The Relativity of Simultaneity
- Thread starter Motor Daddy
- Start date
Motor Daddy
Valued Senior Member
Curiosity implies interest in the unknown. I thought you said you weren't interested?
Now you're a comedian.
In catching up with 1200 posts? Nope. Morbid curiosity doesn't imply that I would be.
No, you're a liar. I've already told you: my first post in this thread was not directed at you. You engaged me in conversation, not the other way around.Now you're a comedian.
No need to bother. The previous 1200 posts are the same nonsense MD posts all the time. Nothing changes, he just keeps repeating himself.
Motor Daddy
Valued Senior Member
No, in clicking on the thread. Try to stay focused.
I said it's rude of you to enter a thread you haven't read and start asking questions. I didn't say your first reply was a question, nor did I say you engaged me first, what do you pretend I'm lying about?
Facts:
1. You entered the thread without reading it.
2. You asked questions.
3. That is rude!
I am. Apparently I was curious enough about the thread to click on it. So I clicked on it. But I've said nothing to imply I was interested in catching up with the first 1200 posts in the thread. And accordingly I haven't caught up with the first 1200 posts in the thread.
Try to stay focused.
You were lying by omission.
Motor Daddy
Valued Senior Member
Do plan on contributing any good information, or are you just here to be a distraction? If it's just to be a distraction, I'm done replying to you.
I get your point. And would you mind confirming for me that you came up with your own postulate (which you said I understood) because you read Part I of http://www.bartleby.com/173/ and you were motivated by the kinds of things you just mentioned.
As I stated earlier:
MD introduced the concept of a moving light box to clarify his objection to the second postulate.
He assumes he is in an inertial frame of reference in which a flash of light is propagated at a point and time in absolute space without knowledge of the motion of that frame relative to the point in space and time where the propagation took place.
He assumes that the point of propagation of light occurs at a fixed point in space at a fixed time regardless of the frame of reference.
MD’s Box lays out an alternative postulate. Light propagates at c from the absolute point in space where it is propagated.
My point at the moment is that you have read and interpreted SR on your own from the actual text, and you are interested in ...
Tell me your exact objective at this point in time regarding this thread, where you would like it to go?
Neddy Bate
Valued Senior Member
Alright, so let's get back to my question. Let's say the speed of the cube is 0.80c along the x-axis, and there is no y or z component to the velocity. The distance relative to the cube is 0.5 lightseconds in both directions, AS MEASURED WITH MEASURING BARS, so I think you would predict the one-way times to be like this:
t_forward = 0.50 / (1.0c - 0.8c)
t_forward = 2.50 seconds
t_backward = 0.50 / (1.0c + 0.8c)
t_backward = 0.28 seconds
t_total = 2.50 + 0.28 = 2.78 seconds
Thus, using the "round-trip" times, the speed of light inside the cube would be measured to be:
c_measured = 1.00/2.78 = 0.36c
Now could you please explain why we always measure the speed of light to be 1.00c on earth (which is not at absolute rest), and not a variety of different numbers, such as 0.36c?
I think he agrees.
I'll look forward to MD's answer but I would like to say that your are not providing an experiment that is proiperly set up in regard to MD's postulate. He emits a flash from within the box. Are you using a flash from Earth? He believes the flash travels at c from the instant and from the point of emission. Is that circumstance included in your reference to the measurement of the speed of light from Earth? Just trying to avoid miscommunication. The test should be of his postulate using the rules of MD's box.
I am facilitating and not playing MD's first mate, lol.
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Neddy Bate
Valued Senior Member
Consider that the earth is in motion relative to the sun at approximately 29.8km/sec. MD's theory claims that the speed of light on earth is a function of earth's "absolute speed". So MD's theory predicts that the speed of light on earth should vary by something on the order of 29km/sec throughout the year.
There are countless experiments which do not support this idea. Here is one:
http://en.wikipedia.org/wiki/Speed_of_light#Increased_accuracy_of_c_and_redefinition_of_the_metre
"...a group at NBS in Boulder, Colorado determined the speed of light in vacuum to be c = 299,792,456.2±1.1 m/s."
Do you see the plus/minus tolerance at the end of that value? It says "±1.1 metre per second". Why doesn't it say "±29,800 metres per second, depending on the time of year the experiment is performed"? This supports Einstein's second postulate. How does MD's theory explain this?
Neddy Bate
Valued Senior Member
Those numbers come from using MD's own rules for the box.
The only reason I mention earth in the last sentence is because the earth is surely not at absolute rest. So, why do the principles of MD's box not materialize in tests on earth?
I glad you asked. It is true that the motion of Earth changes relative to the light from the sun, and I think it would vary not just yearly, but daily is you measure in the morning vs. in the evening, or am I wrong on that?
Anyway, you have been following the thread longer than I have and so I thinking I missed that claim. Are you sure he said it that way or did you interpret that from his statement about the moving light box and apply it to the Earth?
As far as I can tell, the fact that Earth moves toward and tilts toward and away from the earth throughout the year does not provide a test of the postulate.
Because the light that he is using in the box was emitted from the center of the box and that center point becomes the center of expansion of the light sphere.Those numbers come from using MD's own rules for the box.
Neddy Bate
Valued Senior Member
If the tests are done on the equator of the earth, and if MD's theory is correct, then I would expect to see about a 0.5 km/sec variation in the speed of light, as tested throughout the day. But I would expect the variation to be even larger throughout the year, because the orbital speed of the earth around the sun is about 29.8 km/sec.
I interpreted it from his claims about the speed of light relative to the inside of the box.
I'm not talking about using sunlight to test the speed of light. I'm talking about tests performed on the surface of the earth which find the speed of light to be constant throughout the day, and throughout the year. If MD is correct, then I would expect these tests to reveal the earth's motion. But they do not. MD should try to address this, because it is strong evidence against his theory.
Motor Daddy
Valued Senior Member
I won't be at my computer for a couple days so I won't be able to respond. I'm on my phone now. I'll read, but wait until I get back to my computer to respond.
I understand what you are saying and certainly appreciate and respect your view of those circumstances as a valid test of MD's postulate.
You're going to think I am nit picking but here is my take on whether the motion of the earth is going to show up. Let me see if I understand. You are doing an experiment to test MD's postulate. You set up a light source. You emit a flash. Then you take the position that the motion of the earth relative to the fixed point in space where the emission of the flash took place is representative of MD's moving box. Correct so far?
Then from that point MD has sensors set up at 1/2 light second distances, the box is moving in rectilinear motion in a straight line along one axis, and the light specifically from the flash is received by the sensors. You have calculating that there should be a measurable MD effect and you are saying that there is no difference in the measured speed of light. Am I right so far?
Ned, I'm not trying to put up straw men in front of you because I do think I see your point and I don't think you are testing MD's postulate as much as you are applying human logic to the postulate and concluding that it is easy to falsify. I'm not disagreeing with the human logic, but I am trying to facilitate. If you don't duplicate MD's rules in the experiment he is going to respond with what might seem like a dumb and unresponsive response
. But if you were to duplicate the rules and he were to agree with the set up and the readings on the sensors, and still not acknowledge the human logic of you rigorous experiment, I wouldn't waste my time facilitating.
Who needs you, lol. Just kidding; I'll try not to get the thread closed or moved until you come back.
I've drawn a diagram that shows the speed of light towards a mirror is nearly infinite, and the speed of the reflected light is nearly zero.
This diagam, and two numbers, supports the theory that you never see a reflection in a mirror unless you are traveling at infinite velocity towards it.
So since you do see a reflection in a mirror, you must have infinite velocity.
Now, who wants to prove my theory is wrong? Remember, I have a diagram.
Don't make me use it. It will rock your socks.
This diagam, and two numbers, supports the theory that you never see a reflection in a mirror unless you are traveling at infinite velocity towards it.
So since you do see a reflection in a mirror, you must have infinite velocity.
Now, who wants to prove my theory is wrong? Remember, I have a diagram.
Don't make me use it. It will rock your socks.
While MD is away, the mice will play.
I’m going to take a minute and expound on MD’s postulate and the moving box scenario. He can correct me when he returns but I think that there needs to be more specifics in order for the smart guys to falsify it. I feel like you, all of the eight or ten, who are following closely and are interested in falsifying MD. Some of your arguments are that he has been falsified by scientific experiment and he (and I am) is (are) too dumb to see the obvious.
Then be more obvious. Link us to an experiment that fits the rules specifically (not just essentially), discuss what would be a valid experiment, or just offer a thought experiment in accord to the postulate and rules that he has utilized to do his math.
This is how I understand the postulate and moving box scenario:
The box looks like this:
The earth is not in the box. If the earth was in the box it would move with exactly the same characteristics as the box and not with the characteristics that are displayed by the real motion of the earth.
Space is empty except for the flash and the box.
There is a light flash emitted from the center of the box at an instant in time. The flash sticks to the point in space where it was emitted and expands spherically from there at c relative to that point in space.
The flash is not just a photon at every point around the sphere. It has enough duration to be detected, i.e. there are enough wave crests with enough frequency to be detected by his sensors. The waves are the kind of EM that one would expect to be emitted by a flash from a body at rest under the terms of SR. It is true that MD’s box is immediately not at rest relative to the point in space of emission, but we assume that the flash was properly emitted from “at rest” in SR’s perspective; the light sphere is expanding spherically at c.
This light flash is also exactly the kind of EM that would be encountered by an observer in a frame of reference moving at relativistic speed relative to the point in space where where the flash was emitted.
If there was anything in the make up of the box that would absorb spectral lines and if the light that is observed in your experiment has passed through the box and out into space then the light would be red or blue shifted according to the difference in the observers speed relative to the fixed point in space. Everything about the light waves would be according to the expectations of known science.
You would know the frequency and an expected time of arrival of MD’s flash. There is no reason you would observe it or measure it unless you were looking for it, but say you had the same receptors as MD has in his box and were looking. You would know the point in space of the emission, you would know the number of wave crests emitted, and you would know the point in time of the emission, everything that MD’s on-line computer knows. Then you could receive the specific light box flash on your own receptors and your computer would record the appropriate data.
MD has a perfect clock. This is not one of those clunky cesium clocks, it is a perfect clock and it measures time in a unit of measure compatible with the box and the motion of the light wave. It assumes the light wave was emitted from a specific point in space, at a specific point in time, with a specific number of wave crests and valleys, with a specific wave length, and that the precise Doppler Effect is expected to be observed based on the relative motion of the observer which is known. MD might object but he is gone right now, lol.
The on-board computer has adjusted for the precise motion of the box and can perform all of the SR calculations. It knows what the recorded data says in terms of the duration of time measured by MDs perfect clock on board. It knows the clock is in motion relative to the fixed point in the rest frame in SR and can adjust for known SR time dilation at the particular relative speed. It calculates the motion of the box using the data and a rule (law) below:
The law is that the light sphere has traveled faithfully at c in the rest frame and that it is the exact same light sphere that will be recorded on the box's receptors. This is a violation of SR if you consider the box to be a different frame from the emission and if you believe that the light sphere will act differently in SR than in MD, but it is in line with MD's postulate.
The on-board computer can do the Lorentz adjustments and give the expected SR results as to what the present location of the box should be, the motion of the box since the flash, and the length contraction and time dilation expected based on the calculations based on the relativistic Doppler Effect. It can calculate what time the clock should say and can adjust the data reading received and recorded to determine if the appropriate time passed according to SR.
The on-board computer can also go into a “consider yourself at rest mode”. That means that it can adjust all of the data to faithfully go back to the at rest position at the center of the light sphere and tell us exactly how long it has been since the flash so it can compare that to the on-board clock. We are not expecting any time dilation or length contraction but it will give us a set of data and exact predictions. If the results are not in accord with the predictions then MD was not correct. Let’s say that there is a tolerance of a small amount but not enough tolerance to make the results inconclusive if the motion is as SR predicted it.
Don’t say it, lol, I know I just wasted my time from the perspective of most of you, but I just thought there should be some more details.
What do I think the results of MD’s scenario would be in real life? Let’s go to what the box’s on-board computer would say if MD was correct:
It knows if the results are compatible with SR because it knows SR rules and does the appropriate SR calculations. It knows if the results are compatible with MD because it knows MD rules and does the appropriate MD calculations. If MD is correct the on-board computer will tell us that the light sphere was recorded to be expanding at c from its point of emission in the rest frame, and it will tell us that the results agree with MD’s predictions of the speed of the box.
If MD is wrong the on-board computer will tell us that the light sphere was detected to be expanding a c from its point of emission in the rest frame which both SR and MD predict. The on-board computer would be able to tell if the predicted time dilation and length contraction occurred as predicted at the exact relative speed of the moving box frame after appropriate adjustment and could then say the MD was wrong and SR was right.
It is a thought experiment because MD does not propose that it can be tested because we don’t have a light box to test it with.
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