Frame of Reference as Subject in Subjective Idealism

[Cap'n Refsmmat]

Yes, it's crystal clear. The observer sees the light after about 8 units of time have passed and he has traveled a little over 8 units of distance.

I agree that: "It doesn't matter how it's measured: light will move at c,..."

But your point about length contraction would be more clear to me if you abandoned the graph and laid it out, as I suggested, "in the real world", say between sun and earth for reference points.

The Sun and the Earth aren't moving towards each other in the requisite way. Regardless, let me finish my point. It is a very simple one.

 

Let's look at this from the observer's perspective now. From the observer's perspective, the light is still moving at the same velocity, but the flashlight is approaching him. It looks like this:

 

 

Does that diagram make sense? We have a light pulse covering the same distance in the same time -- since it's light -- and the flashlight moving toward the observer.

[Iggy]

Yes, in this phase, before the "rewind." They both began firing lasers and took off toward each other at the same time. Their lasers would have gone the whole 8 light minute AU distance (past each other) while the travelers, at half lightspeed went half the distance. I just started simple before backing up to the shorter segments (fractions of the AU) to see when they would have seen each others' lights.

If the ships aren't moving towards each other then both lasers would travel the 1au distance between them. If the ships are approaching one another, starting at 1au when the lasers are fired, you should reconsider.

[owl]

The Sun and the Earth aren't moving towards each other in the requisite way. Regardless, let me finish my point.

 

Let's look at this from the observer's perspective now. From the observer's perspective, the light is still moving at the same velocity, but the flashlight is approaching him. It looks like this:

 

 

Does that diagram make sense? We have a light pulse covering the same distance in the same time -- since it's light -- and the flashlight moving toward the observer.

Yes. The observer sees the light go about 10 units of distance in about 10 units of time while he sees the flashlight travel only about 2 units of distance in that time.

 

Sorry but this has not yet made the case for length contraction in my mind. Maybe you are still working up to it, but I'm gone 'til Monday.

 

If the ships aren't moving towards each other then both lasers would travel the 1au distance between them. If the ships are approaching one another, starting at 1au when the lasers are fired, you should reconsider.

I give up yet again on communicating with you. The ships are moving toward each other from opposites ends of a one AU long "jousting arena." I said it clearly already! They fired lasers (at lightspeed, obviously) toward each other as soon as they took off at half lightspeed. They see each other's beam just before 6 minutes of travel, during which each ship traveled 3/8ths of the distance while their lights traveled 3/4ths of the distance.

The point, yet again: No distances "contracted."

Edited September 3, 2011 by owl

[Cap'n Refsmmat]

Yes. The observer sees the light go about 10 units of distance in about 10 units of time while he sees the flashlight travel only about 2 units of distance in that time.

 

Sorry but this has not yet made the case for length contraction in my mind. Maybe you are still working up to it, but I'm gone 'til Monday.

Don't worry, that gives me time to make my diagrams.

 

Now I ask the question: after four units of time, how far is the light from the flashlight?

 

From the flashlight's perspective, we have something like this:

 

 

From the observer's perspective, we have something like this:

 

 

That's slightly odd.

 

You can, of course, imagine a scenario where the flashlight is moving very close to the speed of light relative to the observer:

 

 

 

Very strange.

 

I hope this shows you that the constant speed of light makes the universe less intuitive than one might expect.

[Iggy]

their lights would each have gone the whole AU distance.

their lights traveled 3/4ths of the distance.

3/4ths is closer. 2/3rds is spot on.

 

The point, yet again: No distances "contracted."

Length contraction arises when comparing frames. You shouldn't expect to have to deal with it when only considering one.

Edited September 3, 2011 by Iggy

[swansont]

The cosmos is not real without our measurements? That is a form of idealism, with "frame of reference" substituted for "subjective" in "subjective idealism."

This philosophy goes all the way back to the absurd (cliche') claim of idealism that a tree falling in the forest doesn't make a sound if it is not heard. Iow, the world has no reality of its own but rather reality is totally dependent on perception and measurement.

 

I didn't say that.

 

I have repeatedly argued that we can trust measurements at rest with what is measured "hands down" over all those theoretical, extreme, near-light-speed frames of reference upon which the unverified theory of macro length contraction depends.

 

Why can't we trust measurements when we are moving?

[tar]

Iggy,

 

I am not sure why the frequency of the light observed, would not resolve any "differences".

 

It is well known that objects (stars) moving toward each other appear blueshifted.

 

For instance, if Alpha Centuri is 4.5 light years distant and now at the Sun is ts0 and now at Alpha Centuri is ta0, then the light we see coming from Alpha Centuri is a ta-4.5 year old image.

 

If we were to head off toward Alpha Centuri at C (say we are riding a photon) it would take us 4.5 years to make the trip. When we got there, the time would be ta4.5 years. During the trip we would have experienced 9 years worth of Alpha Centuri images. As we journeyed, life on Alpha Centuri would appear to be moving at double time, at twice the frequency. When we got there, it would be ts4.5 and ta4.5. But as we look back at the Sun in our rear view mirror, time is standing still, the photons from the Sun completely red shifted to something with a wavelength 4.5 lightyears long. As we park on Alpha Centuri and continue watching the Sun, we see it proceed normally at normal wavelengths, starting at ts0. We make the return trip and we see the Sun in double time, at twice the normal frequencies, and get home 9 years from when we left (ts9) and look back at Alpha Centuri and although it is at ta9, we look back and see it as it was at ta4.5.

 

 

Regards, TAR2

[Iggy]

If we were to head off toward Alpha Centuri at C (say we are riding a photon) it would take us 4.5 years to make the trip... But as we look back at the Sun in our rear view mirror, time is standing still, the photons from the Sun completely red shifted to something with a wavelength 4.5 lightyears long.

At what speed is the light from earth approaching us? Is it standing still next to us?

 

If the speed of light is constant, and it is, we need to be able to figure that the distance between our ship and a ray of light from earth changes by 300 thousand meters per second regardless of its frequency. From the ship, we need to be able to look at the light coming from earth and say "every second that light gets 300 thousand meters closer to us". If our ship is 300 thousand meters long it needs to take light from earth one second to traverse the length of the ship. Both the person on the ship and people on earth need to agree that it takes light one second to traverse the length of the ship.

 

This is not something that can be accomplished with classical mechanics.

[tar]

Iggy,

 

If our ship is 300,000 meters long, there is a second's difference in the now of the forward portion and the now of the aft. You have to pick your t0 to be either the fore or the aft and figure the now of the other from there.

 

What I take objection to is the thought that you can take both postions as happening similtaneously, in an objectively real way.

 

This, I think, is what this thread is about. There is an objective reality that we can only parse by considering it, from one place (here) and one time (now). We have the ability to put ourselves, our here and now, in the shoes of another here and now, and calculate the differences in time and space by shifting our frame of reference from the one to the other, and seeing that everything adds back perfectly. If I am 240 miles from you, you are 240 miles from me. If I am writing this 3hrs. before you read it, you are reading it 3hrs. after I write it.

 

What should we consider now? When I write this, or when you read this? Fact is, we both know how to switch back and forth, and know exactly what the other was refering to, or will be refering to.

 

This requires both a subjective experience of here and now, and a metaphysical understanding of a collection of here and nows, that all are connected in a regular, specific way that fit together flawlessy. You cannot "see" all this objective reality from any one place and time, but the place and time you are at. And you cannot "know" all this objective reality from any places and times but the ones you have either experienced or put yourself in the shoes of.

 

There is a suggestion that people make, that there is an objective reality, that is "greater" than the subjective reality that we experience and metaphysically understand. I do not believe that this makes any sense, and do not think that this is the way it has to be. We are of and in this objective reality. We sense it, and we know it. We experience it one time and place at a time. We have no other way to experience it. And by piecing together the various times and places, we can hold a working model, metaphysically, in our collective minds and libraries that lead us to believe correctly, that it is enormous in both size and duration, beyond our comprehension.

 

The "way" it works is certainly also complex and intricate, beyond our comprehension, but it can only be experienced from our perspective, and can only be understood from our perspective. If there are things in reality that have had no effect on our reality, are having no effect on our reality, and will never have any effect on our reality, then they are of no importance or consequence.

 

There is a "feeling" that people get, that they can contain it all, by understanding exactly how it works. I have a feeling that we already understand what contains who, and who contains what. Religious people have called it God. Physicists have called it Math. Some call it Nature, or the Universe, or Reality or simply "the way it is."

 

No amount of figuring will put us in a position where we are greater than it. We will always be in and of it. Just a matter of sharing the experience, and making it possible for others to do the same.

 

Iggy, I am very interested in understanding "how" everything works and fits together. And perhaps I will agree that classical mechanics cannot cover it. But I cannot discard a notion till I have the insight that naturally discards it.

 

There is not a point of view that can check what is happening at both the front and the back of the ship at the same time, except a point at the middle of the ship. And this point can only know 1/2 a second later. It can not know what is happening "now" at both ends, except in retrospect.

 

Regards, TAR2

[owl]

 

Very strange.

 

I hope this shows you that the constant speed of light makes the universe less intuitive than one might expect.

Yes, it is strange that light can not be pushed faster by a speeding flashlight, or laser, as in my scenario above. But it still makes since to me because light is not substantial like a bullet which does go faster from a gun speeding in the direction of the shot than from a resting gun.

But my beef with SR is the claim of length contraction, and I don't think you made a case for that above.

That is why I asked you to take your flashlight and observer out of graph mode and put them in the real where we do actually know distances between objects like earth and sun.

 

So I did it anyway with two ships one AU apart. Please review that scenario and reply to the point that there was no length contraction when seen as a whole, not limited to the frames of reference involved.

The light of each ship would have traveled the whole distance between the starting points in 8 minutes, so I backed it up to find out when they would see each other's light if they were traveling toward each other at half lightspeed.

In 6 minutes they each would have traveled 3/8ths the distance while their lights each travel 3/4 the distance, having just past the opposing ship, each now 1/8th AU beyond their own 1/4th AU position.. So the point of seeing each other's lights is 5+ minutes out and between their respective 1/4 Au and 3/8ths Au marks.

 

Again, no lengths contracted.

 

Swansont:

Why can't we trust measurements when we are moving?

We can as long as we "transform" them to accurate descriptions of the real world. If some aliens are on a near lightspeed mission to measure and describe or solar system and report back and they measure very oblate spheroids for all bodies in our system, their bosses back home would think ours a very strange system or they forgot to do the transformative math.

[Cap'n Refsmmat]

Yes, it is strange that light can not be pushed faster by a speeding flashlight, or laser, as in my scenario above. But it still makes since to me because light is not substantial like a bullet which does go faster from a gun speeding in the direction of the shot than from a resting gun.

But my beef with SR is the claim of length contraction, and I don't think you made a case for that above.

Why not? Are the distances after four units of time not different?

 

I chose my example very carefully to illustrate how the constant speed of light changes expectations. You cannot dismiss it by providing a separate example where you do not believe length contraction occurs.

 

"Here is an example where phenomenon x occurs." "Well, here's an example where I don't think it does!" "...so?"

[owl]

And, to back up a bit...

Me:

If the cosmos is real, with or without our measurements... then actual objects and distances are not dependent on how they are measured, Right?

Swansont

No, wrong. That's your philosophy and I don't agree.

 

If we can't trust measurements, then you don't really know the earth is a sphere. It could really (inherently) be a polyhedron or some odd shape. Or maybe it really is very oblate and the sphere is an illusion. How can you tell?

 

I have repeatedly argued that the closer we are to at rest with objects measured the more trustworthy the measurements. I have also repeatedly emphasized the importance of record keeping for science. There is massive and undeniable evidence from centuries of measuring earth from the at rest frame to verify its very well known measurements and description and no measurements done from that near light speed frame relative to earth which might give it a (clearly wrong!) 1000 mile diameter.

 

Your argument above is in serious denial of the facts.

And you clearly subscribe to idealism in your denial of realism as per my statement:

"actual objects and distances are not dependent on how they are measured..."

 

Why not? Are the distances after four units of time not different?

 

I chose my example very carefully to illustrate how the constant speed of light changes expectations. You cannot dismiss it by providing a separate example where you do not believe length contraction occurs.

 

"Here is an example where phenomenon x occurs." "Well, here's an example where I don't think it does!" "...so?"

The distance traveled by the flashlight is clearly less than the distance traveled by the light beam. We all know that a flashlight can not go as fast as the light it emits, nor can it make the light go faster via cumulative speed.

 

I find the graphs more confusing than examples laid out in "real space", i.e., using a well known and established distance for the illustration, as I did, but still employing the same "players", i.e., light, moving light emitting source(s), and observer(s).

[Cap'n Refsmmat]

The distance traveled by the flashlight is clearly less than the distance traveled by the light beam. We all know that a flashlight can not go as fast as the light it emits, nor can it make the light go faster via cumulative speed.

I was measuring the distance between the flashlight and the light beam, not the distance traveled by the flashlight. Please review the diagrams and let me know if you have any questions.

 

I find the graphs more confusing than examples laid out in "real space", i.e., using a well known and established distance for the illustration, as I did, but still employing the same "players", i.e., light, moving light emitting source(s), and observer(s).

Each unit on the position axis is one light-second; each unit on the time axis is one second. Better?

[owl]

I was measuring the distance between the flashlight and the light beam, not the distance traveled by the flashlight. Please review the diagrams and let me know if you have any questions.

 

Each unit on the position axis is one light-second; each unit on the time axis is one second. Better?

I did a thorough review, below, and yes I have questions.

From abstract to specific is always "better" for realism, but it was not essential to your graphs.

 

Graph, post 276 shows observer stationary, and from his perspective light pulse travels 10 units of distance in 10 units of time; flashlight travels 2 units of distance in 10 units of time.

 

Post 279, first graph, from flashlight’s perspective: In 8 units of time, observer appears to have moved 2 units of distance closer to flashlight while light pulse traveled 8 units of distance, intersecting (and being seen by) observer.

 

Second graph, from observer’s perspective: Light pulse has traveled 10 units of distance in 10 units of time, while flashlight has traveled 2 units of distance in 10 units of time. (Same as graph in post 276.)

You note that that is “slightly odd” and show that in the same time span, flashlight has traveled .5 distance units (looks like lots more on the graph) while light pulse has traveled 4 units, a difference of 3.5 units.

 

In graph three I see the observer moving 4 distance units toward the flashlight in 10 time units while the light pulse moved 6 units of distance in 6 units of time, intersecting the observer.

 

In the last graph:

The light pulse moves 10 distance units in 10 time units, intersecting the observer, while the flashlight moves 6 distance units toward the observer in 10 units of time. This means that the flashlight traveled .6 times lightspeed. Then you have another bracketed distance of 1.5 units from 2.5 to 4 on the distance scale, indicating the difference between flashlight’s and light pulse’s distance traveled in the same time span.

You note:

You can, of course, imagine a scenario where the flashlight is moving very close to the speed of light relative to the observer.

Tell me please, if i understood all that correctly, and then, please, if you will, tell me how those differences indicate length contraction, in the “real world,”...

This is a thread in part about the idealism, as I see it, of *theoretical* length contraction vs the realism that actual distances (or shapes or rod lengths, etc.,) do not change with measurements of them. That was the point of my scenario with a one AU 'track' of sorts laid out for two observes with lasers coming at each other.

 

Ps: Do you agree with Iggy's final statement in post 280?:

Length contraction arises when comparing frames. You shouldn't expect to have to deal with it when only considering one.

 

My "in the real world" scenario addresses the 'whole one AU 'track' and the over-all reality of who sees what and when and where along the track, not isolating "for the observers" (one take), and "for the light beams" (another take.) It is looking at the situation as a whole, i.e., the philosophy of reality not limited to individual frames of reference.

Edited September 7, 2011 by owl

[Cap'n Refsmmat]

Tell me please, if i understood all that correctly, and then, please, if you will, tell me how those differences indicate length contraction, in the “real world,”...

This is a thread in part about the idealism, as I see it, of *theoretical* length contraction vs the realism that actual distances (or shapes or rod lengths, etc.,) do not change with measurements of them. That was the point of my scenario with a one AU 'track' of sorts laid out for two observes with lasers coming at each other.

There is a distance between two objects: a flashlight and a photon. In one reference frame, that distance is longer than it is in another reference frame.

 

Is that point not sufficiently clear?

 

Ps: Do you agree with Iggy's final statement in post 280?:

Yes. Differences in length only become apparent when you compare lengths between two separate reference frames.

[owl]

There is a distance between two objects: a flashlight and a photon. In one reference frame, that distance is longer than it is in another reference frame.

 

Is that point not sufficiently clear?

 

 

Yes. Differences in length only become apparent when you compare lengths between two separate reference frames.

(a little out of phase here with my late editing...)

Yes, it is abundantly clear!

Is it clear to you that reality*, according to realism (*the actual distance between things and the photons they emit) does not depend on how it is measured from individual frames of reference?

 

You say, "there is a distance between two objects." Idealism says that distances between objects does depend on from where and at what velocity those distances are observed, i.e., all sizes, shapes, lengths/distances depend on how they are perceived... the world has no reality of its own independent of how we all important observers see it. Quite an observer centered take on the world/universe, as its reality and properties depend on how we observe them!

There is a distance between sun and earth, for instance. Observing that distance from extreme frames of reference does not make that distance change. If you think so you are an idealist and, again, I will rest my case.

 

This is a philosophical afterthought which turned into a kind of summary of this thread's topic. (Please excuse some repetition of the point of my last post.)

It's too bad that there are no philosophers of science here, or scientists with a grasp of this philosophical distinction (realism vs idealism.) The theory of length contraction and time dilation (reciprocals as I understand them) depends on an observer (frame of reference) dependent "reality" as if the world/cosmos had no intrinsic reality of its own, like shapes of cosmic bodies, distances between them, lengths of solid rods, etc.

Some say they "morph" with observation, and others say they don't, but that we can't know their descriptions/measurements for sure, because of the "cast in stone" dictum, "There are no preferred frames of reference."

Yet what scientist would not prefer being at rest with an object or length being examined and measured over flying by it at near lightspeed?

It is a false dictum, even if it is mainstream SR theory.

The results are clear and obvious if one is open to the evidence, which is well established with a long history of studying Earth. It is not in fact a severely oblate spheroid with a 1000 mile diameter, as per the high speed frame of reference we have beaten into the ground here. It is very nearly spherical, and we *know* its dimensions precisely from this long history of at-rest observation. There have been *no observations* of earth from the overworked high speed frame of reference. And if it were seen as above, that would only require the Lorentz math to "transform" it to its true shape.

I think its time to "get over" a squished nearly flat earth, an AU of 1/8th or so of the well known average distance of 93 million miles or so (8+ light minutes), and a meter rod of 12 cm or so, all based on this false dictum.

[Cap'n Refsmmat]

(a little out of phase here with my late editing...)

Yes, it is abundantly clear!

Is it clear to you that reality*, according to realism (*the actual distance between things and the photons they emit) does not depend on how it is measured from individual frames of reference?

Sure. So reality is in fact idealist?

 

You say, "there is a distance between two objects." Idealism says that distances between objects does depend on from where and at what velocity those distances are observed, i.e., all sizes, shapes, lengths/distances depend on how they are perceived... the world has no reality of its own independent of how we all important observers see it. Quite an observer centered take on the world/universe, as its reality and properties depend on how we observe them!

There is a distance between sun and earth, for instance. Observing that distance from extreme frames of reference does not make that distance change. If you think so you are an idealist and, again, I will rest my case.

You have agreed that the distance between the flashlight and the light changes in a different frame of reference, you evil idealist.

[tar]

Cap'n,

 

OK, can we go over a few definitions and assumptions?

 

"There is a distance between two objects."

 

Does this imply that this distance is invariant?

 

For instance, the traveling holder of the flashlight is "assuming" that the photon is 300,000 miles away from its launch position after one second, based on the constant speed of light, the invariance of seconds, and the invariance of miles. After one second, neither the holder of the flashlight or the photon is at the launch position of the photon. The holder is 150,000miles away, and the photon is 300,000miles. The observer sees neither the flashlight or the photon in his/her present time until some time after the events occurred, depending on his/her distance(real invariant distance) from the events in question.

 

Or put another way. If the holder of the flashlight where to launch a photon forward (in the same direction as his/her .5C travel, and launch one backward at the same moment, after one second would not the forward launched photon be 150,000 miles from the flashlight, and the rearward launched one 450,000 miles from the flashlight, according to both the expectations of the .5C holder and the observer?

 

Regards, TAR2

 

P.S.

 

Again, I think we only have two ways to take "is". One being our actual here and now, and one being the metaphysical "universal now" we figure to be the case.

[Cap'n Refsmmat]

"There is a distance between two objects."

 

Does this imply that this distance is invariant?

No; it varies between reference frames, as I demonstrated.

 

For instance, the traveling holder of the flashlight is "assuming" that the photon is 300,000 miles away from its launch position after one second, based on the constant speed of light, the invariance of seconds, and the invariance of miles. After one second, neither the holder of the flashlight or the photon is at the launch position of the photon. The holder is 150,000miles away, and the photon is 300,000miles. The observer sees neither the flashlight or the photon in his/her present time until some time after the events occurred, depending on his/her distance(real invariant distance) from the events in question.

Yes. We can assume, for the sake of argument, that the holder and the observer have photon detectors at strategic locations which have synchronized clocks, so they can tell exactly where the photon is at what time.

 

Or put another way. If the holder of the flashlight where to launch a photon forward (in the same direction as his/her .5C travel, and launch one backward at the same moment, after one second would not the forward launched photon be 150,000 miles from the flashlight, and the rearward launched one 450,000 miles from the flashlight, according to both the expectations of the .5C holder and the observer?

According to the observer, yes, this would be true. (Although it's 186,000 miles per second, rather than 300,000.) However, according to the holder of the flashlight, after one second the forward-launched photon would be 186,000 miles away and the rearward one 186,000 miles away. If he did not measure equal distances, then the velocity of a photon would not be constant.

[owl]

Sure. So reality is in fact idealist?

 

Huh? did you even read my last long winded post with its philosophical afterthought in summary of realism vs idealism?

There is no reality independent of how we see it? So this makes us observers the creators of reality and it morphs drastically with how we view it?

Good grief!

You have agreed that the distance between the flashlight and the light changes in a different frame of reference, you evil idealist.

You really know how to hurt a guy's feelings, calling me an idealist after all the explanation repeated throughout this thread about the difference between idealism and realism!

My evil plan is to debunk the nonsense of length contraction and time dilation by all those arguments above. My favorite three examples, yet again show that all the evidence points to a precisely measured and shaped nearly spherical Earth (no evidence for one with a 1000 mile diameter), that distance between Sun and Earth (being intrinsically real bodies with actual, real cosmos distance between them) does not vary with the FOR from which it is measured, and that the meter rod does not actually shrink to 12 cm just because it might be seen as such from an extreme velocity FOR.

 

I agreed that different FORs see distances differently and that lightspeed is constant. It can not be pushed faster by a speeding laser or flashlight, for instance. I explained how that makes sense to me.

We seem to be talking "past each other" about realism and idealism. I can live with "evil" and deluded idealists; but I think they make "bad" scientists who believe that their sacrosanct "no preferred FOR" makes the cosmos dependent on their perception of it.

 

...That there is no intrinsically real cosmos with objective properties in and of itself (and all its parts) until granted by its Creators, the Observers, each in their own little FOR.

('The poly/pan-theism of relativity.' A good title for a realist's paper/blog.)

[owl]

Late entry, just feeling like summing up this evening.

 

Realism says that the world is as it is, intrinsically, without our help.

 

Idealism says that the world is as we see it.

 

Take your pick.

 

Science at its best investigates what the world is, as it is and how it functions on its own, as if it were not being measured.

They call it objectivity in high school science classes.

 

Relativity now seems to claim that there is no "real world," because all different frames of reference define reality differently from each and every perspective.

This again introduces the basic question of how best to investigate the world.

If interested in this question please visit (or revisit) my arguments in this thread for an at-rest frame with the object of investigation.

[tar]

According to the observer, yes, this would be true. (Although it's 186,000 miles per second, rather than 300,000.) However, according to the holder of the flashlight, after one second the forward-launched photon would be 186,000 miles away and the rearward one 186,000 miles away. If he did not measure equal distances, then the velocity of a photon would not be constant.

 

 

Cap'n,

 

Well here is probably where I cannot understand what is meant. Why would he feel he needed to measure equal distances between his flashlight and a receding photon, and his flashlight and a photon he is chasing? He KNOWS he and his flash light are traveling at 93,000 miles per second because he is passing the stategically placed syncronized photon detectors, at that clip. These detectors have been placed on space bouys that are star powered and keep their position based on holding the angular position of a set of 12 "close" stars, 12 distant stars, and 12 "fixed" galaxies, precisely constant to the configuration existing when they where placed. The clocks on them where synchronized on Earth, flown each to their numbered buoy and back at a known speed and distance, any differences found were logged, so that when doing the final tally descrepencies could be subtracted or added as required. A recording device on each buoy would be hooked to its clock and detector which would timestamp every photon detection. We positioned 187 of these buoys each 1000 miles apart and tested, recorded and brought the records back to compare on Earth the results of a bevy of methods and facilities used to position and reposition the buoys (precisely tensioned thousand mile strand of fiberoptic cable, light flashes, radar, survey triangulation and all sorts of tests and measurement) until we were sure that the buoys WHERE indeed spaced in a straight line, 1000 miles apart.

 

Then we run our test and our .5C flashlight flashes forward and backward as it passes the 94th bouy. My contention is, that the 1st bouy will timestamp the passing of the flashlight 12:00:00, the 94th 12:00:01 and the 187th 12:00:02 and the 1st will timestamp the flash 12:00:01.5, the 94th 12:00:01 and the 187th 12:00:01.5.

 

Where am I going wrong?

 

Owl,

 

Why can the universe not be both subjectively real and objectively ideal?

 

Regards, TAR2

[Schrödinger's hat]

He KNOWS he and his flash light are traveling at 93,000 miles per second because he is passing the stategically placed syncronized photon detectors, at that clip.

No, he KNOWS that the detectors are moving, so are all the stars. He's staying still.

Then we run our test and our .5C flashlight flashes forward and backward as it passes the 94th bouy. My contention is, that the 1st bouy will timestamp the passing of the flashlight 12:00:00, the 94th 12:00:01 and the 187th 12:00:02 and the 1st will timestamp the flash 12:00:01.5, the 94th 12:00:01 and the 187th 12:00:01.5.

 

Good thought experiment, but you can't rely on a moving clock to measure time if you assume the speed of light is constant.

 

Now consider what happens from the light's perspective. According to the light it is still, and the buoys are moving. All of our mathematics and physics must work in this case just as well as the other case or they do not obey the postulate of relativity (laws of physics are the same in all inertial reference frames).

At some point bouy 1 passes it and displays 12:00:00 (let's say they pass really close so your reading is accurate, or you have some other means of synchronisation).

Some time later buoy 94 passes, reading 12:00:01 and the flash goes off.

Now: You have a beam of light going at c in either direction, one of the buoys is moving towards you at 0.5c, the other away.

Let's start with the approaching one:

Let's say the distance to the buoy is 1 unit when the light flashes. We don't know how big a unit is yet (unless we make some assumption about length contraction, but we can use it nonetheless.

The light hits it when [math]ct=1u+0.5ct[/math] or [math]t=\frac{1}{2}[/math]u/c time units in the future.

We know that the clock reads 12:00:01.5

The light hits the other buoy some time later, when [math]ct=1u-0.5ct[/math] or [math]t=\frac{2}{3}[/math] u/c time units in the future.

 

We now know that the two clocks displayed the same timestamp at different times, so the thing they measure can't be the time of the headlight.

We can do further thought experiments (or if we're clever use the data from this one) to figure out what exactly they are measuring (a combination of space a and time) in this frame.

Edited September 9, 2011 by Schrödinger's hat

[swansont]

Late entry, just feeling like summing up this evening.

 

Realism says that the world is as it is, intrinsically, without our help.

 

Idealism says that the world is as we see it.

 

Take your pick.

 

Since the two are not mutually exclusive, there has to be an option C. "Take your pick" represents a false dichotomy.

[owl]

Me:

Realism says that the world is as it is, intrinsically, without our help.

 

Idealism says that the world is as we see it.

 

Take your pick.

 

Swansont:

 

Since the two are not mutually exclusive, there has to be an option C. "Take your

pick" represents a false dichotomy.

 

TAR2:

Why can the universe not be both subjectively real and objectively ideal?

 

By “the world” I mean the cosmos and all of its parts, or physical reality in general.

As a retired psychologist I well know that everyone experiences "the world" in their own unique way.... the subjective experience of the world.

 

Some deny that “the world” exists intrinsically, objectively, ‘all by itself’ independent of the subjective experience of it. They are called subjective idealists in the realm of philosophy.

 

Others insist that the above is not true... that “the world” does in fact exist with all of its intrinsic properties, distances between objects, etc., independent of how it is observed or subjectively experienced. They are called realists or naturalists. They insist that the world (and all physical relationships) is real ‘all by itself.’

 

So, along comes the part of relativity theory (SR) that says “the world” is as it is observed/measured from whatever frame of reference (FOR), and there is no “preferred FOR.”

So, it either changes with every FOR from which it is observed (no intrinsic properties), or it doesn't change with every possible FOR, but we can not know which FOR yields an accurate description or measurement (all FORs being equally valid.)

 

I have argued that the claim, "the world is as it is observed/measured from whatever frame of reference" is a form of subjective idealism substituting FOR for “subjective”, even though a FOR can be an abstract, theoretical perspective not requiring a personal observer.

 

And, of course there is a philosophical difference between the “either” and the “or” positions above. The ‘either’ would be strict idealism where the world has no objective reality of its own, and perception or subjective experience is all there is. The ‘or’ position would be a form material agnosticism in which epistemology (science in particular) can not know the world as it is.

 

The specific schools of thought get complicated*. I would recommend a search and study of objective idealism, subjective idealism, realism, and naturalism.

 

*The complications arise from various mixes of ontology ( philosophy of what exists) and epistemology (how we know what exists.)

I obviously subscribe to naturalism/realism and believe that the ‘the world’ exists as it is independent of perception/measurement. Empirical science then develops the epistemology of how we know ‘the world as it is.' I have been very specific about the “preferred frame of reference” (at rest with object) for investigating any given object-as-it-is or distances between objects.