Motor Daddy
Valued Senior Member
I have to go now. That will give you some time to think about it. See you soon.
The Relativity of Simultaneity
- Thread starter Motor Daddy
- Start date
See the last post on the previous page.
I'm working under the assumption that the embankment is at absolute rest, because I thought you would be able to grasp that intuitively.
When I talk about times, I'm talking about absolute times as defined by embankment clocks, and when I talk about distances, I'm talking about absolute distances as defined by embankment rulers.
I am not going to talk about times or lengths in the train frame for some time yet.
First, I will show what measurements can and can't be made by the train observer.
Then, I will construct the measurement framework that we call the train frame.
Then, I'll show that in that frame, embankment rulers are measured to be short, and embankment clocks are measured to run slowly and out of sync.
But one step at a time.
Good night.
I'm working under the assumption that the embankment is at absolute rest, because I thought you would be able to grasp that intuitively.
When I talk about times, I'm talking about absolute times as defined by embankment clocks, and when I talk about distances, I'm talking about absolute distances as defined by embankment rulers.
I am not going to talk about times or lengths in the train frame for some time yet.
First, I will show what measurements can and can't be made by the train observer.
Then, I will construct the measurement framework that we call the train frame.
Then, I'll show that in that frame, embankment rulers are measured to be short, and embankment clocks are measured to run slowly and out of sync.
But one step at a time.
Good night.
Might I assist? To reach some agreement in this discussion might I suggest that you say that all clocks are light clocks, and that all rulers and other solid bodies are electromagnetic in nature.
"This might seem like an odd sort of clock, but consider the standard definition of a second, which is 9,192,631,770 periods of the radiation corresponding to the transition between the two hyperfine levels of the ground state of the cesium 133 atom.3 If we regard the cesium atom as a kind of optical cavity which resonates at the prescribed frequency, then this is quite similar to our sonar clock. Consider also the definition of the meter, which is the length of the path traveled by light in vacuum during a time interval of 1/c =1/299,792,458 of a second.3 So we do in fact equate length with wave propagation time just as our hypothetical sailors do, and the quantity c is simply a unit conversion factor".
Think about what you'd measure if you were in essence "made of sound". See The Other Meaning of Special Relativity. It talks about matter waves, gives the analogy of a submariner using a sonar clock, and says:
"This might seem like an odd sort of clock, but consider the standard definition of a second, which is 9,192,631,770 periods of the radiation corresponding to the transition between the two hyperfine levels of the ground state of the cesium 133 atom.3 If we regard the cesium atom as a kind of optical cavity which resonates at the prescribed frequency, then this is quite similar to our sonar clock. Consider also the definition of the meter, which is the length of the path traveled by light in vacuum during a time interval of 1/c =1/299,792,458 of a second.3 So we do in fact equate length with wave propagation time just as our hypothetical sailors do, and the quantity c is simply a unit conversion factor".
Motor Daddy
Valued Senior Member
Good, so one clock can't run slow, because it has nothing to compare to. It ticks, that's it.
Are you saying the train observer can use the embankment's clocks to compare to?
That's strange, first you say the train observer has no way of knowing if he has a velocity or not because he isn't aware of the embankment, but then you change the story and say the train observer can compare his clocks to the embankment's clocks. Which is it, Pete, is the train observer aware of his surroundings (ie embankment and tracks) or is he clueless?
By the way, when you say a clock runs slow, you really mean that another clock is the standard, and the "slow" clock is substandard.
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My point is that apparently you do not understand that! You stated:
Actual experimental measurements show your conclusion to be wrong.
The light will move at 299,792,458 meters/sec relative to the train so the light will be 299,792,458 meters in front of the train 1 second later.
What is your evidence that this is not correct. Beside your 'gut feeling' that is.
Motor Daddy
Valued Senior Member
Really, is that what experiments show?
So let's get this straight. A train is traveling down the tracks at .5c. As soon as the front of the train with a headlight aligns with a line on the tracks the headlight turns on. How far from the line is the front of the train after 1 second? How far is the light from the line after 1 second?
Motor Daddy
Valued Senior Member
Correct, so the light is 150,000 km in front of the train after 1 second, as I already explained. Origin is the one struggling.
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Yes.
It is rather simple to calculate how far in front of the train the light will be from the reference frame of the train, so lets do that. The speed of the light relative to the train is 299,792,458 meters/sec. So lets do the math:
299,792,458 meters/sec X 1 sec = 299,792,458 meters
The light will be 299,792,458 meters in front of the train in the train's reference frame.
Motor Daddy
Valued Senior Member
You didn't answer my questions:
How far from the line is the front of the train after 1 second?
How far is the light from the line after 1 second?
We are using the tracks in this thread as the tracks, which have already been tested with light to be zero velocity.
Answer the questions.
You might try asking questions that weren't already couched in terms which cater only to your preconceptions.
Motor Daddy
Valued Senior Member
No preconceptions about it, by definition a meter is inseparable from a specific amount of light travel time.
The tracks were tested and found to be a zero velocity. There is only one correct answer for each question. Care to take a shot?
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Motor Daddy, I do not want to invoke any of that pesky relativity that you have a problem with.
Lets stick to my initial point that I have made several times. I maintain that you are basing your analysis on a faulty assumption. You have said that the relative speed of light is affected by the motion of the source which is vital to your analysis. I and 100 years of measurements say that is wrong. I have asked numerous times for any evidence that the relative speed of light is affected by the movement of the source.
You will not cite any sources which leads me to believe that you have no sources and are simply arguing for, I don't know the fun of it?
PS
Nice touch
Motor Daddy
Valued Senior Member
I never said anything about the speed of light being affected by the source. Where did I ever say that? Provide the quote! I've repeatedly said that light travels independently of objects.
Answer my questions. The questions aren't difficult. It's basically second grade math.
This is what makes me convinced you are simply jerking people's chain's for fun. You really want to go back around AGAIN on this... OK.
Here is your quote:
What you are saying is that the light is moving at 149,896,229 m/s relative to the train. That is why you think that the light will have traveled 149,896,229 m in front of the trainafter 1 second.
That is wrong.
The light will be moving at 299,792,458 m/s relative to the train.
How about this, assume the train is moving at 299,792,457 m/s and you turn on the head light. The speed of the light relative to the train will be 299,792,458 m/s. After 1 second the light will have traveled 299,792,458 m in front of the train.
You think that the relative speed of light shining towards the front of a train moving a .5c is 149,896,229 m/s (the light travels 149,896,229 m relative to the train in 1 sec). If that is true then your analysis is dead on. So all you have to do is supply any evidence that the relative speed of light is affected by the motion of the source.
Simple!
Motor Daddy does not understand or accept the concept that the speed of light is consistent in every frame. He believes there to be an absolute frame in which the speed of light is c, and in every other frame, the speed of light is relative. This belief is a consequence of rejecting the Lorentz transformation. If distance and time are in fact immutable, then by MD's thinking, the speed of light must be relative.
Yes I understand that. I am simply asking him for some evidence to back up that assertion. He certainly wouldn't base an analysis on an assumption with out any evidence to back it up. I mean that would be silly.....
I am basing my assumption that the speed of light is constant in every frame from the results of the M&M exp all the way down to the speeding ticket I got from the laser speed gun. Every test indicates that the speed of light is ALWAYS measured at c, just wondering where the data is that MD is using.
Motor Daddy
Valued Senior Member
So you say the light traveled at 1.5 c from a zero velocity line on the tracks? The train traveled at .5c for 1 second. The front of the train is ~150,000 km from the line after exactly 1 second of travel. You say the light is 300,000 km in front of the train after 1 second of travel. That means the light is 450,000 km from the line after 1 second of travel. So you are saying the light traveled 1.5c for 1 second. Is that your story?
Put the light on the tracks at the line, and when the front of the train coincides with the line and light, the light is emitted. It's the same thing, the light is 300,000 km from the line, and the train is 150,000 km from the line after 1 second of travel. The light is 150,000 km in front of the train. You say the light traveled 450,000 km/s. Prove it!
We can make it more complicated too. We can have the tracks moving in the opposite direction at .25c. That means the front of the train is 225,000 km from the line at 1 second, and the light is 375,000 km from the line after 1 second, which means the light is 150,000 km in front of the train after 1 second. The tracks, the train, and the light were in motion, each at a different velocity during the same duration of time.
But you might say, how can the train be traveling .5c relative to the tracks and be 225,000 km away from the line after 1 second of travel. The .5c was based on a measure of light travel, not on the tracks. Same as you running a 40 yard dash and someone moving the starting line back 20 yards during the race. You ran 40 yards, the line moved the opposite direction 20 yards. Do you want to say you ran 60 yards if the line moves 20 in the opposite direction? If you did say that you'd be wrong!
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Neddy Bate
Valued Senior Member
Hi Pete. I understand, and I am looking forward to watching your exercise unfold. However, I'd still like to see Motor Daddy answer the following question:
Neddy Bate
Valued Senior Member
Dear Motor Daddy,
Let's say that you are looking out the window of your home. You see a lightning strike to your left about 100 meters away. Then, a little while later, you see another lightning strike to your right, also about 100 meters away.
Would you say that the lightning strikes were simultaneous or not?
I tend to think you would say that they were not simultaneous. However, according to your own anti-relativity theory, you would never know whether they were simultaneous or not. The reason you'd never know is because you don't know the absolute speed of the earth, or the sun, or the galaxy. Without knowing those absolute speeds, you would have no way of performing those calculations you like to do.
Let's say that you are looking out the window of your home. You see a lightning strike to your left about 100 meters away. Then, a little while later, you see another lightning strike to your right, also about 100 meters away.
Would you say that the lightning strikes were simultaneous or not?
I tend to think you would say that they were not simultaneous. However, according to your own anti-relativity theory, you would never know whether they were simultaneous or not. The reason you'd never know is because you don't know the absolute speed of the earth, or the sun, or the galaxy. Without knowing those absolute speeds, you would have no way of performing those calculations you like to do.