Simple Relativity

[Ver]

I have a geometric view of SR which gives the correct answers to simple SR time dilation calculations. I am told my method is incorrect with statements like "thats not how it is" or "A reletavist would not agree". I would like to know precisely at what point it deviates from logic.

Take three photons from an event in a gravity free area of space. Two are heading in opposite directions,each on the precise reciprocal of the other while the third heads out at 90 degrees to the line formed by the reciprocals.

During propagation I place a small object on the reciprocal headings of the three photons and hold it there for a short duration. Letting the object go, it now becomes inertial and will stay on the reciprocal of the three photons.

Is it fair to say the object marks the origin point of the photons and the three photons are moving at c from that marker therefore the object is at an absolute with regards to c.

If the three photons were reflected back on the reciprocals would they all strike the object and in fact impart energy to electrons within the object.

Does the event have no relevance to the frame on which the event was created other than the frame must be within the sphere of propagation, ie photon speed is indepedent of the frame speed.

Would a similar marked event precisely one meter from the first leave two inertial objects staying one meter apart irrespective of the frame speed and direction of the frames which created the events.

Would synchronised clocks placed at the two markers always read the same time.

This will probably be as far as I can go before being corrected.

[sigurdV]

:)

[sigurdV]

It seems you have been ignored by explanators of Physics. Probably an oversight. I think I understand your setup and think there should be answers to your questions:)

[Ver]

It seems you have been ignored by explanators of Physics. Probably an oversight. I think I understand your setup and think there should be answers to your questions:)

Hi SigurdV

I have not been active here for a while. Thanks for your comments. It is interesting how relativity has developed since the arrival of Lorentz. and the acceptance of his theory which works when you subtract from the Aether its mechanical and from matter its electromechanical properties.

If Maxwell or his "followers" had succeeded in elaborating a mechanical model of relativity at the same time as that of Lorentz, which theory would have been accepted?.

From the time concensus agreed with Lorentz, any mechanical theory is disregarded, not by the parameters which would have made a mechanical theory acceptable but by using Lorentz to prove the mechanical theory is incorrect.

I think I need to know what were the parameters that Maxwell and others were not able to satisfy so I can then satisfy myself that I have failed.

[CraigD]

I have a geometric view of SR which gives the correct answers to simple SR time dilation calculations. I am told my method is incorrect with statements like "thats not how it is" or "A reletavist would not agree". I would like to know precisely at what point it deviates from logic.

The derivation of Special Relativistic time dilation is a simple geometric one, based on ordinary Euclidean geometry and SR’s postulate that the vacuum speed of light is constant, so I’ve no reason to suspect your view isn’t right, and essentially the same as the usual derivation (see wikipedia’s “Simple inference of time dilation due to relative velocity” for an example).

 

Post your derivation (“answers”) here – the style of the Wikipedia section is a good style guide – and we can confirm that this is the case, or point out where a mistake is made.

 

I wouldn’t pay much attention to statement like “that’s not how it is” or “a relativist wouldn’t agree”. Mathematical physics is a formal, not philosophical or sociological discipline.

 

Take three photons from an event in a gravity free area of space.

I don’t understand what you’ve written here.

 

I think a sketch would help.

[Ver]

Hi Craig

Take three photons from an event in a gravity free area of space.

I think there is a bit missed here. It should be--

Take three photons from an event in a gravity free area of space. Two are heading in opposite directions,each on the precise reciprocal of the other while the third heads out at 90 degrees to the line formed by the reciprocals.

 

I am trying to illustrate my belief that all photons originated from that marked event. Disregard all the other photons on the edge of the event sphere and just work with these three for simplicity. The frame which created the event can be anywhere within the sphere therefore the photons are not frame dependent like the event marker. For me c is the absolute here and so is that point between two opposite heading photons, I dont believe a moving frame observer can indicate the location of his event point after some propagation even if Lorentz is sure he can.

I understand Maxwell and others tried and failed but what were the parameters on which he failed? If my straw man is to be knocked over perhaps it should be by those same parameters.

[sigurdV]

 

Take three photons from an event in a gravity free area of space. Two are heading in opposite directions,each on the precise reciprocal of the other while the third heads out at 90 degrees to the line formed by the reciprocals.

 

Disregard all the other photons on the edge of the event sphere. The frame which created the event can be anywhere within the sphere therefore the photons are not frame dependent like the event marker.

.

The three photons (xyz) constitituting a frame with its origin in the event (e). (Right so far?)

[Ver]

The three photons (xyz) constitituting a frame with its origin in the event (e). (Right so far?)

Ok

Lets use the sphere in a particular way.

From this same event we have a moving frame heading in the same direction as one photon at .6c.

The event occured at the left hand side of a tabletop the surface of which is flat face to the direction of travel.

There is a single photon crossing the table top from that event. The frames observer is measuring the speed of the tabletop crossing photon.

We are observing this from the perfect and absolute symetry of the sphere.

We can draw this precisely.

Draw a circle 100mm radius.

Draw in a vertical line from the compass point up through the circle and mark a point 6cm up from that point.

this 6cm point represents the point at which the tabletop is at .6c compared with the photon heading in the same direction.

draw a line out at right angles to the right, from this point and right out through the circle. The intersection with the circle represents where a single photon is.

Draw a line from the center of the circle to the intersection point. This is the path of a photon from the event to the tabletop

Now observe- the frame speed was .6c The intersecting photon has moved from its event at c, this is the tabletop crossing

photon. It has moved over the tabletop .8cm. The time dilation for that frame is .8 time.

Draw this at various scales and we see at that frame speed, it is always the same photon progressing over the tabletop.

I am saying here that the frame observer can only measure the crossing speed at c but looking at the sphere we see the photon is not crossing the tabletop but constantly intersecting it with that intersection progressing at less than c while it is actualy moving at c from its event, which the moving frame has no option but to leave behind. It did not start where the observer in the frame thinks it did.

Back check this by saying to the moving frame observer, create a marker event at the left hand side of the tabletop to indicate where you believe the photon started from after it has progressed any amount. Observe from the absolute of the sphere if he is correct. He misses the marked event point each time.

[sigurdV]

I have trouble understanding the continuation...

 

Two perhaps stupid questions:

 

What is a table top doing there in outer space,

and can frames move six times faster than light?

 

Things like end points of a diameter of our universe should through expansion have a relative speed exceeding that of light ... but Frames?

[CraigD]

Ok

Lets use the sphere in a particular way.

From this same event we have a moving frame heading in the same direction as one photon at .6c.

The event occured at the left hand side of a tabletop the surface of which is flat face to the direction of travel.

There is a single photon crossing the table top from that event. The frames observer is measuring the speed of the tabletop crossing photon.

We are observing this from the perfect and absolute symetry of the sphere.

We can draw this precisely.

Draw a circle 100mm radius.

...

Ah, I believe I see what you’re up to, Ver.

 

Sketching what you describe, I get this:

 

The equation for a unit (radius=1) circle is [math]x^2+y^2=1[/math],

which can be manipulated to give [math]x = \sqrt{1-y^2}[/math],

and is essentially the same as the usual time dilation formula [math]\frac{t_s}{t_f} = \sqrt{1-v^2}[/math],

where speed v is in units of the vacuum speed of light.

 

So your geometric construction give the same result as the usual formula. :thumbs_up

 

Strictly speaking, it’s not a derivation of the formula from first principles and postulates the way the light/mirror clock example I linked to in my previous post is, because you’re not describing things that can actually be measured, such as the arrival time of a light pulse at a detector, but it’s a good visual aid, intuitively showing the “not much time dilation happens until the slow-ticking observer get close to c relative to the fast ticking one” nature of the equation clearly.

 

This certainly is the way special relativity works.

[Ver]

Ah, I believe I see what you’re up to, Ver.

 

Sketching what you describe, I get this:

 

 

Hi Craig

Thanks for your answer and the thumbs up for part of it.

Your diagram is almost there. A line from the center of the circle to the tabletop intersection with the sphere should be considered.

If we look at the initial formation of the sphere by photons eminating from the center of it and describing the spheres radius at all positions.

Each radius is precisely the same as any other and its origin is the same as any other. We have now drawn in one radius and there is one photon at the surface of the tabletop, on the intersection with the sphere. This has all happened in a sphere of 20cm and we can see where the left hand side of the tabletop is now. Lorentz would tell us it is where the tabletop crossing photon started from. We are observing from the symetry of the only absolute in the universe and we know where the photon started from. Does it cross at c-- no because it is intersecting the tabletop and that intersecting speed is less than c. Is it moving at c, yes, just like any other in the sphere.

 

How about the light mirror clock then. Lets back check it. Propagate the sphere to 20cm and use the moving frame mirrors, continue frame movement till the reflection again returns to the frame--Does that prove anything. If the frame observer creates a marker event at the start point on the tabletop the moment any part of the sphere starts to propagate He has missed the absolute center of the sphere. Every marker from his frame will miss the absolute target. The frame observer is only convinced by the reflection and not by the absolute of the propagation.

 

Photons are detectable packets of energy moving at the absolute of c so what is that point between two opposite heading photons from the same event marked by a third photon if you wish, moving at right angles to that line and from the same event.

 

Retain the tabletop start point at the above example point and use the sphere. The tabletop crossing photon can now cross at c, it is not intersecting so what is the time dilation, absolutely nothing. So how fast is the frames clock going-- absolute time- or as fast as any other similar example in the universe. Can these clocks ever meet, no. Absolute rest works for me even if at present, it cannot be detected.

[Ver]

I have trouble understanding the continuation...

 

What is a table top doing there in outer space,

and can frames move six times faster than light?

 

Things like end points of a diameter of our universe should through expansion have a relative speed exceeding that of light ... but Frames?

Hi Sigurd

---- Remember these are purely my views of relativity.---

Well the tabletop is used for an experiment within the moving frame to measure the speed of light in that frame. It was moved up there for convenience.-- the frame can be a space vehicle or even just the table but everything moving with that table is what I understand to be a "frame".

Look at the following diagram and the tabletop which is represented by the horizontal line, so we are looking at the edge of the table. The tabletop is moving up the sphere vertical line the flat face of the top- moving in the direction of travel,so the sphere has propagated say 10cm radius which is made by photons moving at c, therefore the tabletop moving at say .6c has only moved up that line 6cm. The photon crossing the tabletop is the same as any other in the sphere moving from the center of the sphere at c. Mark in the extra line from the center of the sphere to the intersection on the tabletop for extra clarity.

There is another "Frame" in the diagram and that is the sphere. It is not moving with the tabletop.

Can frames move 6 times the speed of light. No for sure. It is probably the way I wrote it but it should read .6c (point six c)

[sigurdV]

Thanx! Its nice when things get explained!

 

I will not stop reading your thread, your introductory statement caught my interest.

But since im new to SR my progress will be slow... also i should fit in some reading on Maxwells theory,

Ahem I mean checking out anscient Physics up to Newton and Maxwell.

 

(to be edited)

 

Abstraction. (Abstraction"Exemplification)

 

1 c="The speed of light

2 energy (Heat Light Resistance to gravity Inertia)

3 frames (Up to tabletops)

4 events (Aha! .6 not = 6)

5 distance (Pythagoras?)

6 photon = "packet of energy" (Vibrations up to Planck.)

7 location presence and heading

Brb

 

A Geometrical model of special relativity a "heavy" thought experiment.

[Ver]

A question in the last paragraph.

This is a rehash of my first post and I hope this makes it clearer.

The only absolute in the universe is c, so how about a geometrical exercise based on that and check it out against Special Relativity in a particular way. Look at the sketch and consider it to be photons moving from a pinpoint event in gravity free space and having formed a perfect sphere. This can be drawn to scale. 200mm sphere works fine for A4. All photons have moved at c and have moved precisely the same amount. Each and every one has formed a radius of the sphere and has moved in a straight line to the spheres edge. This is not formed from a light beam or even a pulse of light, therefore there is not a "stream" of photons, just single photons. I believe we can say each photon is a small identifiable packet of energy which has a location and a presence and heading. Our frame is that of the event, we are inertialy co located at the event.

In this frame observe the position of the tabletop which has moved from the event in the direction of the vertical radius (heading) photon. The left hand side of the tabletop was lined up next to the event precisely at the moment the event was created. The tabletop moved at .6c flat surface in the direction of travel. We can see the tabletop edge out to the right as a horizontal line the tabletop moving at .6c has moved up the directional line 6cm and now intersects the sphere. The directional line represents c and is 10cm long like all the others in the sphere. We can see a photon at the surface of the tabletop intersection. This photon has moved from the event to this position, precisely the same amount as any other photon in the sphere. This photon having marked a radius of the sphere is moving at c just like all the others.

We stay with the frame of the event--sphere and observe the photon carefully. Re create the event and allow 1cm propagation, the table will then have moved up 6mm and there is a photon at the surface of the tabletop. It is the same photon, at any scale, (gradually increase the size of the sphere) it will always be the same photon until it has totally crossed the tabletop.

My observation here is that the photon is not crossing the tabletop but it is constantly intersecting the tabletop and the crossing speed of the intersection is .8c and not c. Yes the photon is moving at c, from its event, just like all the others. Draw it out and check the crossing distance, it will be 8cm. Now check out the time dilation for the tabletop. If the photon intersects at .8c, then time itself for the frame of the table will be .8time. Check that out with the correct formula. Any journey made at .6c has a base journey time of light years divided by .6 and the frames clock has no option but to run at .8 of that journey time so the correct time dilation is no problem.

Ask the observer with the table to point where the photon started from. He will point to the start point of the experiment at the left hand side of the tabletop. Now ask the observer, located at the sphere or absolute frame and ask if he was correct, "No he missed". Lets try again, This time the tabletop observer is asked to create a marker event at any time to indicate where he believes the photon started from. Every time he tries he misses. Try an exercise with mirrors, for sure the reflection returns to the moving frame, but, that is just it, a reflection which is not like propagation. Is the event point ever at the start of the table after some propagation, no. Try another with mirrors and as the reflection hits the first mirror, ask is the start of the tabletop still at the event, using a marker event to check, its another no. The photon is moving in a straight line at c, it is an absolute, it has energy, It started at the same point as all the others. It was never where the table observer thinks it started from.

The moment a photon leaves a frame, it is absolutely independent of that frame but the tabletop observer would like to think otherwise.

There is another interesting exercise to try here and that is to retain the tabletop left hand side with the center of the sphere and measure the time dilation for the tabletop frame which is now part of the absolute frame. What is the result there.

My observation here is that pre Lorentz, no satisfactory mechanical relativity was found. They all failed but if there had been one presented at the same time as Lorentz, which one would have been accepted.

I would like to know why mechanical relativity failed. What were the observations they failed on so I can try the same parameters against this one and understand why it fails too. I am sure people like Maxwell would not have accepted being disproved by mirrors or the word of a moving observer.

[CraigD]

Thanks for the sketch, Ver – I believe I now understand your thought experiment.

 

It (which I’ll call the light circle clock, or LCC) appear to be a variation on the “light clock” example (the light mirror clock, LMC) given in most textbook introductions to SR, and this wikipedia section, which I’ve referenced throughout this thread.

 

Rather than “ticking” at fixed time intervals as the LMC does, the LCC measures the passage of time by the increase in radius of a circle formed by the intersection of an expanding sphere of photons with a plane, the “table”.

 

The LCC doesn’t intuitively look like the LMC, because:

1. Our sketches of the LCC leaves out how one detects the photon from the “circle of light on the table”, while the LMC’s explicitly has the photon reflected back to an emitter/detector by a mirror. This isn’t a major issue – you could add reflectors at the circle and a detector at its center, and the LCC would be a physically possible experiment like the LMC.
   
2. The LMC assumes the distance between the e/d and the mirror is constant and the time for the photon to traverse it varies. The LCC assumes the traverse time is constant and the e/d to mirror distance – the circle’s radius – varies. Again, this isn’t a major issue.
   

However, the LCC appears to me to simply be a more complicated variation of the LMC.

 

Ask the observer with the table to point where the photon started from. He will point to the start point of the experiment at the left hand side of the tabletop. Now ask the observer, located at the sphere or absolute frame and ask if he was correct, "No he missed". Lets try again, This time the tabletop observer is asked to create a marker event at any time to indicate where he believes the photon started from. Every time he tries he misses. Try an exercise with mirrors, for sure the reflection returns to the moving frame, but, that is just it, a reflection which is not like propagation. Is the event point ever at the start of the table after some propagation, no. Try another with mirrors and as the reflection hits the first mirror, ask is the start of the tabletop still at the event, using a marker event to check, its another no.

Here, Ver, I think you go wrong.

 

Neither observer’s frame is privileged (“absolute”), other than that the photon’s emitter had zero velocity relative to one and nonzero velocity relative to the other.

 

If the table observer knows how the photon was generated – that is, knows what its frequency should be – he will be able to determine that what emitted it – the transition of an electron in a specific atom from one orbital to another, for example – had a velocity of 0.6 c perpendicular to the table relative to his inertial frame, and thus be able to calculate this location at the time it emitted the photon (assume it hasn’t been accelerated). It the table observer does not know how the photon was generated, she will be unable to conclude that the emitter did not have zero velocity relative to her frame at the time it emitted the photon.

 

... It [the photon] was never where the table observer thinks it started from.

Although each observer must know the photon’s emission frequency to know the relative velocity of its emitter, even if this isn’t known, assuming both are able to accurately detect the photon at 2 coordinates (in their own coordinates systems) and times, and they know their velocitiy relative to one another, by simply transforming its coordinated to a common system – which could be either, or neither, of theirs – both observers will agree on the photon’s path.

 

Neither observer ever need “think” the photon is in an incorrect location.

 

The photon is moving in a straight line at c, it is an absolute, it has energy, It started at the same point as all the others.

The photon is moving is a straight line at c as measured by either observer. However, its energy (which is directly proportional to its frequency) is not an “absolute”. For the table’s observer, its energy is 0.8 that observed by the sphere’s observer, due to redshift.

 

In short, Ver, I don’t see that you’re describing anything different from the usual geometric, “mechanical” description of SR that’s existed since it was published in 1913. You seem to be suggesting a problem with these descriptions, but I believe you perceive this problem due to the wrong conclusion that the table’s observer isn’t able to correctly calculate the path of the photon.

 

I would like to know why mechanical relativity failed. What were the observations they failed on so I can try the same parameters against this one and understand why it fails too. I am sure people like Maxwell would not have accepted being disproved by mirrors or the word of a moving observer.

I’ve not much encountered the phrase “mechanical relativity”, I think because it’s a given that special relativity is a classical mechanical theory, so the phrase strikes most people as redundant. Perhaps, Ver, you’re using it to mean a theory of the propagation of light that assumes it travels through a medium usually called the “luminiferous aether”.

 

Is this what you mean :QuestionM

 

If so, then it failed because it was shown experimentally that the measured speed of light – the distance traveled by a photon divided by the time it takes to travel it – is the same regardless of the velocity of the apparatus used to measure this distance and/or time. Aether theory predicts that, like the measured speed of sound in a medium depends on the speed of the measuring apparatus through that medium, the measured speed of light depends on the velocity of the apparatus through to the aether. 1887’s Michelson–Morley experiment showed this prediction to be false.

 

James Clerk Maxwell wrote that he believed light propagated through the luminiferous aether. Had he lived to read of it (Maxwell died in 1879, at the tragically young age of 48), I imagine the MM experiment would have shocked Maxwell as much as it did most physicists in 1887. I imagine, that like the experiment’s co-author Morley, he would have been skeptical of its result, and put a lot of time and effort into confirming the experiment’s accuracy and looking for a theoretical explanation that preserved the aether, before reluctantly concluding that it doesn’t exists, and a theory like special relativity is necessary to explain the MM experiment’s results.

[Ver]

Hi Craig

Sorry for being so slow. I think the particular point I cannot understand is the preferred frame, so perhaps we could just take a look at that for the moment.

 

With regards to the only absolute frame being c

I ask myself, what is that point between two photons heading in opposite directions. There must be an absolute there.

 

They move at c regardless of red or blue shift so still an absolute.

 

If I form a sphere of photons from a pinhead size event I can see its perfect symetry with every single photon in that sphere having moved the same distance, -- another absolute.

 

If we create a sphere and create another concentricly located to the first, They remain symetricaly co located. another absolute.

 

If we take as many frames as reasonable from all directions and all speeds passing through and creating events at the center of the co located spheres. all the new spheres will remain co located on the first, with no photon able to overtake another. still an absolute

 

Create another set of events precisely the same as in the previous paragraph and place objects of some mass right at the center of each set and retain them co located at the center of each set of spheres. Letting them both go, they will remain inertialy co locaed on each set of spheres. We created the center of each set of spheres 300,000km from each other. the objects of some mass will never move to or away from each other ---an important absolute. Time for these two objects has no option but to progress at an absolute.

 

Looking down at the spheres in one example the individual event creating frames can be located, their directions and their speeds, all relative to their own sphere and also their relative individual speeds, directions and locations relative to all the other frames. most importantly the time dilation of every frame. There are no abberations from this prefered frame

 

Just a note re Lorentz arriving on the scene and in Einsteins words "He brought theory into harmony " Lorentz did this by "subtracting from the Aether its mechanical and from matter, its electromagnetic qualities" I see this as a convenience to bend some of the rules.

 

Photons on an event centered sphere are reflected to return to their origin point and are "deflected" in any moving frame. Do the photons reflected in any moving frame go back to the "objects of some mass" located at the center of both spheres, well no. Does a tabletop crossing photon reflected to "return" to the frames "point of origin"-- go back to the object of some mass, no because the photon is not turned back 180 degrees. It was deflected to arrive at the frames future position.

 

The prefered or absolute frame will show the tabletop crossing photon is intersecting at less than c, measured by that frames slow clock at c.

Where does the absolute frame break down. It is hard to accept "there is no prefered frame"

[sigurdV]

Hi All!

 

Meanwhile remembering the CraigD question:

 

Who are we?

 

(We are, for example , creators of posts in Hypography.)

 

The above discussion of: Frames Events and Ourselves, has "weight".

 

This means its "speed" is somewhat restricted...

 

It will take "Hypography Time" to receive/understand its Message.

 

Then We are Moments. (modeled perhaps by strings)

 

Summing up: Let thoughts be expressed an understood :)