

I’d like to consider the difference between two rockets, one stationary (Rocket 1) with respect to Planet A and one approaching Planet A (Rocket 2) at 0.9 the sol. From what I can see, Rocket 2 experiences a significant blue-shift of light and manages to collect the one million digits in a shorter period of time.

If Rocket 2 can manage to do this, then this to me indicates that Rocket 2 must have travelled past the beam of light faster than Rocket 1. There is a clear difference in experiences between Rocket 1 and 2 whilst taking measurements from the same source. This surely is conclusive evidence that the sol is not constant to all observers.

Alas!

this time also Albert defeats your scheme.

rocket B moves .9c and its dilated time is 1/sqrt(1-.81) times the earth second.

dilated time of rocket b unfortunately can explain how it could manage to collect all the digits in less than 100s (earth time).

sorry, modify the setup. ;)

I’m trying to establish from first principles how relativity made its fundamental assumptions and how it was built up from there on.

It appears that there are three fundamental observations and hence measurements that we can use to establish a theory such as relativity, these are:

Time
Length
Mass

These 3 fundamental base units are the foundations from which relativity was created and the other four base units, such as temperature, are unnecessary for us to consider. I think it is safe to say that other derivatives such as acceleration, speed, frequency, force or energy are founded from the above three and can also be ignored whilst considering the fundament assumptions.


dav57,
You will be receiving many variations to answers given, here is another.

Before tackling your specific problem directly we need an understanding between us. When Einstein described his SR in his 1916 book "Relativity" he showed us his reasoning in how he came about his version of the constancy of the speed of light.

A man walking on a train movibng wrt the embankmnet is observed from the embankment as moving Vme = Vte + Vmt, or the velocity of the man with respect to the embankment is the sum of the velocity of the train wrt the embankment plus the velocity of the man, wrt the train assumed at rest wrt the man. Thjis is all classically verified.

Now when AE uses light instead of gthe man he uses the same physics and logic. The speed of light with respect to the embankment Vce,(in vacua)is equal to the speed of the train wrt the embankment Vte, plus the speed of light wrt the train Vct. Therfore AE writes Vce = Vte + Vct, or Vce - Vte = Vct. Here AE reminds us that the speed of light comes out less than Vce, so therefore we must make some adjustments. However, when we write Vct = Vce - Vct we have just subtracted the velocity of the train wrt the embankment instead of assuming the train is at rest wrt the light. This assumption assume a dependency between the speed of light and the speed of the source of the light. AE knew about the independency of the speed of light as he started the chapter where the above is described in the first couple of paragraphs.

Now when we substitue Vct = V'ce - Vct into Vce = Vte + Vce - Vct, (in V'ce the speed of light wrt the embankment, the prime means emitted on the moving train)or Vce =V'ce with the understanding the right hand side is the light emitted on the moving train. AE knew of De Sitter's work showing tghe physical "proof" that the speed of light is independent of the speed of the source of the light.

If you see why the speed of the train was subtracted instead of assumed at rest, then you see the fallacy of AE's views that the speed of light, including relative speed, is always measured at C is a physically improper description of the motion of light.

To be sure, the speed of light is C measured from all inertial frames, however the relative speed of frame and photon is C - Vt, which is a statement not lessening the speed of light, rather it tells us how much faster is the speed of light than the speed of the inertial frame.

The following post is a respeonce to your experiment.
Geistkiesel :cool:

I present a problem for someone to please answer and explain (it may help my understanding)….

If a light beam sent from a Planet A, has attached to it a simple message. Lets say the message is nothing more than a whole bunch of digits and lets say that the digits are separated equally and there are a total of one million released over a period of 100 seconds (all relative to Planet A). Don’t forget that the digits (or pulses) are separated by an equal number of whole waves of light and lets suppose that the light beam is of a single frequency to make life easy. Now then, Planet A has emitted this ray of light on the basis that the sol is the same to all observers and the aim of the experiment is simple: to establish if ALL recipients of the message respond with a verification message that they, indeed, received the one million pulses in EXACTLY 100 seconds. Only then can we verify that ALL observers are travelling at the same speed relative to the emitted signal from Planet A.

I’d like to consider the difference between two rockets, one stationary (Rocket 1) with respect to Planet A and one approaching Planet A (Rocket 2) at 0.9 the sol. From what I can see, Rocket 2 experiences a significant blue-shift of light and manages to collect the one million digits in a shorter period of time.

If Rocket 2 can manage to do this, then this to me indicates that Rocket 2 must have travelled past the beam of light faster than Rocket 1. There is a clear difference in experiences between Rocket 1 and 2 whilst taking measurements from the same source. This surely is conclusive evidence that the sol is not constant to all observers.

The speed of light is the same for all observers, but the relative speed of frame and photon is C - V, which SR asumes is C - V, where V = 0, always.

For the tail of the signal to completely pass the tail of R2 in t'' the distance traveled is ct'' = 10⁶t/100 s. + .9t'', or t'' = 10⁴t/(1 - .9)[for a = 1], or
t'' = 10⁵t sec
is the loading time for the signal to be completely absorbed by R2.

Calculating ct'' for R1 at rest wrt A we use the same form of expression used for R2, but here the second term is zero so,
ct'' = 10⁶/100s, or ct'' = 10⁴t, or the loading time for the rocket at rest wrt A is,

t'' = 10⁴t sec,

The rocket pulling away from the signal takes 10 times as long to completely be absorbed wrt the rocket at rest wrt the planet A.
Geistkiesel :cool:

The speed of light is the same for all observers, but the relative speed of frame and photon is C - V, which SR asumes is C - V, where V = 0, always.

For the tail of the signal to completely pass the tail of R2 in t'' the distance traveled is ct'' = 10⁶t/100 s. + .9t'', or t'' = 10⁴t/(1 - .9)[for a = 1], or
t'' = 10⁵t sec
is the loading time for the signal to be completely absorbed by R2.

Calculating ct'' for R1 at rest wrt A we use the same form of expression used for R2, but here the second term is zero so,
ct'' = 10⁶/100s, or ct'' = 10⁴t, or the loading time for the rocket at rest wrt A is,

t'' = 10⁴t sec,

The rocket pulling away from the signal takes 10 times as long to completely be absorbed wrt the rocket at rest wrt the planet A.
Geistkiesel :cool:

Geistkiesel:
I think I said that the Rockets were approaching the Planet, but that is neither here or there.
Basically, I’m interested in the fact that the two Rockets experience very different outcomes with regard to the time taken to collect the data from start to finish.
I know that the beam of light is the same for both rockets. Likewise, I know the Planet hasn’t moved and therefore if one Rocket is taking a different amount of time to collect the same data, which is directly linked to the beam of light, this can only mean one thing. The rockets MUST be travelling at different speeds relative to the light beam.
After the experiment has been completed, the two rocket astronauts compare notes and find that one has managed to collect the data faster (or slower) than the other with respect to their own proper times. They both conclude that the faster they go, the quicker they can collect data from the same light source. Is this right?

Dear Dav,

U r tryin 2 fight 100 years of EGo bashing. Thoes who study relativity are shrouded from reality forever. It sound like insult of greate scientist when one challanges relativity.


. . .
After the experiment has been completed, the two rocket astronauts compare notes and find that one has managed to collect the data faster (or slower) than the other with respect to their own proper times. They both conclude that the faster they go, the quicker they can collect data from the same light source. Is this right?

The problem is that , U will be argued that because approaching Rocketś time had slowed down it is bound to collect the light at a faster rate. If you record a flim in slow speed , the out come wil be a faster video.

So there is no point in arguing anything about relativity;
The best thing to do is devise such foolproof and strong experiments that relativist will have to bite off their finger to their outcomes.

I have one such; ie. If they talk about atomic clocks and refuse that the clocks are affected by ether or something then thats because the atomic clock experiment is incomplete. There should be two types of atomic clocks used (total 4 clocks), each with different element. If something other than timedialation is affecting the time results then it should affect different to different elements ...

Alas!

this time also Albert defeats your scheme.

rocket B moves .9c and its dilated time is 1/sqrt(1-.81) times the earth second.

dilated time of rocket b unfortunately can explain how it could manage to collect all the digits in less than 100s (earth time).

sorry, modify the setup. ;)

You misunderstand. FORGET Planet A's time. It is meaningless in this experiment. The only thing we're interested in is the stopwatches contained onboard Rocket 1 and 2 and how long each Rocket takes to collect data from the same already emitted source.

Get it? All the crew have to do is scribble down on a bit of paper how long it took to receive the 1 million digits. When the two Rockets unite, they compare their disparity and ponder over what happened. The conclusion has to be that one rocket was travelling faster (relative to the light beam) than the other.

Remember that the digits are directly attached to the light beam and thus any change in collection of digits is a direct result of the rocket moving past the light beam FASTER. i.e. SOL is NOT constant but rather just APPEARS that way because when we attempt to measure it we only take into consideration the wavelength and the frequency. As WL goes up (due to the fact that we haven't got the capacity to measure the correct unchanged wavelength), the frequency goes down, rendering a null change in velocity WRT the light beam.

Does this fact not get you relativist down :bugeye:

Remember that the digits are directly attached to the light beam and thus any change in collection of digits is a direct result of the rocket moving past the light beam FASTER. i.e. SOL is NOT constant but rather just APPEARS that way because when we attempt to measure it we only take into consideration the wavelength and the frequency. As WL goes up (due to the fact that we haven't got the capacity to measure the correct unchanged wavelength), the frequency goes down, rendering a null change in velocity WRT the light beam.

You have a point about there apparently being a limitation as to our ability to measure (locally) anything faster than the speed of light. I believe this is usually explained as time dilation. Other reference frames can see the rocket moving into the light beam at velocity Vr and they can calulate that the rocket and the light speeds are additive:

Vr + c > c

But people on the rocket are time dilated, and so they cannot experience it that way. For them, c = c no matter what.

You seem to be proposing that doppler blue-shift might really be evidence of an increased speed of wave propagation. I would say that this can only be true with waves that require a medium, such as sound. If you ride your motorcycle through a volume of air that contains oncoming sound waves, you get both a blue-shift (higher sound frequency) and an increase in the measured speed of sound relative to your motorbike. This is because you are moving relative to the air, which is the wave's physical medium.

However, it does not work the same way with light. You can ride in your rocket through a vacuum that contains oncoming light rays, but this only gives you a blue-shift. There is no increase in the measured speed of light relative to the rocket. I suppose one explanation is that you cannot really transverse linearly relative to the nothingness of a vacuum. However, the more accurate reasoning would be that information simply cannot propagate at a speed greater than c in a vacuum.


Does this fact not get you relativist down :bugeye:
I doubt realtivists have much of a problem with it. But this is the kind of thing that keeps me thinking about it over and over.

Geistkiesel:
I think I said that the Rockets were approaching the Planet, but that is neither here or there.
Basically, I’m interested in the fact that the two Rockets experience very different outcomes with regard to the time taken to collect the data from start to finish.
I know that the beam of light is the same for both rockets. Likewise, I know the Planet hasn’t moved and therefore if one Rocket is taking a different amount of time to collect the same data, which is directly linked to the beam of light, this can only mean one thing. The rockets MUST be travelling at different speeds relative to the light beam.
After the experiment has been completed, the two rocket astronauts compare notes and find that one has managed to collect the data faster (or slower) than the other with respect to their own proper times. They both conclude that the faster they go, the quicker they can collect data from the same light source. Is this right?
Dav57,
Yes you are correct. Sorry I misinterpreted the directions of the rockets, but your understanding remains unperturbed.

Geistkiesel :cool:

You misunderstand. FORGET Planet A's time. It is meaningless in this experiment. The only thing we're interested in is the stopwatches contained onboard Rocket 1 and 2 and how long each Rocket takes to collect data from the same already emitted source.

How can you FORGET Planet A's time? Your million signals / 100ns in planet time as you said :
there are a total of one million released over a period of 100 seconds (all relative to Planet A).

-----------

Your way of doing experiment, even if its only thought experiment, is odd :


Get it? All the crew have to do is scribble down on a bit of paper how long it took to receive the 1 million digits. When the two Rockets unite, they compare their disparity and ponder over what happened. The conclusion has to be that one rocket was travelling faster (relative to the light beam) than the other.

Remember that the digits are directly attached to the light beam and thus any change in collection of digits is a direct result of the rocket moving past the light beam FASTER. i.e. SOL is NOT constant but rather just APPEARS that way because when we attempt to measure it we only take into consideration the wavelength and the frequency. As WL goes up (due to the fact that we haven't got the capacity to measure the correct unchanged wavelength), the frequency goes down, rendering a null change in velocity WRT the light beam.

You need to get it first that,

(1) SR time dilation was derived from the constancy of c.

(2) You are trying to derive a variable c from an assumption that Planet, rocket A & B all have same time - a common time.

Premises of (1) is well supported by experiments.

Your premises and conclusion are circular.



Does this fact not get you relativist down :bugeye:

You started believing the expected result of your thought experiment is a FACT?

How can you FORGET Planet A's time? Your million signals / 100ns in planet time as you said :


-----------

Your way of doing experiment, even if its only thought experiment, is odd :




You need to get it first that,

(1) SR time dilation was derived from the constancy of c.

(2) You are trying to derive a variable c from an assumption that Planet, rocket A & B all have same time - a common time.

Premises of (1) is well supported by experiments.

Your premises and conclusion are circular.





You started believing the expected result of your thought experiment is a FACT?

Everneo,

Why do you always try to complicate what is really very simple?

I'm not going to repeat the thought experiment over and over but the fact is that two different rockets travelling at different speeds relative to ANY light source will be able to collect data at a different rate to the other, and this is from the SAME light beam regardless of where the light beam originated.

I know SR time dilation was derived from the consistency of c, but my posts describe the possible faults with our measurement abilities. i.e. that we don't have the ability to measure the TRUE unchanged wavelength of the blue-shifted light due to the fact that we are measuring it USING light, meaning we have a communication barrier problem.

This would explain why c APPARENTLY always measures c, but why the rockets are able to extract the data at different rates.

It's just SO obvious, it smacks you in the face! And there's nothing "odd" about my thought experiment.

And you ALWAYS make out I'm saying things that I'm not! I have never once said that I believe in a common time, and neither does this experiment require a common time.

Get to the point and explain why one crew says "hey I've just picked up a message from a light beam that took me 100s on my stopwatch" and the other crew says "hey, but I travelled a bit faster and picked up the same message from the same light beam in a much faster / slower time on MY stopwatch". They compare notes and deduce that only one thing can be happening here - that the rockets were travelling at different speeds relative to the message and, hence, relative to the thing which is carrying the message (light).

Why can't you admit I have a valid point?

Unfortunately, I'm off line for a few days now but I'll look forward to your response.

I doubt realtivists have much of a problem with it. But this is the kind of thing that keeps me thinking about it over and over.

Me too - sends me to sleep thinking about it though :)

Everneo,

Still waiting for a reply to this very simple question. Remember?

"Get to the point and explain why one crew says "hey I've just picked up a message from a light beam that took me 100s on my stopwatch" and the other crew says "hey, but I travelled a bit faster and picked up the same message from the same light beam in a much faster / slower time on MY stopwatch". They compare notes and deduce that only one thing can be happening here - that the rockets were travelling at different speeds relative to the message and, hence, relative to the thing which is carrying the message (light)."

Don't go all quiet on me just because you're struggling to answer the question :bugeye:

I have already posted my answer. You want me to accept that c is variable? :bugeye:

I have already posted my answer. You want me to accept that c is variable? :bugeye:

All you said is that my premises are circular, that I am introducing a common time and that my thought experiments are odd, all of which are untrue and not addressing the reason as to why one rocket can collect the data faster that the other from the same beam of light.

Perhaps someone else can explain this very real scenario if Everneo fails to provide a satisfactory explanation.

Or is it easier for the relativists to simply ignore what could turn out to be the bitter truth?

Good news for you Dave, Look at the experiment below and do the follow up to my next posts about it in it.

<iframe src=http://sciforums.com/showthread.php?p=837886#post837886 height = 500 width= 700> </iframe> If this isn't a misuse of HTML tags, I know not what is.

Ho hum *dav57 awaits Everneo's detailed explanation* tum te tum

Read my first post.

If a light beam sent from a Planet A, has attached to it a simple message. Lets say the message is nothing more than a whole bunch of digits and lets say that the digits are separated equally and there are a total of one million released over a period of 100 seconds (all relative to Planet A). Don’t forget that the digits (or pulses) are separated by an equal number of whole waves of light and lets suppose that the light beam is of a single frequency to make life easy. Now then, Planet A has emitted this ray of light on the basis that the sol is the same to all observers and the aim of the experiment is simple: to establish if ALL recipients of the message respond with a verification message that they, indeed, received the one million pulses in EXACTLY 100 seconds. Only then can we verify that ALL observers are travelling at the same speed relative to the emitted signal from Planet A.

I’d like to consider the difference between two rockets, one stationary (Rocket 1) with respect to Planet A and one approaching Planet A (Rocket 2) at 0.9 the sol. From what I can see, Rocket 2 experiences a significant blue-shift of light and manages to collect the one million digits in a shorter period of time.

If Rocket 2 can manage to do this, then this to me indicates that Rocket 2 must have travelled past the beam of light faster than Rocket 1. There is a clear difference in experiences between Rocket 1 and 2 whilst taking measurements from the same source. This surely is conclusive evidence that the sol is not constant to all observers.
Hi dav,
You seem to be assuming that the length of the message beam is the same in the Rockets' rest frames... have you considered the possibilty that length of the beam is frame dependent? Unless you establish that question one way or the other, I don't think your experiment really determines anything.

To measure the speed of the beam in Rocket1's rest frame, I think you need to detect the beam in two places in that frame, and compare the time it takes for the beam to go fram one place to the other.


If you don't like the SI bases of length and time, perhaps you should go back to a base that you are happy with - such as the prototype standard Metre ("the distance, at 0°, between the axes of the two central lines marked on the bar of platinum-iridium kept at the BIPM, and declared Prototype of the meter by the 1st CGPM, this bar being subject to standard atmospheric pressure and supported on two cylinders of at least one centimeter diameter, symmetrically placed in the same horizontal plane at a distance of 571 mm from each other."), and the day standard second ("the fraction 1/86 400 of the mean solar day"). While these are generally considered less precise, they're still useful definitions.

Dav, Once you realise that all the predictions of SRT are premised on the invariance of light you will begin to understand just how impossible it is to refute SRT with out refuting the invariance factor.

It is easy to construct a reality around a fixed invariable by simply making everything else relative to that invariable, ie change the length , time etc....to accomodate an invariable.
IMO AE swapped absolute time for the absolute constant of lights speed to all observers. And to do this all he had to do was make length and time relative concepts as well. Thus lights sits in the middle of a relative to light universe....
So I would suggest that to save you heaps of circular reasoning come to realise that it is the invariance of light that is responsible for all of SRT's outcomes. And if you wish to refute SRT you refute invariance first.

No mean feat either I might add

Hi dav,
You seem to be assuming that the length of the message beam is the same in the Rockets' rest frames...

Yes, but regardless of this fact, each rocket "collects" the data at different rates and when they unite they compare notes to establish conclusively that there is a DIFFERENCE in the time it takes to collect the data from the SAME beam of light. Regardless of what else we throw into the argument, this is the fundamental fact. Introducing length contraction here is a kind of get-out-clause at the moment.

The way I see it, the rate at which the message enters the rockets changes due to the relative speeds of the rockets. The message is attached directly to the light beam, and this indicates that the rockets are travelling at different speeds relative to the light beam, albeit undetectable.

Dav, Once you realise that all the predictions of SRT are premised on the invariance of light you will begin to understand just how impossible it is to refute SRT with out refuting the invariance factor.

It is easy to construct a reality around a fixed invariable by simply making everything else relative to that invariable, ie change the length , time etc....to accomodate an invariable.
IMO AE swapped absolute time for the absolute constant of lights speed to all observers. And to do this all he had to do was make length and time relative concepts as well. Thus lights sits in the middle of a relative to light universe....
So I would suggest that to save you heaps of circular reasoning come to realise that it is the invariance of light that is responsible for all of SRT's outcomes. And if you wish to refute SRT you refute invariance first.

No mean feat either I might add

Yes, thanks QQ, I totallly agree. I'm desparately trying to do just that.

Have you thought about Machs principle and how it possibly dimensionalises the universe to zero. Thus making distances only relevant to intensity and not travel. Inertia being an absolute concept and not a relative one.....maybe
If inertia is an absolute then energy transfer is devoid of distance.....sort of thing

Yes, but regardless of this fact, each rocket "collects" the data at different rates and when they unite they compare notes to establish conclusively that there is a DIFFERENCE in the time it takes to collect the data from the SAME beam of light. Regardless of what else we throw into the argument, this is the fundamental fact.
Yes, but so what?
It's consistent with a frame invariant speed of light, if length is frame dependent.
It's not consistent with a frame invariant speed of light, if length is frame invariant.
Because you've left the question of the frame dependence of length open, your argument is inconclusive - your setup is not a reliable method of determining the speed of light.

Why don't you think about measuring the speed of light in a more direct way:
Put two detectors in each rocket, separated by a standard distance (such as copies of the metre prototype which used to be the SI standard).
Measure the time difference between the light beam being detected at each detector.

The way I see it, the rate at which the message enters the rockets changes due to the relative speeds of the rockets. The message is attached directly to the light beam, and this indicates that the rockets are travelling at different speeds relative to the light beam, albeit undetectable.

albeit undetectable... aren't you trying to show that it is, in fact, detectable? Why else would you say "This surely is conclusive evidence that the sol is not constant to all observers" ?
If it is truly undetectable, then I think it becomes a philosophical question whether the speed of light is frame invariant or not.

Consider this: It is possible to construct equivalent paradigms that give exactly the same predictions, and in such cases the choice of paradigm is one of convenience. For example, in Kip Thorne's book Black Holes and Time Warps, he describes using two paradigms of General Relativity - one in which rulers are bendy and space is fixed, and another in which rulers are fixed and space is bendy (See the book for details - my memory is fuzzy). Since it is not possible to determine which paradigm corresponds to the "true" reality, it is considered by some to be an "uninteresting question". By that point of view, it's the validity of the predictions that count, and boths paradigms are used, depending on which one is more convenient for a given problem. If, on the other hand, there is some way of distinguishing between the two paradigms (ie they give different predicitions), then the difference between them is no longer undetectable, and choosing between them becomes "interesting".

Personally, I think that the difference between functionally equivalent is an interesting question, but it's philosophical question rather than a scientific one.


Also, note that in the rest frame of Planet A, the Rockets are most definitely travelling at different speeds relative to the light beam... that's not what you mean, is it?

Why don't you think about measuring the speed of light in a more direct way:
Put two detectors in each rocket, separated by a standard distance (such as copies of the metre prototype which used to be the SI standard).
Measure the time difference between the light beam being detected at each detector.

Pete, this is a different type of experiment, isn't it?

I don't want to measure time differences between each rocket. I only want to measure the amount of time one rocket takes to collect the data. And then do the same experiment with another rocket that is travelling at some velocity relative to the beam.

I still maintain that each rocket takes a different amount of "proper time" (relative to the rocket itself) and thus conclude that there is a difference in realationship between the rocket and the beam depending on the speed of the rocket. This relationship is nothing less than the relative velocity between beam and rocket.

What else could it be???

albeit undetectable... aren't you trying to show that it is, in fact, detectable? Why else would you say "This surely is conclusive evidence that the sol is not constant to all observers" ?
If it is truly undetectable, then I think it becomes a philosophical question whether the speed of light is frame invariant or not.


Let me clarify by saying that I only thing the TRUE relative velocity between observer and a light beam is undetectable. I have stated my reason for this many times and I think it is a perfectly viable idea to take on board.

I have a thought experiment to demonstrate this and I'll post it soon. Bet you can't wait :D

Also, note that in the rest frame of Planet A, the Rockets are most definitely travelling at different speeds relative to the light beam... that's not what you mean, is it?

Well you've got me all confused now! But I suppose I mean THAT too. But I'm sticking to the original point, where we were discussing the relative velocity from the frame of reference of the rocket.

Well you've got me all confused now.
It is not that you are confused now. But you realised now that you have been confused all along. :p

It is not that you are confused now. But you realised now that you have been confused all along. :p

Nope, actually, I'm not confused. It's just that nobody has answered the question properly. You all know what I'm saying but you don't know how to answer it and you're too afraid to admit there is sonething unusual with my thought experiment.

You explain why each rocket collects the data at a different rate according to their reference frame, and I'll walk away more knowledgeable. Until then, your comments are meaningless and do nothing more than home in on your weak spots.

So I ask you again...why do the rockets collect the SAME data from the SAME beam of light in different amounts of their PROPER time?

because their PROPER times are different.

because their PROPER times are different.


But if the light travels at exactly the same rate towards an observer (as relativity claims) then a message attached to the beam would be measured EXACTLY the same, regardless of anything. This is clearly NOT the case and undermines the fundamental principles.

Your are right that the light travels at same velocity c for the moving rocket but the signal digits all are packed in the length contracted beam. The beam travels at c for the moving rocket but its length is contracted hence million digits it contains would be recieved faster by the moving rocket.

Pete, this is a different type of experiment, isn't it?

I don't want to measure time differences between each rocket. I only want to measure the amount of time one rocket takes to collect the data. And then do the same experiment with another rocket that is travelling at some velocity relative to the beam.
Sorry, perhaps I wasn't clear. See the following post for an example of what I meant.

I still maintain that each rocket takes a different amount of "proper time" (relative to the rocket itself) and thus conclude that there is a difference in realationship between the rocket and the beam depending on the speed of the rocket.
Agreed
This relationship is nothing less than the relative velocity between beam and rocket.
What else could it be???

The relationship is the product of the length of the beam in the rocket's rest frame and the relative velocity between beam and rocket.

You want to assume that the length of the beam is the same in the rest frame of both rockets... but how do you know that assumption is valid?

Let me clarify by saying that I only thing the TRUE relative velocity between observer and a light beam is undetectable. I have stated my reason for this many times and I think it is a perfectly viable idea to take on board.
Assuming for the moment that you're right, this falls into the realm of philosophy, like I said before. Interesting... but not really useful.

But as it happens, I don't think you're right.
I think the problem with your idea is that you haven't considered ways of measuring the speed of light without using light as the calibration tool.

For example:

Let's say you and I have identical walking speeds (or we could substitute identical robots if you like).
Let's say we also have a long straight hall with identical clocks and detectors at each end, set up to that when a detector is triggered, the time on the clock at that end is recorded.

We find the middle of the hall by pacing it out - eg if the hall were 1000 steps long, the middle would be 500 steps from either end.
Starting in the middle, we walk to opposite ends and set the clocks to zero (reality check - do you agree that the clocks are synchronized?)

A signal flashes along the hall, triggering the two detectors. (The signal could be anything, including but not limited to a light beam).

We both walk to each end, and look at the recorded times.

If
time = the difference between the recorded times, and
length = the distance between the detectors (the length of the hall)

do you agree that the velocity of the beam relative to the hall is simply and unambiguously length / time?

do you agree that the velocity of the beam relative to the hall is simply and unambiguously length / time?

Errm, yes, and...

Good!

Do you see that this method of determining the velocity of the beam gets around your objection:

I have previously put forward the notion that light only APPEARS to travel at a constant speed due to the limitations of our measuring equipment, i.e. we are attempting to measure the speed of light USING light, and this has a serious consequence as to our interpretation of what we are measuring as opposed to what is REALLY happening.

Good!

Do you see that this method of determining the velocity of the beam gets around your objection:


I don't know what I think, but I know I don't like length contraction!
It still seems like a get out clause.

I'll think some more...