i've started this thread as a carry on from another thread.

it entailed a short exchange between myself and Tim Thompson on the subject of time dilation and lorentzian contractions/rotations.

in that discussion Tim stated that the twins paradox was not an example of time dilation.

regardless of that opinion/position, the twins paradox was formulated many years ago as an example of time dilation...which had previously been expressed as the clock paradox by einstein.

and although Tim wishes not to call it time dilation....still the same parameters are involved and the same results obtained eg: 2 clocks (or twins) with 2 separate and distinct spacetime lines that are at odds with each other...hence the paradox.


so i've started this thread to again address the concern i have with these relativistic effects.

this is unrelated to mathematics...focusing on what i believe is a crucial problem.
ie: "how the data is applied".

i propose that these relativistic exercises should never devolve into paradoxes...at least not to the extent that they cause conflict with real spacetime....and that they are simply optical illusions...and should be treated as such....nothing more or less.


in the following sections i put forward an argument as to why i think there is no real paradox involved in time dilation...and also comment on a few associated points.

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to achieve time dilation, we need data...which is supplied by light, travelling at velocity c.

we also require an observer (or detector if it's gps) to receive the light/data....and something to observe (say "the observee", who will transmit the light/data).

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nb: light takes time to travel..the further the distance, the longer the time.

if the distance is further increased between observer and observee, then the light signal becomes further delayed as well, simply because it has further to travel from the emission point to the detection point.

at relativistic speeds (which produce great distances) the delay can become substantial.

nbesp: this is the reason why the following exercise in "spacetime paradox" can occur...and also why it takes a particular formularisation involving time.

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in the twins paradox, one twin is stationary and the other travels away at a relativistic speed.

the observer (for this example) is the stationary twin, who observes the travelling twin.
and to actually do this, the observer must receive data from the observee...which again is provided via the "light signal" (the rarely mentioned mechanism for the act of observance).

so what is the natural product of this scenario?


due to the increasing distance between the twins (approaching several light years over time)...the light signal sent from the travelling twin becomes increasingly delayed...simply because it is emitted at increasingly further distances and therefore takes "longer and longer" to travel to the stationary twin, as time goes by.

....so eventually the stationary twin can find himself receiving data that is years out of date....and therefore be able to experience a paradox involving time.

in the twins paradox this is applied to the concept of age difference displayed by the 2 sets of data held by the observer..ie: his own age and the age of the travelling twin seen in the received data.

the data conflicts of course...the travelling twin looks like he has aged less than the stationary twin....but this is just because the data is old....so is this acknowledged?

no.
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the observer and data are bundled together under the term "reference frame"...SR predisposes our decision processes to accept any reference frame in the exercise (with whatever data it holds) as valid...so the fact that the data held by the observer is old, is forgotten...and that data is plugged straight into spacetime theory immediately causing an aberrant space-timeline (projected for the travelling twin...by the stationary twin).

the same conditions (and pre-disposition) also relate to the travelling twin, resulting in the same product type.
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the pre-disposition relates back to SR

SR is based on the "inertial reference frame" (IRF).
the aspect of the IRF that makes it "special" is the aquisition of a state of uncertainty.

uncertainty as to time/place/velocity etc relative to other IRFs.

therefore in this state...all IRFs may seem valid...but this is a very special state, that can only be achieved if there are no clues to help you out of the predicament.

in time dilation we do have clues....we know the signal has been delayed and we know the reason why....just like we know that the sun's image is really 8 minutes old...and precisely why it is "observed to be that way".

we do not have to suspend reason and demand illusions to be temporal facts....just like we don't demand that the true age of the sun is exactly the age we observe it to be.

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both time dilation and lorentzian contractions/rotations are dependent on travel time of light...from observee to observer.
these exercises cannot function without these parameters.


time dilation is the result of imposing out of date data upon the universe

lorentzian contractions are the result of imposing 2d motion blur upon the universe
lorentzian rotations are the result of imposing 3d motion/fov distortions upon the universe


they are all observer based illusions that are allowed to bypass reality checks and run amok on reality.

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also...since time dilation and lorentzian contractions/rotations are solely observer based illusions...they therefore cannot be measured in-situ.

any variance in rates of eg: atomic clocks flown on planes in comparison to stationary clocks...is a separate physical process totally unrelated to time dilation.

combining this effect with time dilation only confuses the issue...generating an inappropriately derived "proof"....and promulgating an incorrect belief that time dilation produces real physical alterations.

it does not...and cannot. (Tim in fact stressed this point in the other thread too).

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the same for muons.

muon half-lifes only last for 2.2 microseconds when the muons are kept at rest or at a very low speed.

muons travelling at relativistic speeds in an accelerator ring (or through the atmosphere) last a lot longer.


http://www.er.doe.gov/Sub/Newsroom/N...IN_PARADOX.htm



"At rest, or moving very slowly compared with the speed of light, the muon decays into an electron and two other particles, known as neutrinos, typically in 2.2 microseconds."

how far might these types of muons travel then?
"2.2 microseconds multiplied by 300,000 km/second = 0.66 km"

(nb: the above is a quote from the article...but it implies a conflicting situation of having a muon "at rest", yet travelling at speed c so we can measure it's travel distance vs halflife...this is really a fantasy extrapolation applied to an unnatural muon state (ie: kept at rest) and is also the root of the incorrect prescription that muons need time dilation to travel through our atmosphere)


"Muons are created in the upper atmosphere, roughly 10 kilometers above the surface of the Earth, when cosmic rays collide with the atoms in the atmosphere. Muons can subsequently be detected at the surface of the Earth, or even as much as 1 kilometer below the surface."

"Muons can be produced in the laboratory through the same types of collision as take place in the upper atmosphere. Because they are charged, we can steer them into circular storage rings, and keep them going round and round at speeds exceedingly close to the speed of light, say 0.995 c. In experiments at laboratories in both Europe and the United States, such muons have been found to survive typically for 30 times the 2.2 microsecond lifetime before decaying"

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muons need to travel at least 11 kms to get from the atmosphere to 1km below the surface of the earth...is this possible?

30 * 0.66km = 19.8km

yes...when created and/or maintained in their natural state (travelling at velocities close to c) their lifetimes are longer...so they can get from the atmosphere to the earth with kms to spare.

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one set of data points to a halflife of 2.2 microseconds for muons (when at rest or low speeds).

2 sets of data point to a halflife of upwards of 66 microseconds for muons (when travelling at relativistic speeds in an accelerator ring..or through the atmosphere).

muons therefore do not appear to require time dilation to travel from the atmosphere to the earth.



even if time dilation were applied (to an "at rest" type muon...allowed to travel at c....but retaining it's 2.2 microsecond life), the observer would still only see the muon travel 0.66km...but take upwards of 66 microseconds to do it.

and really...to even be able to achieve this as a "time stretching" would require the muon to travel away from the observer...otherwise there can be no paradoxical "stretching of time", which is reliant on the "light travel time to the observer" getting longer...a parameter that is directly effected by "distance".

muons approaching the observer would be time-condensed and have shorter lives...or "age faster"...just like a travelling twin on the return leg of his relativistic trip...seems to the observer.

for time dilation to come anywhere near being an explanation for why muons can travel from the atmosphere to the ground would first require an observer sitting up in the atmosphere directly above the creation point of the muon...so they can watch it travel directly away from them and towards the earth....and still it wouldn't work because the muon will still only travel 0.66km....regardless of how long it seems to take for the observer.

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another point in regards to this business of muons needing time dilation to reach earth.

where are all the observers that are required to achieve this?

who is watching this illusion?

[paraphrase]if a muon is created in the atmosphere and there is no observer to time dilate it..does it still not reach the earth?[/paraphrase]

ISn't time dilation taken into account by GPS?

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'The eye can only see what the mind is prepared to accept'

Particle physicists observe this 'illusion' on a daily basis. Particles at rest in a lab facility decay in less time [according to clocks in the same inertial rest frame] than their accelerated brethren. This has been experimentally confirmed on a daily basis for decades.

Maybe it would be better if madman would order his message a little and describe what he does not like about time dilation.
And naturally the problem with a paradox is that it is a paradox.

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Optimism does not change the laws of physics. (T'Pol)
A good scientist has freed himself of concepts and keeps his mind open to what is. (Dao De Jing 27)
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Martin ( http://www.geocities.com/DrMartinV )

Yes. It's not a separate mechanical/physical process. Note that there is a combination of gravitational and kinetic effects.

I've read that when the first GPS-related satellite was flown, there was some doubt (among the beancounters, presumably, and not the physicists) that any correction would be necessary, so the clocks were synchronized on the gotund, with the ability to tune an oscillator onboard. The satellite was launched, lo and behold, it was running at the wrong rate. The synthesizer frequency was changes to the preset value, and the clock output was then correct to 1%.

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"I have a cunning plan that cannot fail."
S. Baldrick

The reason I don't like the usual time dilation explanations is that they make it too easy to confuse coordinate time with proper time. Coordinate time is the time coordinate, that goes along with the space coordinates, to make up the spacetime coordinates for an event (x,y,z,t). The coordinate time depends on the observer, as do all of the spacetime coordinates for any event. So, for any given event, there are as many different coordinate times associated with it as there are observers.

But there is only one proper time for a given event, and that is the time ticked off by a clock in the rest frame of the event. That time, as observed by an observer at rest with respect to the clock, never dilates, whatever anyone else might see or think.

We see the muons falling through the atmosphere, and we see "time dilation", the muon lives longer in our reference frame. But the muon does not see it that way. It's too easy to think of time dilation as "real", not in the sense that we see it, but that it somehow means more than what any other observer would see. I call it an illusion, because it is entirely dependent on the observer reference frame, which is not the case for proper time.

Tim
i agree...but the illusion is still the core result that is promoted for time dilation.

ie: that the observed twin will physically age less than the observing twin.

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the original exercise was roughly handled...contemplating only the basic step of increasing the distance between the clocks or twins and therefore creating a delayed transmission.

ie: any x,y,z vector away from the observer can be collapsed into a single value pertaining to distance only....and light takes time to travel over distance.

if a travelling twin is 1 light year away...it will take a year for the message to reach the observer....but we are forced to forget that this information is a year out of date....and to take it as a fact that what the observer sees is the true age of the travelling twin.


at first this was extrapolated to allow the travelling twin to return to earth younger than the stationary twin.

later the "return leg of the journey" was contemplated and so a "time condensation" (fast aging) had to be included in the consideration.

this messed things up a bit with the previously held concept that simply travelling at relativistic speeds produced a slowing of time.

and drew attention back to the fact that this is only an observer based illusion....it is not a physical alteration of the travelling twin.


the effect is shown to be solely a frequency dilation of the transmission....due only to the alteration of distance between emitter and receiver.

this is also why we ended up with doppler spacetime diagrams.

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you mention "proper time of a frame"...and the ability of another frame to be at rest in regards to it..and therefore experience no time dilation effect from the first frame.

again i agree.

also i can agree that similar time speeds can be achieved by similar entities/bodies in similar energetic environments.....so that eg: 2 atomic clocks will tick at the same rate under the same conditions.

but any frame at rest with respect to another frame is still separated by distance....so whatever one frame can know about another frame still relies on the travel time of light between them.

the only difference between this scenario and the twins paradox is there is no extra motion occuring that alters that distance (therefore the reason for no dilation).

so the 2 frames at rest with respect to each other will still experience a transmission delay of light...but this would not alter it's form...and would be similar to the transmission delay between the sun and the earth.
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Madman. I believe you missed a key point in the twins paradox. The situation is not symmetrical. One twin remains "home" at rest. The other accelerates to a high velocity....travels at constant velocity for an extended period of time.....accelerates in a turn 180 degrees.....travels back same distance...and then must decelerate to meet his/her brother/sister in the original reference frame. The kinematics are not symmetrical, and the consequences of the asymmetry in their experienced forces is intimately involved in real time dilation. Try Max Born's paperback book "The Special Theory of Relativity" by Dover books....gives the entire turn of the century treatise in a very lucid manner....including the almost never mentioned....transverse Doppler shift. Ciao. Pete.

I think most treatments of the twin paradox assume that one twin is already moving - the first acceleration you mentioned isn't considered, only the turnaround.

__________________
"I have a cunning plan that cannot fail."
S. Baldrick

madman,

Your analysis of the twin paradox is much too complex. All you need is two twins with synchronized watches. One twin remains home while the other leaves. When the other twin returns they compare watches and the twin who was away finds that his watch has lost time. In the many variations on the theme, acceleration is the one thing that breaks the symmetry. The twin who left home experienced a greater amount of acceleration than the twin who remained behind. He may have traveled to Alpha Centari and back or he may have been in the next room sitting next to a black hole. In one case the acceleration is inertial and in the other it is gravitational but acceleration is acceleration (Einstein’s equivalency principle) and acceleration slows time.

That's true, but the muon does see the distance between upper atmosphere and ground as much shorter than we measure it, which is how it's able to travel from one to the other in the much shorter time measured by its own internal clock. Whether you think of the muon as travelling 10 km in 66 microseconds, or 0.33 km in 2.2 microseconds depends on whether you choose to measure the behavior in the "lab" frame or in the muon's rest frame, and both (as well as any others you might decide to use) are equally valid.

Time dilation and length contraction are thought of as "real" in the sense that measurements of time and space depend on your relative motion. But of course if you're moving along with a clock or a meter stick, they're at rest relative to you, so you'll never see them appear to do anything unusual regardless of how you (along with your clock and meter stick) might be moving relative to other things in the universe.

many examples argue over how and when the "effects" of SR are applicable...ie:

does it hold in an accelerating or non-accelerating frame?

does the turnaround at the middle of the twin's journey collapse the state so the relativistic effects aren't felt?..etc

it doesn't matter


since the whole operation revolves around light and it's transmission...all frames (supposed emitters/receivers) in the exercise would be viable.

in fact they will all express whatever "time dilation" and/or transmission delay effects that apply between them.....regardless of whether they have the "right stuff" for SR or not.

and remember...these are exactly the same "special effects" that you're only supposed to be able to get with SR.

ie: the data that any observee sends to any observer is still a frequency dilated signal (time dilated when moving away...time condensed when approaching)...and is also delayed by the travel time/distance (giving the age difference effect).

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achieving the requisites according to SR (so that it's the "real time dilation")...is then really an exercise in forming a sub-group from a larger group, who all express the same function.

and there can be nothing special about a function if all members of the group express it by default!


so the only thing SR seems to do in this "selection" part of the scenario...is to apply some arbitrary rules to ignore a portion of the group.

ie: "this particular observee hasn't got the right stuff for SR...so i'll ignore his frequency dilated and delayed signal..and say it doesn't exist".

"this part of the observee's activities hasn't got the right stuff for SR...so i'll ignore just this bit..and say it doesn't exist".

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so...to repeat.
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all observees in the exercise will exhibit whatever "transmission delay" and "doppler shift" effects applicable...due to their relative distances and velocities.

all observers will see these effects....resulting in "received data" that seemingly exhibits an age difference (due to distance)....and fast or slow time (due to relative velocity).

and all observees and observers will do this naturally in spite of SR.

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but "transmission delayed" and "doppler shifted" light, does not a paradox make...when you are aware of the facts.

and so this is where SR is needed to again apply that "special" twist on the exercise.

the great enablement that it once again brings is the ability to forget those very facts.

so that you may believe:

1) that the age seen by the observer is the true age of the observee...(by forgetting that the message took years to travel to him).

2) that the slowed time speed seen...is the real time speed the observee is experiencing...(by forgetting that the relative velocity doppler shifts the signal).

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Q) so how do we really enable this SR approved function?

A) via the reference frame.


data held by a reference frame (see observer) needs no reality check regarding it's meaning or applicability.

it can be punched straight into spacetime theory and damn the consequences.

in fact (if it's got the right stuff for SR) it must be imposed upon the universe.

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thus the product? (and only for those very special cases where SR approves):

"seeing is believing" (because with an SR reference frame...you bypass all reality checks!)

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so, in conclusion:

the very special quality that SR brings to this exercise is ignorance...so that an arbitrarily selected sub-group of optical illusions may be imposed upon the universe as facts.

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You seem to be under the impression that transmission delay and Doppler effects are neglected in special relativity, which is not the case. You also seem to be under the impression that these effects could account for the observations. That's also not the case. Special relativity predicts additional effects beyond those expected from Doppler shifts and the delay in light travel time, and those additional effects are borne out by experiment.

As said THANATOS the time dilation it is the experimental fact (#3). When particles are moving faster then live longer. The real problem is why they live longer. I think that problem is because we are talking too much about the mathematics, not about the physical meaning of this effect.
A space is more curved when the energy density has higher gradient i.e. has higher the energy density drop. It means that the more powerful vortices (cyclones) give the more curved spaces. In such space we can move between two points, for example equidistant of the centre of a vortex, only along an arc. If the curvature is higher then the path is longer and a light needs longer time to reach the second point. It is dilation of time. As said Einstein, in spaces of higher gravitational field intensity dilation of time is also higher. When we accelerate some object then the angular velocity increases (the object rotates more quick) – it means that there is created stronger vortex and it means that in such object time is going slower i.e. the separation of particles in the decay, for example, of the muon last longer because the particles are moving along the more curved trajectories.
What about the twin paradox. The Einstein special theory of relativity and the Bohr quantum mechanics are correct but incomplete. This incompleteness was the source of permanent quarrels between these genius scientists. Einstein to the end of his life did not understand his statement that light has speed “c” in relation to all objects in space (true) simultaneously (false) (see #26, thread ‘Before the Big Bang’). The assumption that the Universe is built of one component only, i.e. the neutrinos leads to the wrong interpretation of the relativity theory. The existence of the quantum mechanics proves that there must be at least one component which moves with the velocity much greater than the light velocity in vacuum because from the quantum mechanics results that in our World there do not exist systems separated spatially. How one should interpret the relativity of time or relativity of the clock rate? Imagine that in the whole Universe there exists only one spherical object and connected with it the set of the eterion-higgson streams. At certain moment the object explodes and decays on two identical parts. We know that the velocity of each part in relation to the other is the same. In which part the time goes slower? Of course the time goes in both parts the same because we have here a perfect symmetry. Now we can explain the twin paradox. Twin brother who moves in rocket in relation to the eterion-higgson streams connected with our Earth will live longer because this streams are stronger than created by rocket.

Gamma

i was going to write a long post to detail some points...but instead thought i'd just focus on the gist of the argument first.

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many of you will know about the concept of the "light clock" and how einstein uses it to formulate a value for gamma.




2 mirrors (separated by some distance) face each other.
a pulse of light is sent directly from the first mirror (at bottom) towards the second mirror (at top).
upon arrival the light pulse reflects from the second mirror and travels directly back to the first mirror.
the operation continues indefinately, undergoing no change in parameters and taking the same amount of time for each leg of the journey.
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but einstein then assumes (without proof) that the light will travel from one mirror to the other in the same amount of time regardless of whether the clock is still or in motion.


here is his assumption.



nb: i've set the horizontal velocity of the mirrors equal to C simply for clarity (it could be any fraction of C).
the vertical motion is the unit measurement einstein assumes will remain constant.

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i have simulated this experiment on a computer and found that the result shown above does not occur.

it is a fantasy of einstein...the result of either false expectations or mistaken assumptions.


here is the reality.



as you can see...movement of the mirrors has no effect upon the light pulse...which continues it's predetermined journey at speed C.

but now instead, there is no mirror to reflect from when it arrives.
because in effect, the mirror has "dodged the bullet".

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this immediately shows that something is wrong with einstein's "thought experiment".
if the light pulse is operating like a bullet?, then we would actually need to aim it at a point the mirror will occupy sometime in the future.

this brings to mind the concept of an "interception course"...yet einstein believes this to be "a given" in his scenario?

and what if we do aim the light pulse at the correct interception coordinates?


again...here's the reality.




the light pulse can't reach the mirror since the diagonal distance is always longer than the vertical distance (or unit time allowable).

and that situation was directly caused by altering the coordinates of the 2nd mirror and thereby increasing the real physical distance.

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another way of showing the distance that light can travel in this exercise is by modelling it as a wave.

this negates the problem of interception, since the wave will travel in all directions.

but still it can't reach the mirror in the unit amount of time.




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conclusion:

einstein is wrong.

gamma cannot be formulated because his assumptions are false.

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nb: although the data has been displayed in a simple animated gif format..each frame may be regarded as a sample point from a continuous simulation.

the simulation is based on simple yet accurate calculations..and the results are displayed with pixel accuracy.
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I think you have a misconception here, my dear madman.
With your reasoning you could look at a train passing by and no one in the train would be able to bounce a pingpongball on a bat, which for the person in the train would just go straight up and down, whereas for someone outside the train it would go in a "zigzag".

__________________
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Optimism does not change the laws of physics. (T'Pol)
A good scientist has freed himself of concepts and keeps his mind open to what is. (Dao De Jing 27)
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Martin ( http://www.geocities.com/DrMartinV )

If both of mirrors are moving then the space between them is changed. A high velocity makes a length contraction and the light will reach a second mirror.