d is only the distance of A and B to M.
Relative Velocity Measurement – Frame and photon
- Thread starter geistkiesel
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d is only the distance of A and B to M.
OK, good.
Now, you said:
"When M and M' are co-located, lightning strikes both points A and B.
...
Now, assume there were M' observers co-located at B and A when the lightning strikes occurred at A and B and call them A' and B'."
So, at that instant in the rest frame of M:
M and M' are in the same place,
A and A' are in the same place, and
B and B' are in the same place.
So clearly:
The distance from M' to A' (in the rest frame of M) is the same as the distance from M to A (in the rest frame of M).
The distance from M' to B' (in the rest frame of M) is the same as the distance from M to B (in the rest frame of M).
Right?
Now, you said:
"When M and M' are co-located, lightning strikes both points A and B.
...
Now, assume there were M' observers co-located at B and A when the lightning strikes occurred at A and B and call them A' and B'."
So, at that instant in the rest frame of M:
M and M' are in the same place,
A and A' are in the same place, and
B and B' are in the same place.
So clearly:
The distance from M' to A' (in the rest frame of M) is the same as the distance from M to A (in the rest frame of M).
The distance from M' to B' (in the rest frame of M) is the same as the distance from M to B (in the rest frame of M).
Right?
But you've defined the situation in the rest frame of M, and that is what informs us what the situation is in the rest frame of M'. You have used the setup in M to derive a measurement in M'.
The greater point under discussion is whether that derivation of the M' situation is correct, but first we need to agree on what the situation is in M.
So. Clearly, in the rest frame of M, the distance from M' to A' is the same as the distance from M to A, equal to d. Right?
The greater point under discussion is whether that derivation of the M' situation is correct, but first we need to agree on what the situation is in M.
So. Clearly, in the rest frame of M, the distance from M' to A' is the same as the distance from M to A, equal to d. Right?
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In the rest frame of M, when the lightning strikes:
M' is colocated with M. Right?
A' is colocated with A. Right?
B' is coloated with B. Right?
M' is colocated with M. Right? True
A' is colocated with A. Right?
B' is coloated with B. Right?
There are only true in the frame of M'.
You said:
"Now, assume there were M' observers co-located at B and A when the lightning strikes occurred at A and B and call them A' and B'."
So, when the lightning strikes at A, A' is there as well, right?
And when the lightning strikes at B, A' is there as well, right?
"Now, assume there were M' observers co-located at B and A when the lightning strikes occurred at A and B and call them A' and B'."
So, when the lightning strikes at A, A' is there as well, right?
And when the lightning strikes at B, A' is there as well, right?
Yes, from the stationary view of M' they will be there.
Then they must also be there in every reference frame.
If lightning strikes A' in one frame of reference, it can't miss A' from another point of view.
It would see if lightning strikes a point, then all would agree.
Let's speed this up.
Anyway, A' and B' are equidistant to M' and the strikes are simultaneous in M' nullifying Einstein's claims.
Each frame claims the strikes are simultaneous by the light postulate and the measure a c logic of SR.
Hence, each will experience simultaneity in different positions which is a contradiction.
What? I don't understand your sentence.
There's no use in "speeding it up" if we can't agree on the setup.
It is very clear to me that you have set this scenario up so that in the rest frame of M, the distance from A' to M' and M' to B' is the same as the distance from A to M and M to B, equal to d. It is important that we figure out why we disagree on this point, because otherwise we will of course reach different conclusions.
Take note that this is the only way that A' can meet A simultaneously with B' meeting B and M' meeting M. If A' to M' is different from A to M, for example, then A' must meet A at a different time to M' meeting M.
Special relativity then tells us that in the rest frame of M':
the distance from A to M and M to B is contracted to d/λ, and
the distance from A' to M' and M' to B' is "uncontracted" to dλ.
Yes they are.
Your wild leap of logic impresses no one.
Show me the math.
I do not really think you can handle this.
Perhaps we should stip.
It is very easy SR.
If A and B are d from M and M and M' are co-located, them and and B are d/λ from M'.
Answer yes or no.
Yea, time will tell.
It' not math at this step, it's just the basic setup. I'm really puzzling over why this is a problem.
Look - you agree that if lightning strikes A' in one frame of reference, it can't miss A' from another point of view, right?
And you agreed that in the rest frame of M', when the lightning strikes at A, A' is there as well, right?
So, it clearly follows that in the rest frame of M, when the lightning strikes at A, A' is there as well, right?
Your sentence is incomplete, but I think you meant this:
If A and B are d from M, and M and M' are co-located, then A and B are d/λ from M'.
Clearly the answer is no, A and B are d from M. Any primary school student could tell you that.
But, perhaps you meant to specify some reference frames?
Perhaps you meant this:
If, in the rest frame of M, A and B are d from M, then in the rest frame of M', A and B are d/λ from M' when M and M' are co-located.
In that case the answer is yes, given that A and B are at rest with respect to M.
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Do you agree that this is an accurate snapshot of the situation in the rest frame of M at the instant that the lightning bolts strike?
Do you see that A' to M' and M' to B' must be the same distance as A to M and M to B in that rest frame?
Do you see that A' to M' and M' to B' must be the same distance as A to M and M to B in that rest frame?
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No, I do not agree.Do you agree that this is an accurate snapshot of the situation in the rest frame of M at the instant that the lightning bolts strike?
Do you see that A' to M' and M' to B' must be the same distance as A to M and M to B in that rest frame?
The M frame is moving relative to M'.
We are talking M' as stationary.
So, length contraction applies.
Based on a one way drawing of this then yes.
So, it would appear thy are the same distance but they are not.
That is SR, it can be tricky.
good I think I havd been saying this.
So where is that picture wrong?
For example, in a snapshot of the rest frame of M when the lightning strikes, is A' to the left or the right of where it is in the picture?
But Jack, you've defined the situation in the rest frame of M, and that is what informs us what the situation is in the rest frame of M'.
You have used the setup in M to derive a measurement in M'.
And right now, we're disagreeing about that setup, are we not? So, perhaps we should agree about what the setup is in M before we decide what happens in M'?
Are you also agreeing to the first part of that post?
You agree that if lightning strikes A' in one frame of reference, it can't miss A' from another point of view, right?
And you agreed that in the rest frame of M', when the lightning strikes at A, A' is there as well, right?
So, it clearly follows that in the rest frame of M, when the lightning strikes at A, A' is there as well, right?