Motor Daddy
Valued Senior Member
Statement 1 is correct, and my method is 100% in accordance with that statement. Statement 2 is actually what you and SR believes, whether you realize it or not.
The Relativity of Simultaneity
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Statement 1 is correct, and my method is 100% in accordance with that statement. Statement 2 is actually what you and SR believes, whether you realize it or not.
Motor Daddy
Valued Senior Member
Again, light always travels at c. Objects can also travel during the same duration of time. Does that change the speed of light? NO!
In the cube, light has to travel a distance to reach the receiver. If the receiver "runs away" from the light, the light has to travel a greater distance and time to catch it. That doesn't mean the speed of light changes, it means the distance and time are greater to reach the receiver, which means the measured speed of light is not c due to the motion of the receiver and source.
Except that if the receiver is length contracted and time dilated, it won't notice any of this, and the end result is that it still measures the speed of light to be c even though it "shouldn't".
That's the whole point. Actual experiments that "shouldn't" find light traveling at c, because the apparatus itself is moving, measure it traveling at c anyway. SR offers an explanation of this observation in terms of the laws of physics possessing a particular symmetry property.
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Motor Daddy
Valued Senior Member
Well maybe you can help James?
Let's discuss one aspect of the diagrams at a time, so that we can identify each problem separately.
In your diagram on the left, Einstein's embankment frame, you show that the embankment observer thinks light traveled .5 seconds to travel from the source at the midpoint of the train to the receiver attached to the side of the train, which is .5 light seconds from the source.
James, that is incorrect. The embankment observer will see that the receivers on the sides of the train have moved to the right in the diagram, as the receivers on the sides of the train are affixed to the train, and the train has traveled to the right in your diagram. So, in the bottom pic of your left diagram, the light has not yet reached the side receivers at the midpoint of the length of the sides of the train. In other words, in Einstein's embankment frame, the light can't possibly reach the side receivers in .5 seconds, because light has to travel a greater distance than .5 light seconds to reach them. The radius lines of the light sphere from the center of the sphere to the point the receivers are attached at the midpoint of the length of the train will be at an angle to the right, which means the radius lines are longer than .5 light seconds in length.
Please explain that before we continue.
I've attached a pic to show the distance the light has to travel to reach the side receivers, of which the light has clearly not reached yet. Also note, that if the light sphere needs more time to expand to reach the side receiver, the train is also traveling to the right, so the time is even greater, as the angle increases. The light sphere will grow outside the train's front before the light reaches the sides.
Err, no, statement 2 is what you hallucinate that SR claims. SR doesn't say such an idiocy but you believe that it claims that. No one can have any control over your hallucinations.
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Motor Daddy
Valued Senior Member
You say the speed of light is always measured to be c, regardless of the frame in which it is measured? Then that is EXACTLY what you are saying!
Based on your 1200+ posts, you have no clue what "frame" means.
Yep, in VACUUM. This is also what most sensible people say (this excludes you) and this is what experiment confirms.
I have no control over your hallucinations to the contrary.
Motor Daddy
Valued Senior Member
So you think that regardless of the motion of a source, the light will always be 299,792,458 meters in front of the source 1 second later.
If a train is in motion going down the tracks, and a light is emitted at t=0 at the rear of the train towards the front of the train, and the light reaches the front of the train at t=1, how long is the train??
It is painful to have to learn from such social misfits, lol. But no pain, no gain. Forum abuse is the layman's form of academic rigor to get to the bottom of something. I stick with things until I understand them. MD apparently does the same. For that I commend him. To ridicule us for our efforts to understand and learn makes you trolls regardless of how dumb you say I am. You weren't born smart
guys were you?In the FRAME of the source, yes. You need to learn about frames of reference.
Motor Daddy
Valued Senior Member
You don't even understand what you are saying!
You are saying that regardless of the motion of the source, the light will always be 299,792,458 meters in front of the source 1 second later. You are saying you agree with statement #2 and you don't even realize it.
The source is a distance away from the point of emission, and the light is a distance away from the point of emission. They are each a distance away from the point of emission at t=1.
No, this is a strawman. Relativity does not say this:
What relativity does say is that, from the point of view of an observer moving along with the source, the light travels a distance of about 1.732 light-seconds and takes 1.732 seconds to do it. Dividing the two you find that the light still travels at c as measured by the moving observer. The factor of $$\sqrt{3} \approx 1.732$$ is the relativistic Doppler shift factor.
To ridicule us for our efforts to understand and learn makes you trolls regardless of how dumb you say I am. You weren't born smart
No one was born educated that takes time. This is accomplished by assembling facts and knowledge. Ignoring the facts and data because it does not fit with your preconcieved ideas is not only counter to an education it is in fact a dumb way to conduct yourself. QW, I really don't know about you, but i do know the MD is consistently and purposefully dodging the fact that light is always measured at c in a vacuum. He knows that light is always measured as c and that this destroys his pet idea, because you can clearly see him weasel out of having to admit this. I don't find anything about this type of attitude commendable it is really rather obscene. Everybody is ignorant of some things but to be willfully ignorant and then pound your chest stating how smart you are is delusional. Rather frightening really...:bugeye:
The only consolation is that you'll never figure this one out.
Motor Daddy
Valued Senior Member
Are you gonna help James?
So the observer is riding the source. At t=0 the source emitts light. At t=1 the source and observer are 100 meters from the point in space the light was emitted, so the source and observer had a 100 m/s velocity in that one second. At t=1, the light MUST be 299,792,458 meters from the point in space it was emitted, which means light traveled at c. It also means that the light is only 299,792,358 meters in front of the source and observer, so according to the observer, light only traveled at 299,792,358 m/s, as the observer fails to acknowledge his own velocity of 100 m/s in his calculations.
So the observer is riding the source. At t=0 the source emitts light. At t=1 the source and observer are 100 meters from the point in space the light was emitted, so the source and observer had a 100 m/s velocity in that one second. At t=1, the light MUST be 299,792,458 meters from the point in space it was emitted, which means light traveled at c. It also means that the light is only 299,792,358 meters in front of the source and observer, so according to the observer, light only traveled at 299,792,358 m/s, as the observer fails to acknowledge his own velocity of 100 m/s in his calculations.
Why? He's doing fine.
A thousand posts into a thread about relativity, and you're still talking about frame dependent quantities in absolute terms? Who's idea of t = 1? Who's idea of 100 metres? Observers with different relative velocities don't agree on the length of the second or the metre. If you haven't picked this up by now, there's no hope for you.
Motor Daddy
Valued Senior Member
No he isn't. Maybe you can answer the question to save him some time?
Yeah, seeing how I'm saying there is absolute distance and time in a world of absolute velocity.
I'm not talking about two observers. There is one observer, and he is riding the source. Are you trying to say the light is more than 299,792,358 meters in front of him at t=1, or are you trying to say he is at the original point of emission at t=1, and the light is 299,792,458 meters away from him?
How far is the source and observer away from the original point of emission at t=1?
MD, I tried to approach the question from the standpoint that time dilation and length contraction must have physical causes and have encouraged a discussion along those lines once or twice with no response. From what the smart guys are saying, when you observe light you have to consider your motion relative to that point of emission, but is your relative motion then the cause of SR time dilation and length contraction.
Someone correct me if I'm wrong when I say that time dilation and length contraction are attributed to the relativistic Doppler effect.
Now I have a lot to learn about that but I am not yet understanding how motion alone can cause time dilation. I would find gravitational time dilation easier to understand because (or maybe if) it is that energy density increases as the strength of a gravitational field increases. But in SR there is no gravity and no gravitational change in energy density even if that did have anything to do with gravitational time dilation.
I must say I understand how the relativistic Doppler effect would change the wave length (and frequency) of light but not how it would cause time dilation and length contraction.
I'm open to more forum pain if someone wants to ridicule me for asking about that. Better yet why not just tell me without all the pain, lol.
Someone correct me if I'm wrong when I say that time dilation and length contraction are attributed to the relativistic Doppler effect.
Now I have a lot to learn about that but I am not yet understanding how motion alone can cause time dilation. I would find gravitational time dilation easier to understand because (or maybe if) it is that energy density increases as the strength of a gravitational field increases. But in SR there is no gravity and no gravitational change in energy density even if that did have anything to do with gravitational time dilation.
I must say I understand how the relativistic Doppler effect would change the wave length (and frequency) of light but not how it would cause time dilation and length contraction.
I'm open to more forum pain if someone wants to ridicule me for asking about that. Better yet why not just tell me without all the pain, lol.
Now here might be something on the cause I am looking for. Is it? Is that similar to the Lorentz invariance factor, if I have the terminology right?
You reveal the exact opposite in your next statement:
You're not presenting a challenge for relativity then. You're simply denying it. What you say above is exactly what everyone believed in the nineteenth century and before. It's what everyone was probably born believing.
So the question is, why should everyone believe you, when you say something that we all used to believe but have since had good reason to abandon? Why should everyone believe you when you say distance and time are absolute?
Answering this seems a bit pointless. At t = 1 in the observer's rest frame, the light is 299,792,358 meters in front of him. These qualifiers are necessary because in SR, where distance and time are explicitly not absolute, what the source-riding observer calls t = 1 isn't the same as what a different observer would call t = 1, and what the source-riding observer calls 299,792,358 meters isn't what a different observer would call 299,792,358 meters.
If distance and time were absolute then you'd be right and what I said above would be wrong. But there's the problem: when you say distance and time are absolute, nobody has any reason to believe you just because you said so.
Which is why answering the question was pointless. If you understood that distance and time might not necessarily be absolute then you should have been specific about whose metres and seconds you were using to measure things. If you thought that distance and time must be absolute then you should have explained why we should believe that, when we have good evidence to the contrary, instead of asking a question that presupposes it. So either way your question was pointless and only demonstrates your misunderstanding of SR.