# The Relativity of Simultaneity

Discussion in 'Physics & Math' started by Motor Daddy, May 12, 2010.

1. ### rpennerFully WiredStaff Member

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Ha ha. Get banned.

3. ### Jack_BannedBanned

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Why because you stepped over your head? How should that affect me?

Let's continue the discussion.

5. ### Motor Daddy☼☼☼☼☼☼☼☼☼☼☼Valued Senior Member

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The Earth came from the Sun, what do you make of that?

7. ### PeteIt's not rocket surgeryModerator

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MD, you said that you would leave the measurement of absolute velocity to the experts.
The experts have done the measurements using your proposed method, and always measured zero.

A basic rule of common sense is that if the map disagrees with the ground, the ground is rong.

In science, this means that if reality (ie real experiments) disagree with the theory, then the theory is wrong.

Reality disagrees with your concept of space and time. Your concept is wrong.

8. ### Motor Daddy☼☼☼☼☼☼☼☼☼☼☼Valued Senior Member

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Really? Then how do you explain light travel time being different if measured from front to rear than rear to front? Are you implying that a train has two different lengths?

Your basic map rule is wrong. If the map disagrees with the ground, the map is wrong.

9. ### PeteIt's not rocket surgeryModerator

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You still haven't done the exercises or looked up any experiments, I see.
The difference in travel time measurements can be anything at all depending on the synchronization of the clocks at each end of the plane.
The problem is that you can never be sure if your clocks are correctly synchronized or not.
Any synchronization method you use will give different results depending on your velocity.

But you're avoiding one question by raising another.
I think that means you're unable to address this issue:
• You claim that absolute velocity is measureable by simple experiments.
• The experts have done the experiments.
• Absolute velocity is always measured to be zero.
That's reality, MD.

If the map disagrees with the ground, the map is wrong.
If you think the ground is different, then show me the actual experiments that prove it.

10. ### PeteIt's not rocket surgeryModerator

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So you don't believe in time dilation and length contraction, either?
MD, you have the greatest research tool in the world at your fingertips. Use it.
Experimental basis of Special Relativity
Why do you think you know what reality is when you haven't even looked?

11. ### AlexGLike nailing Jello to a treeValued Senior Member

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MD is a long time Einstein and Relativity denier. He has a truely amazing ability to ignore experimental results in favor of his own 'reasoning'.

12. ### TachBannedBanned

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It is very easy, you can find the explanation in many introductory books.
In one direction, the light chases the end of the train car, so the equation of motion is:

c*t1=v*t1+L
where L=length of the train car, v=speed of the train car.

So t1=L/(c-v)

In the opposite direction, the light front is moving heads on towards the end of the car, so:

c*t2+v*t2=L

i.e.

t2=L/(c+v)

The same thing happens in the case of light moving E-W or W-E around the Earth:

c*t1=L+R*omega*t1 in the W>E direction

c*t2+R*omega*t2=L in the E->W direction

So, t1>t2 in both cases, while light speed is isotropic.

13. ### arfa branecall me arfValued Senior Member

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Dude, the distance light travels is determined by the length of the train. If the train has a constant length, then light travels the SAME distance; front to rear = rear to front.

The train's velocity is irrelevant. At least that's my explanation for "why the travel times are different", they AREN'T different, OK?

Of course, this is only true if you're an observer on the train; it isn't true for an external observer. I surmise that MD's confusion is related to his habit of making continual and arbitrary change of coordinates. You can't get away with that sort of carry-on, it just isn't scientific.

Last edited: Dec 14, 2010
14. ### rpennerFully WiredStaff Member

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Technically, changing your premises in midstream is not logical, a prerequisite for math or physics.

15. ### TachBannedBanned

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This is textbook physics, the train speed is KEY, if you don't know it, you can always try learning it instead of posting stupid stuff.

MD posts a whole slew of other ineptitudes but you aren't the right person to correct him.

16. ### arfa branecall me arfValued Senior Member

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Why is the speed of the train "key", and to what?

I think you're the one posting stupid stuff. But by all means, explain what the train's velocity has to do with the time it takes a beam of light to travel the length of the train. Go on, you know you want to.

17. ### TachBannedBanned

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You can't read some simple math, can you?

18. ### arfa branecall me arfValued Senior Member

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Lost for words, are we?

Not doing very well with that "explanation" either, the one you can't provide because you haven't got a clue?

19. ### TachBannedBanned

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No, because you are an idiot. Even Motor Daddy understands this subject a little better than you.

20. ### arfa branecall me arfValued Senior Member

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Keep making those ridiculous noises, it's funny in a desperate sort of way, dude.

You really don't have a clue do you?

21. ### phytiRegistered Senior Member

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The times are different, but Einstein defined them for the inertial observer to be equal!

"We have not defined a common time'' for A and B, for the latter cannot be defined at all unless we establish by definition that the time'' required by light to travel from A to B equals the time'' it requires to travel from B to A. Let a ray of light start at the A time'' from A towards B, let it at the B time'' be reflected at B in the direction of A, and arrive again at A at the A time'' ."
1905 paper, par 2.

22. ### arfa branecall me arfValued Senior Member

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The observer on the train sees light take the same time to traverse the train in either direction, which is a consequence of light having a constant speed. He assumes the latter is true.

What this is about is forming a rigorous definition of time and more importantly, distance (as traveled by light), in fact identical distances if the A and B have zero relative velocity.

23. ### Motor Daddy☼☼☼☼☼☼☼☼☼☼☼Valued Senior Member

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Which has total disregard for the train's velocity.

Einstein uses a totally fabricated system not in keeping with the concept of elapsed time and simultaneity. Maybe it's easier to use, and it does have some benefits such as GPS etc, but it is wrong for one main reason, he has total disregard for the inertial object's velocity.