Silly Einstein

[Goldminer]

I'm afraid I can't accept that there will be any difference in either the time it takes light nor the shifting of the light between the 2 flashes observed by A or C. As a single flash of light at and only at point B there wouldn't be any shifting.

I wish there were an easy way to post newly drawn diagrams! Aardwolf , please hang in there; I can only get so many ideas into a post before it gets too confusing! Now, what I think you have overlooked is that a pulse of light has to have a duration. No duration; no light. At relativistic speeds by a source moving at one half foot per nanosecond, a nanosecond flash of light in that frame will be stretched over the distance of a half a foot in the opposite frame! Thus, from the beginning of the pulse to the end of it, while remaining at the same place within the frame, (if the pulse originating in X were to start one half a nanosecond before X reached point B in the opposite frame and end one half nanosecond after X past B) you can see that the time actually spent at point B is mind bogglingly short. Then there is the rest of the duration of the pulse as seen from the opposite frame as either approaching or leaving the mutual point of conjunction.

To me that means that both flashes propagated as spheres from point B. The momentum of ship X has no effect at all. Why would it?

Please remember, it was your idea to put one lamp in the X frame and one in the ABC frame. The two lamps have relative speed between them. The X frame sphere propagates from the X frame lamp at the center of X, the B frame lamp sends its sphere from a point centered at B. I picture each lamp “at rest” with its own frame. The light propagating from either lamp is spherically expanding at the speed of light in each respective frame. I give the aether the job of “keeping each lamp moving rectilinearly through space,” and keeping the sphere of each lamp centered on each respective lamp.

My point is that light doesn't propagate equally from all light sources if that source is moving through empty space.

Please remember that you are being ambiguous here: We just can't refer to “light propagating” per se. the question is always “relative to which observer; one at rest with the source, or one in motion that just happens to be at the same place as the at rest observer for an instant?

If moving at 0.5c it will track light ahead of it by 0.5c and move away from the light emitted behind by 1.5c.

I can't tell what “it” refers to in your sentence. Do you mean the source, or an observer? If you mean an observer; to which frame does the observer belong? An observer at the source, whether moving or not, can only observe the flash at the source the instant it originates. For observers to observe the expanding sphere at some given time and distance from the source, those observers have to be at the given time and distance from the source.

Now I understand that [consensus] relativists will be screaming at me that this is incorrect, but in my example it's the only answer. Light cannot reach points A & C from X at different times to light from B.

Please remember that you specified that X is receding from A and approaching C. When X is closer to A than C, (remember the “duration of the pulse” which I suggested we arbitrarily start just before X actually reaches B) (and the pulse is expanding in X frame at the speed of light in all directions from X in that frame, and is moving with that frame away from A and toward C)

I believe this partly stems from a misinterpretation of Einsteins 2nd postulate. If I am incorrect then why did Einstein say "...that is independent of the state of motion of the emitting body".

I believe it mainly stems from the fact that Einstein has pulled a slight of hand here. The truth is that logically; once the pulse is emitted, the state of motion of the source is no longer relevant for the next particular emission. The next pulse will be centered on where the source is when this new pulse is emitted.

We view light from stars light-years away. The truth is we have no idea where those stars are today. We only know that the light we see is centered upon the star where it was when the light was emitted! Einstein said what he did without thinking the whole situation completely through.

For a bit more clarity (I hope!) I think I should point out a contradiction in what you have posted.

You state that I was correct in stating that the light received by observers at A & C from the flashes at X & B will be seen at the same time (notwithstanding the red/blue shifting disagreement which we'll leave for this example).

Observers at X and B will see their own light un-shifted, and for the tiniest instant the other's light un-shifted, at the same time. As they pass each other, they see the other's light will first be blue shifted, then red shifted.

However, you also say this "...all observers in the source inertial frame, fixed at a given distance from the source, will all see the flash at the same time."

Yes, I am correct on this: All the observers to which I refer here are on the “surface” of the expanding sphere, the diameter of which is determined by the duration of time the sphere has been expanding since the pulse was emitted. In addition, all observers in any frame, no matter the relative speed, who also happen to be at this time and place (on the sphere) in space will observe the pulse at this same time.

As you state, X is in its own frame. Let's say X was not alone, ahead of X is ship W and behind X is ship Y. Now they are 5ly ahead of and behind X respectively, and they are traveling at the same speed so are included in X's reference frame. Now, according to your statement the light from X will reach W & Y at at the same time. Relativity as currently interpreted says it must. So we have a problem. After 5 years has passed the light from point B will reach Point A & point C at the same time.

No problem here, except now we have two more observers! Keep in mind that the process of transmitting and receiving is asymmetrical.

So we have a problem. We know and you agreed that the light from X will also reach Point A & C (although shifted) at this time.

Did I say that? Spank me!

However, according to X's frame the light should also be reaching W which is 4.5ly past A and ship Y which is 4.5ly past C. How can this be possible?

Keep in mind that there is not “the light,” there are two “lights” and two expanding spheres in your scenario. Five years after the pulses have been emitted (in absolute time) each set of observers in their own respective frames will see the pulses from their own lamps at the same time. It is confusing to try to relate Y and W to A and C except to say that when B and X are aligned, Y and A are aligned and W and C are aligned. I wish I were adept at getting diagrams uploaded to the forum!

The proper process is to relate W and Y to B which is the source in the opposite frame; and A and C to X which is the source in the opposite frame. Which is to say that B is moving away from W and towards Y; and X is moving towards C and away from A.

After five years of separation, X and B will be 2.5 light-years apart (moving @ .5c), but the un-shifted opposite going light pulses from each source will reach their respective observers in each rest frame, simultaneously at the five year absolute time. (These observers being located on 5 light-year diameter spheres centered upon each source)


After five years of separation, X and B will be 2.5 light-years apart (moving @ .5c);

There is a sphere that has expanded to 5 light years in diameter and centered upon B. All observers in the B frame, located at this distance on the surface of the sphere will simultaneously see the pulse pass by them.

There is a group of observers moving along in the X frame: formed into an identical sphere to the five light-year sphere in B; only however, in the X frame, centered upon this 2.5 light-year point (2.5 light-years from X). When X passes the point 2.5 light-years from B, the center of this circle of observers in the X frame will, for a tiny instant, coincide with the observers who are on the sphere of B at 5 light-years from B, and the at same instant these X frame observers will see the pulse from B, along with the observers on the 5 light-year diameter sphere who are in the B frame! The difference in what the moving observers see is that the spectra they see of B's light in the B pulse is Doppler shifted accordingly, since the observers on the leading edge of the moving observers' sphere observe B's light red shifted, those on the trailing edge of the moving observers' sphere observe B's light blue-shifted.

If you have followed my reasoning so far, a repeat of the above paragraph happens for a group of observers moving along in the B frame: formed into an identical sphere to the five light-year sphere in X; only however, in the X frame, centered upon this 2.5 light-year point (2.5 light-years from B). and so on.

After five years of separation, B will be 2.5 light-years from Y and 5 light-years from W. Y will observe B's blue-shifted flash 2.5 years before A observes the same flash which will be un-shifted. W will observe B's red-shifted flash 7.5 years after the flash was emitted, and 2.5 years after C sees the un-shifted flash. Einstein is right about these points (Y and W) not seeing the pulse from the opposite frame simultaneously, however this is a bit disingenuous since there are points in space where observers in both frames do see the pulse simultaneously.

.

[Aardwolf]

So we have a problem. We know and you agreed that the light from X will also reach Point A & C (although shifted) at this time.

Did I say that? Spank me!

Before I address the rest of your post are you now saying that your statement was incorrect?

[Goldminer]

. . . (snip)

Here's a simple thought experiment;

We have 3 points A,B & C in a line. We have a ship X travelling from A to C via B at 0.9c. A to B is 5 light years and B to C is also 5 light years so A to C is 10 light years. Ship X is carrying a lamp and at point B there is also a lamp. The circuit to power these lamps is not completed until ship X passes point B whereby they will both momentarily flash as it passes by on its way to C.

Now, I am absolutely certain that observers at point A and C will see both lamps flash at exactly the same time when the light reaches them from both lamps. This proves that light motion is independent of the motion of the source, however, observers aboard the ship (under special relativity, time dilation etc.) experience an entirely different reality because they will try to detemine light is propagting at c in all directions around them. Obviously there cannot be 2 realities so all special relativity amounts to is an observer only reality, not an actual reality, hence there is no need for time dilation etc. as it can all be resolved easilly just calculating the delay in the propagation of light to the observers.

. . . (snip)

You are right on at this point in your scenario except that you have introduced two sources which are in separate reference frames. A,B, C and the lamp at B are in one frame; X and the lamp on X are in a different frame. Now we have two spheres of light each expanding as centered upon each respective source. Observers at A will see the initial flash at X as red shifted. C will see X's flash as blue shifted. Where as each A and C will see the flash at B to be un-shifted.

So we have a problem. We know and you agreed that the light from X will also reach Point A & C (although shifted) at this time.

Did I say that? Spank me!

Before I address the rest of your post are you now saying that your statement was incorrect?

My defense here is that I was thinking I should say something about simultaneity in that post; and then thinking Nah, save it for later. Can't sneak nuttin' past that sharp witted Aardwolf! So, I stand by the statements about the Doppler shifting of X's light as seen by observers A and B. I disagree with you that A and B will see the pulse from X at the same time they see the pulse from B.

Y and W will see X's pulse at the same absolute time that A and C will see B's pulse, 5 years after each pulse was emitted, since distances within each frame do not change, and both pulses happened at the same time/place.

Y is approaching B and C is approaching X. The expanding spheres of the opposite frame will obviously reach these observers before reaching the in the same frame observers.

W is receding from B and A is receding from X. The expanding spheres of the opposite frame will have to expand beyond the observers within each frame in order to reach W and A. These two observers will see the opposite frame's pulse after everyone else has observed the pulses.

Y and C get the first view of the pulses, at the same absolute time, but not the same place. Then all the observers get to see their respective "in frame pulses" simultaneously. Then last but not least, W and A get to see the pulse.

[altonhare]

What is wrong with this picture:


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(Time dilation from http://en.wikipedia.org/wiki/Electromag ... e_equation)



?

In the picture we have four pairs of mirrors bouncing light signals off each other that are assumed, a priori, to be stationary. That's how the video is set up, with those 4 stationary. We have a 5th pair of mirrors in motion, also bouncing light signals back and forth.

We observe that the signal on the moving pair takes longer to go from one mirror to the next. That's unsuprising, since the signal on the moving pair must traverse a longer path to get from one mirror to the next. It has to traverse a "diagonal" path.

The problem comes in when one decides: 1 path traveled = 1 unit time. That is the standard of "time" chosen in the picture, as illustrated by the clocks at the top. Each clock "ticks" when a light signal makes it from one mirror to the next. Since the signal in the moving pair moves a longer distance, it naturally takes proportionately longer also. In the moving frame each "tick" represents a longer distance-traveled, a longer period of time, and thus there are fewer "ticks" for the moving frame.

The reason MM showed no fringe is because none of the pairs of mirrors were moving wrt each other.

[klypp]

Alton's explanation is good, except for:
"We observe that the signal on the moving pair takes longer to go from one mirror to the next."
Well, that's not what we observe.

We observe that the signals in both the moving and stationary setups hit the mirrors at the same time. We also observe - like you point out - that the signal in the moving mirrors follows a longer path. From this we conclude that the light pulse in the moving mirrors moves faster than the other pulses.

Which is perfectly OK, because we know that speed is relative to the observer. We don't live by silly rules like "the speed of light is the same to all observers" and thus have no need for time dilation nor length contraction.

[altonhare]

Alton's explanation is good, except for:
"We observe that the signal on the moving pair takes longer to go from one mirror to the next."
Well, that's not what we observe.

We observe that the signals in both the moving and stationary setups hit the mirrors at the same time. We also observe - like you point out - that the signal in the moving mirrors follows a longer path. From this we conclude that the light pulse in the moving mirrors moves faster than the other pulses.

Which is perfectly OK, because we know that speed is relative to the observer. We don't live by silly rules like "the speed of light is the same to all observers" and thus have no need for time dilation nor length contraction.

I'm watching the animation, and I'm definitely seeing the blue dot in the moving pair hit the opposite mirror after the blue dot in the stationary pair.

I'm only discussing the animation and what it illustrates.

[klypp]

Hey, you're right!

I was too focused on the light pulse being sent back and forth between the mirrors in the stationary pairs and hastily assumed that they used the exact same setup in the moving pair.
But no. What they do is sending the light pulse off at an angle and then move the mirror pair along with the pulse. This makes it look like the pulse hits the mirrors at a right angle, like in the stationary mirror pairs. But of course, this is not what happens. The pulse never hits the moving mirrors at a right angle. No trace of time dilation anywhere.

The relativists like to play mind tricks, and I have to admit that once in a while they come up with some cunning ones.

[altonhare]

Hey, you're right!

I was too focused on the light pulse being sent back and forth between the mirrors in the stationary pairs and hastily assumed that they used the exact same setup in the moving pair.
But no. What they do is sending the light pulse off at an angle and then move the mirror pair along with the pulse. This makes it look like the pulse hits the mirrors at a right angle, like in the stationary mirror pairs. But of course, this is not what happens. The pulse never hits the moving mirrors at a right angle. No trace of time dilation anywhere.

The relativists like to play mind tricks, and I have to admit that once in a while they come up with some cunning ones.

Agreed. The light pulses neccesarily have to deflect through an angle.

I never knew that was up for debate. That's kind of a no-brainer I thought. Then again, most relativists are no-brainers.

[Goldminer]

Good observations gentlemen. Now; consider that in the "at rest with the source frame" only two observers are required. One at each mirror looking towards the opposite mirror. For the argument let's place the mirrors 10 feet apart.

In the moving frame, a whole series of observers are required. Each one observes the "photon" just as it reaches "his" mirror. At the velocity of 1/2c, each observer is spaced 10 feet from the next observer as they pass the mirror to observe the oncoming "photon." The observers (as they pass) on the opposite mirror are likewise so spaced, only offset by 5 feet, relative said train of observers.

The additional angle passed 90 degrees is caused by aberration. The "photon" is still traveling rectilinear. It still takes 10 nanoseconds to travel 10 feet. There is no diagonally going "photon." If there was, it would have to exceed the speed of light to meet the real "photon" traveling rectilinearly.

All observers observe the same "photon." There is no time deregulation or space deformation. Each moving observer experiences aberration in his viewing angle. This does not affect the traverse time of the "photon."

.

[david barclay]

Goldminer, has it occurred to you that perhaps light does not itself have a speed. It light itself did or does not have an actual speed would this not solve a lot of the apparent confusion.

I think the answer to this is of considerable importance to the electric universe concept and well worth consideration.

I`m not denying the measurements made or any of the experiments performed but if it is not the actual movement of light which is being determined then it has to be something else which was obviously missed. And I do view the M&M experiment as hitting the nail on the head.

So what we are actually talking about is the apparent speed of light, our perception of light itself being in motion.

[altonhare]

Good observations gentlemen. Now; consider that in the "at rest with the source frame" only two observers are required. One at each mirror looking towards the opposite mirror. For the argument let's place the mirrors 10 feet apart.

In the moving frame, a whole series of observers are required. Each one observes the "photon" just as it reaches "his" mirror. At the velocity of 1/2c, each observer is spaced 10 feet from the next observer as they pass the mirror to observe the oncoming "photon." The observers (as they pass) on the opposite mirror are likewise so spaced, only offset by 5 feet, relative said train of observers.

The additional angle passed 90 degrees is caused by aberration. The "photon" is still traveling rectilinear. It still takes 10 nanoseconds to travel 10 feet. There is no diagonally going "photon." If there was, it would have to exceed the speed of light to meet the real "photon" traveling rectilinearly.

All observers observe the same "photon." There is no time deregulation or space deformation. Each moving observer experiences aberration in his viewing angle. This does not affect the traverse time of the "photon."

.

I don't understand. I'm watching the animation, and the blue dot moving between the moving mirrors is assuredly moving diagonally while the motionless mirrors have the blue dot moving horizontally.

[Aardwolf]

My defense here is that I was thinking I should say something about simultaneity in that post; and then thinking Nah, save it for later. Can't sneak nuttin' past that sharp witted Aardwolf! So, I stand by the statements about the Doppler shifting of X's light as seen by observers A and B. I disagree with you that A and B [I think you mean C here] will see the pulse from X at the same time they see the pulse from B.

Then unfortunately there isn't anything further we can discuss. To my understanding there is a divergence from logic and reasoning if it is expected that 2 lights flashing once at exactly the same time in exacty the same place (within a few nanoseconds) would not be seen at the same time (within a few nanoseconds) by any other observer in the entire universe. A should see them flash at the same time and so should C, W & Y. You want me to accept that the light propagates dependent on the movement of the emitter which is just plain wrong.

[Goldminer]

My defense here is that I was thinking I should say something about simultaneity in that post; and then thinking Nah, save it for later. Can't sneak nuttin' past that sharp witted Aardwolf! So, I stand by the statements about the Doppler shifting of X's light as seen by observers A and B. I disagree with you that A and B [I think you mean C here] will see the pulse from X at the same time they see the pulse from B.

Then unfortunately there isn't anything further we can discuss. To my understanding there is a divergence from logic and reasoning if it is expected that 2 lights flashing once at exactly the same time in exacty the same place (within a few nanoseconds) would not be seen at the same time (within a few nanoseconds) by any other observer in the entire universe. A should see them flash at the same time and so should C, W & Y. You want me to accept that the light propagates dependent on the movement of the emitter which is just plain wrong.

I am still working on a cogent answer to both you and David Barclay.

You want me to accept that the light propagates dependent on the movement of the emitter [when the flash was emitted, says I.] which is just plain wrong.

Yes, it is wrong according to consensus reasoning. As to being "just plain wrong" I take issue. Please explain to me how a light pulse propagates away from a source; generally conceded to be expanding at the speed of light, in a sphere centered upon where the source was when the pulse was emitted; and yet also be expanding independently of the source.

1.Is the shape of the propagation something other than a sphere? Any observer; moving or not, cannot see the sphere since only a ray from the source is available to any single observer.

Furthermore, keep in mind that an observer approaching a source experiences Doppler blue-shifting and an observer receding from a source experiences red-shifting. Observers in your X frame are either approaching or receding the B source, and vice a versa observers in the B frame with respect to the X source.

2.Thus if the two flashes, one in each frame, last for 100 nanoseconds, the sources separating at 1/2 c, will be 50 feet apart by the end of the flash (If they were concentric at the start of the flash, and measuring therefrom,) right?

3.Observers in the opposite moving frame will experience either Doppler shift or aberration, with regard to the in-frame source, right?

4.The 50 feet difference in location at the end of the flashes means a 50 nanosecond difference in duration of the opposite flash since it will take 50 nanoseconds for the distant end of the opposite flash to get back to the observer at the source, right?

5.Thus, the in-frame flash will be 100 nanoseconds, and the opposite frame flash (as seen by this same observer) will be 150 nanoseconds, right?

6.To the observers in these two frames; one flash will be shorter and un-shifted, one flash will be longer and have Doppler shifting.

I am curious how you rationalize your answer to (1.)

I think you see how I understand the situation. I understand your reluctance to believe it to be rational.

.

[Aardwolf]

My defense here is that I was thinking I should say something about simultaneity in that post; and then thinking Nah, save it for later. Can't sneak nuttin' past that sharp witted Aardwolf! So, I stand by the statements about the Doppler shifting of X's light as seen by observers A and B. I disagree with you that A and B [I think you mean C here] will see the pulse from X at the same time they see the pulse from B.

Then unfortunately there isn't anything further we can discuss. To my understanding there is a divergence from logic and reasoning if it is expected that 2 lights flashing once at exactly the same time in exacty the same place (within a few nanoseconds) would not be seen at the same time (within a few nanoseconds) by any other observer in the entire universe. A should see them flash at the same time and so should C, W & Y. You want me to accept that the light propagates dependent on the movement of the emitter which is just plain wrong.

I am still working on a cogent answer to both you and David Barclay.

You want me to accept that the light propagates dependent on the movement of the emitter [when the flash was emitted, says I.] which is just plain wrong.

Yes, it is wrong according to consensus reasoning. As to being "just plain wrong" I take issue. Please explain to me how a light pulse propagates away from a source; generally conceded to be expanding at the speed of light, in a sphere centered upon where the source was when the pulse was emitted; and yet also be expanding independently of the source.

1.Is the shape of the propagation something other than a sphere? Any observer; moving or not, cannot see the sphere since only a ray from the source is available to any single observer.

The shape is a sphere as measured from the original location of the emitter, not as measured from its subsequent movement through space. Until you accept this you cannot resolve the problem that all observers in the universe should observe two adjacent flashes at the same time from any observation point in the universe. Your answer requires that the light from the adjacent flashes are travelling through space at different velocities dependent on the emitters velocity. Sorry but that's just plain wrong.

EDIT - Doppler shifting is irrelevant to this so we can ignore for now.

[Goldminer]

1.Is the shape of the propagation something other than a sphere? Any observer; moving or not, cannot see the sphere since only a ray from the source is available to any single observer.

The shape is a sphere as measured from the original location of the emitter, not as measured from its subsequent movement through space. Until you accept this you cannot resolve the problem that all observers in the universe should observe two adjacent flashes at the same time from any observation point in the universe . . . [/quote]

If you look back through the thread,“The shape is a sphere as measured from the original location of the emitter [when the particular wave sphere was emitted], not as measured from its [the source's] subsequent movement through space” has been my premises from the very start of this thread! I am pleased that you agree with me on this.