Frame of Reference as Subject in Subjective Idealism

[owl]

If you are going to complain about purported name calling, then you should not be a practitioner yourself.

 

This is so childish. You slam me with the implication that I am an amateurish crackpot or a troll. (I am in fact an amateur scientist, with no apology.) I reply with how lame your argument is. I am willing to be respectful if you are, but I will not hold my breath hoping for such an agreement, given your track record with me from the git-go.

But you did. You claim (as I bolded above) that either the universe's properties are intrinsic, or they aren't. That excludes a third option, that only some properties are intrinsic. So given the choice of either realism or idealism, how would you classify the answer that some properties are intrinsic and some are not? Is that realism, or is it idealism?

 

You missed the point that realism supports the general (non specific) proposition that "the world" in general is real, as it is, regardless of how we observe or measurement.

If you say that some of "the world's" properties are intrinsic, again, "good for you." You are a realist regarding those properties.

If you say some properties of "the world" are not intrinsic, then you are an idealist regarding those properties, because they will depend, for their pseudo-reality on the FOR from which they are measured.

Clear enough?

 

Roughly the same idea. We must simply take into account the time of observations. I think we agree.

 

Righto. Let us suppose that my room is actually on a railroad car moving down the tracks, and you're watching. You watch to see the path of the light and the path of me, over time:

 

 

I'm on a railroad car moving to the left, as you can see. The walls move as well, because they're attached to the railroad car. The light emitted by my laser travels at the speed of light and hits the walls. One light pulse hits just after four units of time, the other just after six.

Wait! You are still in the middle of a ten meter room, now a moving railroad car, and regardless of its movement, it will still take each laser the same amount of time to reach opposite walls. Lightspeed will get no help from the velocity of the car.

 

Had you seen the speed of light change between reference frames -- just like my speed is 0 in my frame and nonzero in yours -- it would all match up, and the light pulses would hit at the same times. Unfortunately, the speed of light is constant for everyone.

What I see doesn't change what I said above, and I still don't see an argument here for length contraction as a result of constant 'C.'

 

In other words, as per thread topic, FOR does not create or change reality.

 

Oh, no, another demerit! Turns science into a popularity contest, to the discredit of this forum... a lot like name calling as an argument.

Edited September 14, 2011 by owl

[Cap'n Refsmmat]

Wait! You are still in the middle of a ten meter room, now a moving railroad car, and regardless of its movement, it will still take each laser the same amount of time to reach opposite walls. Lightspeed will get no help from the velocity of the car.

Hang on. The light is moving at exactly the same speed in both diagrams. It's not getting any help from the railroad car. Take a look. Here, the light takes five units of time to travel five meters:

 

 

Here, the light also travels five meters in five units of time:

 

 

It's just that the train moves while it does so. The speed of light hasn't changed at all! The slopes (distance traveled / time taken) of the light lines are exactly the same, indicating they travel the same distance in the same amount of time. I explicitly drew the light not getting any help from the railroad car.

 

If the diagrams appear incorrect to you, perhaps you could suggest corrections or adjustments.

 

What I see doesn't change what I said above, and I still don't see an argument here for length contraction as a result of constant 'C.'

Well of course. I'm not trying to prove length contraction yet.

[owl]

Cap' n R:

Well of course. I'm not trying to prove length contraction yet.

Your piece-meal approach is not working for me, as evident in my last reply. I can't even think of a good question to ask for clarification. So, I will patiently wait until your argument is complete, assuming that you will eventually make your case for length contraction, and then I can respond to the completed argument.

Thanks.

(Obviously I have seen both graphs already and know that the train is moving and lightspeed is constant.)

Edited September 14, 2011 by owl

[Cap'n Refsmmat]

I'm giving a concrete example of the relativity of simultaneity, not length contraction.

 

The aim is to show that two events (the light hitting the walls) occur simultaneously from one perspective (mine) but not simultaneously from another perspective (yours, standing next to the tracks). Is that not clear?

[Schrödinger's hat]

My point in defining time as event duration for physical events (with examples) and space (in its linear dimension) as the distance between real objects in space... is to demonstrate that time is not something that slows down (as per "time dilation"), even though physical processes (like clocks ticking) slow down in certain circumstances,... and that the real distance between objects (like sun and earth) does not vary to extremes with the FOR from which they are measured, as length contraction would have it.

This is relevant to the thread topic in that my above argument grants reality to physical objects, the distances between them, and the elapsed time for those processes to happen, independent of whether or not any of the above are measured or from what FOR.

Okay, was really trying not to go here, but what the hell do you mean?

Define duration.

Define distance.

No circular logic or tautologies.

In a limited sense, this supports the length contraction argument that there is no reality to distances between objects independent of measurement.

Very close. According to SR, distance is not an invariant.

It's not a frame independant qauntity, exactly the same category as angular size, or height.

Angular size is still objective. If I tell you to measure the angular size of the moon from New York on the 10th of December 2011 you will get an answer that anyone with skills in geometry can predict by taking their own measurements from another time or place.

Height also requires a frame before it is meaningful, I think this old joke illustrates the point best:

 

An engineer, a mathematician, and a physicist were standing around the university flagpole when an English professor wandered by. "What are you doing?" he asked. "We need to know the height of the flagpole," said one, "and we're discussing the formulas we might use to calculate it." "Watch!" said the English professor. He pulled the pole from its fitting, laid it on the grass, borrowed a tape measure and said, "Exactly 24 feet." Then he replaced the pole and walked away. "English professor!" sneer the mathematician, "We ask him for the height, and he gives us the length."

 

 

You totally ignore my thought experiment in support of realism, as follows:

 

 

The earth-sun distance has a "life (reality) of its own" and the distance varies with earths (elliptical) orbital position, not with how it is measured from different FORs.

This point directly addresses the thread topic.

I could not make any sense of your thought experiment nor think of any sensible reply. Possibly due to you operating on some definition of distance unknown to me.

Edited September 15, 2011 by Schrödinger's hat

[Iggy]

This is so childish. You slam me with the implication that I am an amateurish crackpot or a troll.

If you don't want to be taken as a crackpot and troll then try discussing in good faith. You asked the Captain to show that relative simultaneity is a logical consequence of a constant speed of light. He proved exactly that. Have a little decency and either agree, disagree, or admit that you don't understand.

 

A constant speed of light has many undeniable logical consequences. You avoid them with dismissive rhetoric and that is rude, trollish, and childish.

Edited September 15, 2011 by Iggy

[owl]

I'm giving a concrete example of the relativity of simultaneity, not length contraction.

 

The aim is to show that two events (the light hitting the walls) occur simultaneously from one perspective (mine) but not simultaneously from another perspective (yours, standing next to the tracks). Is that not clear?

Yes, I get that the bystander's FOR is different than the guy's in the moving train car, and both see things differently, if that was your point.

I just reviewed the last two pages of our conversation to see where we went from my challenge of length contraction to your argument for the relativity of simultaneity.

I found it and will very briefly review. We were discussing one of my favorite challenges to length contraction, the variability or not the Earth-Sun distance, the Au. I argued that it changes only with the irregularity of the elliptical orbit, and you were were, I think, arguing that it also changes with different frames of reference (FORs.)

The forum topic challenges the reality of changing shapes and distances between objects due to changing FORs.

 

I gave the realists view of simultaneity (and common definition) above as simply "happening at the same time." Clearly it takes time for light to travel and convey information, so the above does not imply "seeing" such a simultaneous happening at the same time from different FORs.

We recently had this exchange:

Me:

Thanks for the clarification. An event is an object or happening with a "timestamp." How is that different (if it is) than my example of sun-earth distance-between-objects right now (with timestamp on measurement) and a few months from now (new timestamp) showing a bit different distance-between-objects?

(Still working toward establishing that that distance does not (actually) vary to extremes with different FORs, but just with position in orbit.

You:

Roughly the same idea. We must simply take into account the time of observations. I think we agree.

 

Now to a review of your offer and my request for "a concrete example" (with an eye to "example of what?)

You:

The "actual distance" is s, and no, it does not change with different observational frames. Delta x and Delta t might, though.

Me:

We all know that the distance between earth and sun changes over time because of the elliptical orbit.* The question here is whether it also changes with observational frame, called "length contraction."

 

Then again you invoke the magic of the spacetime (or rabbit pelt) interval, s and say that "it", "actual distance" doesn't change with different observational frames but "delta x" and delta t "might" change.

But delta x is the spatial distance between two events (bodies, in the common vernacular), and it might change with a different FOR?

 

How exactly does this theory make sense in regard to the earth getting closer to the sun in the "length contraction" way. (Ref: * above.)

You:

Delta x is the spatial distance between two events which occur at the same time. (You wouldn't measure the distance between the Earth now and the Sun ten years from now.) Since simultaneity is relative (a logical consequence of the constant speed of light -- I can give a concrete example if you'd like), necessarily spatial distance is as well. But s is not relative.

(My bold.)

In the context of what I just said about simultaneity and (basically) signal delay, the above denies the dictionary meaning and makes "happening at the same time" dependent on delay in seeing the happening from different FORs at different times. If that is a misconception, then so is the assumption that spatial distance is also relative.

I now regret that I took up your offer. I had already shared my understanding of simultaneity, and agree only that there is a time lag between observers who see the same (simultaneous) event from different FORs, ergo at different times.

 

That still leaves me with the same old question for you about length contraction. I'll state it differently for variety:

Do the Au, the shape of Earth and the meter rod all stay invariant (as is, objective, independent of measurement) when you combine space and time into a "rabbit pelt" or whatever concept, or do you believe either that they do change with FOR or that there is no way of knowing their true measurements and shapes because of the "no preferred FOR" dictum of relativity?

Edited September 15, 2011 by owl

[Cap'n Refsmmat]

In the context of what I just said about simultaneity and (basically) signal delay, the above denies the dictionary meaning and makes "happening at the same time" dependent on delay in seeing the happening from different FORs at different times. If that is a misconception, then so is the assumption that spatial distance is also relative.

I now regret that I took up your offer. I had already shared my understanding of simultaneity, and agree only that there is a time lag between observers who see the same (simultaneous) event from different FORs, ergo at different times.

I don't think you understand; signal delay -- the delay in "seeing the happening" -- is not relevant to my example. It is not even included in my example diagrams. The diagrams show the light moving and intersecting with the walls; they do not show the time it would take for light to travel back from the walls to the observer.

 

The difference in times on the moving railcar is due to the motion and the constant speed of light, not due to the time it takes for me to realize the light has reached the walls.

 

Please review the diagrams and let me know if you have any questions.

 

That still leaves me with the same old question for you about length contraction. I'll state it differently for variety:

Do the Au, the shape of Earth and the meter rod all stay invariant (as is, objective, independent of measurement) when you combine space and time into a "rabbit pelt" or whatever concept, or do you believe either that they do change with FOR or that there is no way of knowing their true measurements and shapes because of the "no preferred FOR" dictum of relativity?

I will get to this once the basics are clear. At this point, addressing your question is premature, since you don't yet seem to grasp the fundamentals of relativity.

[owl]

I don't think you understand; signal delay -- the delay in "seeing the happening" -- is not relevant to my example. It is not even included in my example diagrams. The diagrams show the light moving and intersecting with the walls; they do not show the time it would take for light to travel back from the walls to the observer.

 

The difference in times on the moving railcar is due to the motion and the constant speed of light, not due to the time it takes for me to realize the light has reached the walls.

 

Please review the diagrams and let me know if you have any questions.

 

I will get to this once the basics are clear. At this point, addressing your question is premature, since you don't yet seem to grasp the fundamentals of relativity.

Repeat from my post 328:

Your piece-meal approach is not working for me, as evident in my last reply. I can't even think of a good question to ask for clarification.

Yes, I know lightspeed is constant, same time to reach either wall 5 meters away, regardless of the train's speed, also regardless of the two FORs from which light hitting the walls is seen.

You said:

The aim is to show that two events (the light hitting the walls) occur simultaneously from one perspective (mine) but not simultaneously from another perspective (yours, standing next to the tracks). Is that not clear?

 

So, the lights hit both walls at the same time (simultaneously), in the real world, period. You see it happen simultaneously because you are in the middle and not moving relative to the train. I see a lag between one light hitting the wall and the other, because I am not midway between them, and the whole shebang is moving relative to my position on the tracks.

Yet signal delay and the difference in observer velocity is not relevant? No, that is not clear.

You say that I "... don't yet seem to grasp the fundamentals of relativity." I disagree with the assertion of relativity that simultaneity is relative. Things that happen at the same time do so regardless of differences in when they are seen to happen due to differences in FOR.

The differences in our FORs does not effect the simultaneity of the lights hitting the walls, but just when each of us see it happen.

Your turn.

 

If you don't want to be taken as a crackpot and troll then try discussing in good faith. You asked the Captain to show that relative simultaneity is a logical consequence of a constant speed of light. He proved exactly that. Have a little decency and either agree, disagree, or admit that you don't understand.

 

A constant speed of light has many undeniable logical consequences. You avoid them with dismissive rhetoric and that is rude, trollish, and childish.

I am and always have been sincerely "discussing in good faith." Your false judgment and resulting accusation that I am not is personally insulting. Likewise your judgments and insults that I am indecent, rude, trollish and childish.

Cap 'n R has not "proven" that relative simultaneity is a logical consequence of a constant speed of light. I "disagree." I seriously doubt if you were able to follow my argument against. I'll make it as simple as I can for you:

Now IS now regardless how long it takes light to convey a "now happening event" from one location to another. I argue from realism in which what is happening now does not depend on the FOR from which it is seen.

I will not be replying to any more of your posts.

 

I have a little free time to reply to one of Schrodinger's hat's recent questions, bolded below.

Responding to my:

I mean to assert that "time dilation" and the "time" part of "spacetime" are only artifacts of measurement. Duration is elapsed time from "tick" to "tick" or from sunrise to the next sunrise at a given surface location on Earth... or from one "now" to another during any physical process.

 

Schrodinger's hat:

Well this is actually useful for moving the discussion forward.

How do you define the reference frame from which all measurements should be taken?

 

At rest with the object or distance being measured, as far as is possible. Otherwise as close as possible to an at rest frame with whatever is being measured.

Whizzing by at near lightspeed will not be a "preferred frame" of observation for any scientist with control of his experiment.

Wow! Someone is really mad at me. Another two demerits! (Is there a limit per post?) I wonder who...

 

But seriously folks,

To another "decent" question from Schrodinger's hat:

Replying to my:

The earth-sun distance has a "life (reality) of its own" and the distance varies with earths (elliptical) orbital position, not with how it is measured from different FORs.

You said:

I could not make any sense of your thought experiment nor think of any sensible reply. Possibly due to you operating on some definition of distance unknown to me.

The definition of distance from a realist is how far it is (in any conceivable units of distance) from one point, locus or object in the real cosmos to another, as illustrated in my quote above.

That does not change with how it is observed.

Edited September 16, 2011 by owl

[Cap'n Refsmmat]

Yes, I know lightspeed is constant, same time to reach either wall 5 meters away, regardless of the train's speed, also regardless of the two FORs from which light hitting the walls is seen.

 

So, the lights hit both walls at the same time (simultaneously), in the real world, period. You see it happen simultaneously because you are in the middle and not moving relative to the train. I see a lag between one light hitting the wall and the other, because I am not midway between them, and the whole shebang is moving relative to my position on the tracks.

Yet signal delay and the difference in observer velocity is not relevant? No, that is not clear.

Your position is also irrelevant in this diagram:

 

 

Notice the very specific lack of a "You Are Here" arrow. Where you stand along the tracks will not change the diagram or the outcome of the experiment -- it will merely shift everything uniformly left or right.

 

In very explicit words: If the wall is moving towards the light, the light will reach the wall sooner. If the wall is not moving towards the light, the light will reach the wall later. In different reference frames, the light never changes speed; the wall does.

 

Is that not clear?

 

You say that I "... don't yet seem to grasp the fundamentals of relativity." I disagree with the assertion of relativity that simultaneity is relative. Things that happen at the same time do so regardless of differences in when they are seen to happen due to differences in FOR.

The differences in our FORs does not effect the simultaneity of the lights hitting the walls, but just when each of us see it happen.

Your turn.

You don't seem to understand what the assertions of relativity even mean. Disagreeing with them is another matter entirely.

[tar]

Cap'n,

 

Is the speed of light constant, or is the measured speed of light constant? I am trying to understand the implications of your diagram.

 

The diagram seems to be saying to me that it will take longer for the light to hit the left wall than it takes to hit the right wall. It will not hit both walls simultaneously but indeed will hit the right wall first, and later will hit the left wall. The distance the light has to travel to reach the right wall is shorter than that which it has to travel to hit the left, since the right wall moved to the left, toward the point of firing, and the left wall moved to the left away from the point of firing. This proves to me only that if the me was to measure the time it took light to reach each wall, by timing its return from mirrors on each wall he/she would find that it took a longer time to return from the left wall, than from the right wall. Already knowing the distance between himself and each wall, and already knowing that light travels one unit per second, his/her only conclusion could be that his/her room is moving in the direction of the left wall.

 

Regards, TAR

 

Schrödinger's hat,

 

I'll take here and now as the preferred frame of reference.

I'll take distance from here, in any direction to be the separation from here to there in meters.

I'll take time from now, in either direction to be the separation from now to then in seconds.

 

The things that are happening now everywhere will not be real to me until their effects reach me, which will take at least some amount of time, equal to or greater than the time it takes light, traveling at 300,000 meters/sec. to reach here from there. Which or course will be another now, 'cause it will take some time, and will be another here, because I will have moved by then.

 

Regards, TAR2

Edited September 16, 2011 by tar

[Cap'n Refsmmat]

Is the speed of light constant, or is the measured speed of light constant? I am trying to understand the implications of your diagram.

The speed of light is measured to be the same no matter where you are, how fast you're going, or what reference frame you're in.

 

The diagram seems to be saying to me that it will take longer for the light to hit the left wall than it takes to hit the right wall. It will not hit both walls simultaneously but indeed will hit the right wall first, and later will hit the left wall. The distance the light has to travel to reach the right wall is shorter than that which it has to travel to hit the left, since the right wall moved to the left, toward the point of firing, and the left wall moved to the left away from the point of firing. This proves to me only that if the me was to measure the time it took light to reach each wall, by timing its return from mirrors on each wall he/she would find that it took a longer time to return from the left wall, than from the right wall. Already knowing the distance between himself and each wall, and already knowing that light travels one unit per second, his/her only conclusion could be that his/her room is moving in the direction of the left wall.

You were exactly right up until you concluded the person inside the railcar would observe that the room is moving. The person inside the railcar observes this version of events:

 

 

...since from his perspective, the railcar is not moving relative to him. It's only the person on the side of the tracks that would observe a difference in times, caused by exactly the mechanism you explained.

[tar]

P.S. to Cap'n,

 

Wait, the return trip from the mirrors would need a couple more diagrams. After the bounce of the right wall, the laser is "chasing" the me, and will have to travel a longer distance than it did to hit the wall in the first place, and the laser that hit the left wall, although it traveled more than five meters to reach the left moving wall will have to travel less than 5 meters to get back to the me. The me will NOT measure the bounce off the right wall as shorter than the bounce off the left wall. The me will measure them the same. Off the right wall he/she will measure 10 units (4 plus 6) and off the left wall he/she will measure 10 (6 plus 4.)

 

The me's only conclusion is his/her room is standing still! (although the me is incorrect.)

 

P.P.S. cross posted

 

Cap'n,

 

Although, if the mirrors had energy sensors, or sensed the wavelengths of the laser, the right mirror would say that the laser was blueshifted to a higher energy or frequency, since the wavelengths were shorter, and the left wall mirror/sensor would say that the laser was of a lower energy, since the wavelengths were longer. The me would get back the same energy he/she put out since the return trip of each of lasers would be the reciprocal of respective trips to the wall, the blue shifted laser the right wall sees, redshifted on the way back to the me, and vice a versa to the left wall.

 

Regards, TAR2

 

the me may still have some ways to discover the room is moving to the left

 

Perhaps Michelson-Morley found no motion through the ether 'cause the upwind and downwind paths canceled each other out. In addition to measuring the fringes that found the wavelengths back in sync on return, they should have measured the energy hitting the upwind and downwind mirrors.

Edited September 16, 2011 by tar

[Iggy]

You avoid them with dismissive rhetoric.

I will not be replying to any more of your posts.

You couldn't have illustrated my point more clearly.

 

Yes, I know lightspeed is constant, same time to reach either wall 5 meters away, regardless of the train's speed, also regardless of the two FORs from which light hitting the walls is seen.

 

So, the lights hit both walls at the same time (simultaneously), in the real world, period.

Exactly wrong. It isn't a matter that can be debated. Learn to read the diagram. Try this site: http://www.phy.syr.edu/courses/modules/LIGHTCONE/events.html

 

You see it happen simultaneously because you are in the middle and not moving relative to the train. I see a lag between one light hitting the wall and the other, because I am not midway between them...

The position of the observer is irrelevant. You just don't realize how your lack of understanding shows and how much you would benefit, and your ability to argue the topic would benefit, from learning the basics. It is like Dr. Rocket said way back, "the problem is that you don't know that you don't know"

[Cap'n Refsmmat]

Wait, the return trip from the mirrors would need a couple more diagrams. After the bounce of the right wall, the laser is "chasing" the me, and will have to travel a longer distance than it did to hit the wall in the first place, and the laser that hit the left wall, although it traveled more than five meters to reach the left moving wall will have to travel less than 5 meters to get back to the me. The me will NOT measure the bounce off the right wall as shorter than the bounce off the left wall. The me will measure them the same. Off the right wall he/she will measure 10 units (4 plus 6) and off the left wall he/she will measure 10 (6 plus 4.)

 

The me's only conclusion is his/her room is standing still! (although the me is incorrect.)

Hm. I swear I replied to this...

 

You're conflating reference frames. Keep in mind that there's multiple reference frames possible: we could observe this situation from a car driving past, for instance, or from an airplane. Each will see a different velocity of the railcar, and one can't say there's one definite railcar velocity. It depends: velocity relative to what?

 

Any detector or observer on the railcar will measure it to be standing still, because it is not moving with respect to him. A detector on the railcar won't measure a Doppler shift in the light. A detector used by an observer in a racecar driving past will notice a pronounced Doppler shift, and a detector used by the couple picnicking in the park next to the tracks will notice a lesser Doppler shift.

 

There's no way for the observer on the car to measure the car at anything but rest, since the car is indeed at rest with respect to him.

[tar]

Has this been tried?

 

Match 12 lasers as closely as you can to be outputting the same frequency and power.

 

Place them facing in 12 different directions from a center point, at each end of 6 different axis, (same configuration as twelve ping pong balls would fit around a center ping pong ball) Place a CCD a meter from the business end of each laser, and measure and record the output of each CCD as precisely as you can. Have the whole arrangement housed in an approximately 2 meter diameter sphere. Rotate the sphere to various positions (ie turn one of the axis end for end) and record any change in reading of any of the voltage outputs of any of the twelve CCD, of course recording the "up" position of the sphere in reference to the Earth, the latitude and longitude of the experiment, the time of day, date, year and so forth so you know the attitude of each laser in each of the recorded trials.

 

If a pattern emerged, where a certain "direction" got higher readings and the opposite direction got lower...it might tell us which way we are headed.

[Cap'n Refsmmat]

Has this been tried?

 

Match 12 lasers as closely as you can to be outputting the same frequency and power.

 

Place them facing in 12 different directions from a center point, at each end of 6 different axis, (same configuration as twelve ping pong balls would fit around a center ping pong ball) Place a CCD a meter from the business end of each laser, and measure and record the output of each CCD as precisely as you can. Have the whole arrangement housed in an approximately 2 meter diameter sphere. Rotate the sphere to various positions (ie turn one of the axis end for end) and record any change in reading of any of the voltage outputs of any of the twelve CCD, of course recording the "up" position of the sphere in reference to the Earth, the latitude and longitude of the experiment, the time of day, date, year and so forth so you know the attitude of each laser in each of the recorded trials.

 

If a pattern emerged, where a certain "direction" got higher readings and the opposite direction got lower...it might tell us which way we are headed.

Something to that effect has been tried:

 

http://math.ucr.edu/home/baez/physics/Relativity/SR/experiments.html#round-trip_tests

 

This is one of the most accurate limits on any anisotropy in the round-trip speed of light in a laboratory. They measured the beat-frequency between a single-mode laser on a rotating table and a single-mode laser fixed to the Earth to put a limit on such an anisotropy of 3 parts in 1015. Due to the construction of their rotating laser, this can also be interpreted as a limit on any anisotropy of space. This is a round-trip experiment because of their use of a Fabry-Perot etalon to determine the frequency of the rotating laser. Note that their limit on the round-trip anisotropy corresponds to a round-trip speed of less than 0.000001 m/s (!); in terms of the more usual one-way anisotropy it is 30 m/s.

 

The beat frequency gives the difference in frequency between lasers; as they changed the orientation of the rotating laser, any Doppler shifting would cause the beat frequency to change. It did not.

[tar]

duh, or more simply, put one laser in a tube a meter long, pointed at a ccd at the other end and look at a reading of the voltage level output. Then point the tube around, and see if the reading changes. If it does, the highest reading is the direction you are traveling through the ether.

 

or is it aether

 

Cap'n,

 

Well you did answer. Many times. I just don't get it.

 

A photon has to travel a unit of distance in a unit of time.

 

Doesn't it?

 

Regards, TAR2

Edited September 16, 2011 by tar

[Cap'n Refsmmat]

Cap'n,

 

Well you did answer. Many times. I just don't get it.

 

A photon has to travel a unit of distance in a unit of time.

 

Doesn't it?

Yes, it does. Take a look at both of the diagrams I gave again: the one for the observer on the train and the one for the observer on the side of the tracks. In each case, the light travels a unit of distance in a unit of time -- it does not change speed. What changes between reference frames is the relative velocity of the railcar.

[tar]

maybe I almost get it. I will sleep on it. Thanks Cap'n.

[md65536]

Wow! Someone is really mad at me. Another two demerits! (Is there a limit per post?) I wonder who...

One can only vote once on a particular post. So it is not someone; it is someones. I voted, to show that I wasn't one of the original 2 votes. Also I can only make one negative vote per day... I often find myself faced with a "you have reached your quota of negative votes" message.

 

I don't think that it indicates that people are "mad at you". I myself try to vote + on any message that is helpful, that makes me "get" something or is enlightening or educational. I try to vote down posts that are negatively helpful or damaging, including misleading arguments, misinformation, spiteful insults, etc.

 

I think the negative votes are mostly indicative that your students here in this thread are not getting your lesson.

I myself think that you're thisclose to disproving relativity, and dismantling and rewriting all of science as well as philosophy and a lot of history as well. Except of course for just a few questions that remain still unanswered. But I also believe that SR is correct.

 

 

See, when a student has already decided that the teacher is wrong, the student is not going to learn.

Even with the unusually low student-to-teacher ratio here in this thread, and the amount of attention devoted to teaching the lesson, and the endless repetition of the lesson, it remains endlessly unlearned. But I wonder, is it rewarding to teach with persistence to a problem student, because the lesson can still benefit others? Or is it foolish to try to teach a student who refuses to accept the lesson?

 

 

 

the ether.

or is it aether

it's "either"

 

 

 

 

Learn to read the diagram. Try this site: http://www.phy.syr.e...ONE/events.html

I agree that it's helpful to learn about the diagrams in order to understand them.

 

These concepts aren't going to make sense unless one lets go of some preconceptions from classical physics (including assumption of universality of simultaneity).

Also, it's difficult to learn relativity from scratch by looking at diagrams alone.

 

With a little understanding of the basics of relativity, the diagrams make a lot more sense. Understanding the diagrams makes some of the concepts of relativity easier to understand. Learning a bit from one helps with the other; they go hand in hand. Without one, the other alone can be quite counterintuitive.

 

 

 

[Schrödinger's hat]

At rest with the object or distance being measured, as far as is possible. Otherwise as close as possible to an at rest frame with whatever is being measured.

Whizzing by at near lightspeed will not be a "preferred frame" of observation for any scientist with control of his experiment.

I didn't mean anything to do with which frame we'd want to do our experiment in.

I meant, Which frame are our measurements (such as measurements of the laws of physics) correct in.

 

You said that light can't be pushed along by a moving object, so say I have a million objects in random places moving at a million random velocities in a million random directions.

 

Say I set up a million experimental apparatus which consist of two sets of two sensors, a light, and a clock.

 

On each object, each pair of sensors picks a random object, lines up with it, and will record (on each sensor) the time it sees the light on that object turn on.

 

So I will wind up with a distance and a time for each pair of sensors.

We divide each distance by the corresponding time.

 

Which object or objects get(s) the right value for the speed of light?

 

The definition of distance from a realist is how far it is (in any conceivable units of distance) from one point, locus or object in the real cosmos to another, as illustrated in my quote above.

That does not change with how it is observed.

Here we go. This is why I didn't want to do this.

Define "how far it is" from one point to another.

You've already used 'distance' so you can't say that.

And saying 'the thing measured by meter sticks' is out too because you told me that's tautilogical.

Hint: If you feel like saying something along the lines of 'how many meters/other units of distance it is' just skip it and define a meter.

 

I'll take here and now as the preferred frame of reference.

I'll take distance from here, in any direction to be the separation from here to there in meters.

I'll take time from now, in either direction to be the separation from now to then in seconds.

 

The things that are happening now everywhere will not be real to me until their effects reach me, which will take at least some amount of time, equal to or greater than the time it takes light, traveling at 300,000 meters/sec. to reach here from there. Which or course will be another now, 'cause it will take some time, and will be another here, because I will have moved by then.

 

You appear to be following roughly the same train of logic I was intending to lead you on with Capn, but I'll respond anyway.

 

So if we take here and now as a frame in which the laws of physics are correct (and the speed of light is a law of physics) then from my point of view, wherever I am, and however I'm moving, a beam of light aimed towards/away from me will get 3*10^8 metres closer/further to/from me every second, in addition to this the measurements I take are just as valid/correct as those from any other here and now.

 

I might be able to find out that isotropy/everything else I can see is moving at some rate in my frame (to pick a value at random they might be moving at 0.1c +/- 500km/s), but I am still stationary.

If this is wrong, then there is a preferred frame in which measurements are right (in which case we go back to my question, of which one is it?)

 

In which case in your buoy experiment either taking measurements from the FOR of the lamp is just as valid as measurements from the frame of the buoys, or:

One of the assumptions (postulate of relativity or constant c) is wrong.

 

 

In terms of the defining distance thing, that was mostly aimed at Owl, but you can play along at home if you like. The rules are basically:

1) Write down 'Distance is __________' then,

2) if ________ is just a synonym for the concept of distance, write down '__________ is _________'

3) If you're not sick of it yet go to step 1, else go to step 4

4) Point to a ruler and say 'this is a foot/metre/30 centimetres/yard etc' -- ie. distance is the thing we measure with metre sticks.

 

You can do the same with time, too.

 

The me's only conclusion is his/her room is standing still! (although the me is incorrect.)

You keep saying things like this which reinforces my belief that you don't quite understand the postulate of relativity.

 

This is basically the thinking physicists had in the late 19th/early 20th century, but the thought process that came from this goes something along the lines of:

If I had a lot of mes moving at different velocities, only one of them would be right

We can determine some quantity/law of physics before hand and all the mes can measure it

Then we know which me is right

So we know which way the ether is moving compared to us

 

In spite of experiment that was done, and all the data that could be found, no experiment could be conceived of that would tell you how fast you were moving, unless you looked at something else and said 'I'm moving at ____ relative to that'

 

Every theory that anyone could think of got crossed off of the list one by one until two remained:

Relativity and,

 

Lorentz Ether theory, possibly a bit misnamed, as what has come to be known as Lorentz Ether theory isn't exactly what Lorentz proposed.

It posits that moving objects actually do morph and slow down, but they do it in such a way that it is completely undetectable and that there is no way you can know which object is slow/squished and which one is stationary. It also posits a completely undetectable Ether which defines a completely undetectable rest frame.

 

Of these two, special relativity is the least hairy. It is also compatable with general relativity, which explains gravity -- I do not know whether anyone has put the time/effort in to make a variant of Ether theory which explains gravity. I imagine it would be hugely convoluted and even more difficult than GR. Also I'm not sure if the principles quantum physics would make any sense in Ether theory.

[owl]

Cap 'n R:

The aim is to show that two events (the light hitting the walls) occur simultaneously from one perspective (mine) but not simultaneously from another perspective (yours, standing next to the tracks). Is that not clear?

 

It is very clear. My argument and this thread topic distinguishes what is actually happening in the real world from the variables from different FORs describing such happenings. So, you, at rest with and in the middle of moving car, between the two lights, will have the advange for accuracy over me, not at rest and in the middle of the observed phenomena.

 

Sorry, but I was frustrated when I said the following and mis-spoke:

"I see a lag between one light hitting the wall and the other..."

As we have agreed before, the great mystery of constant ‘C’ is that your motion in the train and my stationary position makes no difference to when light is seen by either.

 

The forum topic challenges the reality of changing shapes and distances between objects due to changing FORs. Now we must deal with the assertion of relativity, as you said:

 

.

..Since simultaneity is relative (a logical consequence of the constant speed of light

 

Me (to another respondent):

Cap 'n R has not "proven" that relative simultaneity is a logical consequence of a constant speed of light...

 

Please detail the logic from, “The speed of light is constant" (agreed) to "the relativity of simultaneity." (I disagree.")

 

We know that things happening at the same time in different locations are not simultaneous for observers in different FORs. This is why you say that simultaneity is relative. But they are still simultaneous regardless of from where and when they are observed. What is happening on Earth and on the Sun is all happening right now, not dependent on when we see, say a certain solar flair, which of course will be over 8 minutes after it happened.

Cap 'n R:

In very explicit words: If the wall is moving towards the light, the light will reach the wall sooner. If the wall is not moving towards the light, the light will reach the wall later. In different reference frames, the light never changes speed; the wall does.

 

Is that not clear?

 

Yes, very clear. I understand English much more easily than trying to translate the meaning of graphs into a real -world scenario. Thanks.

 

Will you please address my take on simultaneity above in equally clear English. Then maybe we can move on to your conclusion as pertains to length contraction.

 

Schrodinger's hat;

 

Very close. According to SR, distance is not an invariant.

It's not a frame independant qauntity

 

Now we are getting "down to it" for realism vs idealism. SR says that since lightspeed is constant, distance traveled must not be invariant in certain situations... i.e., "length contraction."

Realism argues from concrete situations, saying that the Earth-Sun distance does not vary with the frame of reference from which it is measured. In the real cosmos, bodies do not move closer together and further apart each time the distances between them seem to vary as measured from different FORs.

What say you?

Edit, Ps: Another way to put the realist argument was my thought experiment, which you said made no sense to you. What part of this do you not understand?:

Without intelligent life in the cosmos, it would not be drastically different on cosmic scale. Without measurements, things would remain as they are, aside from the catastrophe perpetrated upon Earth by "civilization."

Earth would have the same orbit around the Sun, varying only a little in distance between bodies with position in its elliptical orbit.

Edited September 16, 2011 by owl

[Cap'n Refsmmat]

We know that things happening at the same time in different locations are not simultaneous for observers in different FORs. This is why you say that simultaneity is relative. But they are still simultaneous regardless of from where and when they are observed. What is happening on Earth and on the Sun is all happening right now, not dependent on when we see, say a certain solar flair, which of course will be over 8 minutes after it happened.

You are still conflating light delay (the time it takes for us to see things) with relativity of simultaneity. The eight-minute delay in the travel of light from the Sun to the Earth has absolutely nothing to do with relativity of simultaneity as presented in special relativity.

 

In my example, what is happening in the railcar depends exactly upon whether you're moving relative to it.

 

Your dictum has been to measure events in the frame in which they are at rest -- e.g. events are simultaneous when you're standing on the railcar, in its reference frame, so they must remain simultaneous. What if the two walls of the car are moving in different directions? How do you decide which reference frame is correct?

[Schrödinger's hat]

Now we are getting "down to it" for realism vs idealism. SR says that since lightspeed is constant, distance traveled must not be invariant in certain situations... i.e., "length contraction."

Realism argues from concrete situations, saying that the Earth-Sun distance does not vary with the frame of reference from which it is measured. In the real cosmos, bodies do not move closer together and further apart each time the distances between them seem to vary as measured from different FORs.

What say you?

 

This is close to what I'm trying to say, although the conclusion is different.

I'll use angular size as an analogue again.

The angular size of the moon is part of reality. It's not subjective, if you go out and measure it I can predict before hand what value you will get, but do do this I need some information:

Your location (and your velocity if we're taking into account aberration and/or relativity, but ignore that for now).

If I input your location relative to the moon into the laws of classical optics I will get the angular size you measure. (to within accuracy of tools that are likely to have. If you have a really precise apparatus I'd need to include factors like velocity, temperature and pressure of the air, altitude and so on).

 

In SR distances fall into the same category.

From where I'm sitting, with measurements I could make of some objects. No matter your FOR, I can predict any distances that you measure relating to those objects with one piece of information:

Your velocity (either relative to the objects, or relative to me -- from one I can work out the other).

 

There is a concept known as proper distance which is invariant. Ie. Earth's proper radius if you assume it's not spinning (or is spinning so slowly that it doesn't matter -- which is true) and ignore GR is: 6370 km (this may work for or there may be a similar property which works for spinning objects, but I do not know. Rotating things require maths more similar to that used in GR than SR). I can predict this from any frame of reference if I take measurements of the times and places of events that happen on Earth in my frame.

 

But not all objects or arrangements of objects have a proper distance.

To illustrate let's imagine we have some objects carefully arranged (I'm imagining performing spaceships in the relativistic equivalent of an air-show just for kicks) so that they came from lots of different directions at velocities close to c and were all in a straight line for a moment.

 

This line they make for that moment is a real object, if they had robust enough hands they could reach out and high-five each other so that they were all connected for a nanosecond.

But which velocity do we use to measure this? The line isn't moving in any particular direction. There are plenty of other situations, what is the area of a triangle made up of three objects with different velocities?

Edited September 16, 2011 by Schrödinger's hat