Wondering about clock transport

I agree. I was reading this thread from top to bottom, and when I reached the post where chinglu was banned, I decided that I would have to log in just to defend the fact that chinglu was actually correct, (in this rare case). But then I read further and saw that Pete had already done so...

 

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Well, that's two and I will have to go with that. I misread or misunderstood chinglu's intent.

I am feeling like I owe him an apology when he gets back, since it was my misinterpretation that instigated the problem.

 

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Don't feel bad, OnlyMe. it was a reasonable misunderstanding.
Just another day on the SciForums soap opera!

:argue::runaway::cheers:

 

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The method is called reductio ad absurdum, so you're not able to answer.

come on.....

 

Mod note: Chinglu has been unbanned. I'm pretty sure there was more content to his posting last night that strongly implied to me he was trolling, but I am happy to admit I was wrong and apologise to chinglu for incorrectly banning him.

 

kudos, prometheus. Modding's not an easy job.

 

OnlyMe's as best as possible sounds about right. I think the easy way to understand this is to start with two parallel-mirror light clocks A and B synchronized at the same location. Then you move B away from that location, then back. In clock A the light path was always like this || whilst in clock B it's like this /\/\/\/\/\ on both the outward and back trips. The two light paths are the same length, but the number of reflections is different, so the clocks are no longer synchronised. See Simple inference of time dilation due to relative velocity along with articles on super-accurate optical clocks like this: New optical clock breaks accuracy record.

 

Can you explain why?

 

I agree, completely.., and appologize for my part in how this played out.

 

Thanks for the welcome to the forum, OnlyMe.

The clocks in my table-top example were not supposed to be synchronized.
I was using them as a prime example of improperly-related clocks.

The point is, if two clocks are touching, then they should read the same time.
(And they can easily be made to read the same time because they are not
spatially separated.)

I realize that this is a very simple condition, but it will soon become very
important; that is why I would like to have everyone in the forum agree
that two touching clocks should read the same time.

(If they don't, as I said before, then at least one of them is wrong; indeed,
the entire picture is bogus,)

 

There's still some bit of misunderstanding on your part.

If they are set properly, of course two sitting side-by-side will display the same time.

But even IF they are spatially separated they can STILL display the same time. A prime example of that is our GPS satellite system. If they did NOT register the same time, since we're as dependent on them as we are today, the military and a good deal of civilians would be in one heck of a mess!!

 

There's not much to say. If the parallel-mirror light clock isn't moving the with respect to you, you'd say the light path is just straight up and down. If it is moving, then from where you're standing, the light path has to be zig-zagging otherwise the light beam would miss the mirrors. These two public-domain images by Mdd4696 from Simple inference of time dilation due to relative velocity show it better:

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Another light clock simulation.

http://galileoandeinstein.physics.virginia.edu/more_stuff/flashlets/lightclock.swf

 

If I want to hit the mirror B, which is in motion with a laser beam, I need to shoot in the direction according to the drawing ?

 

Wow ..... wow .... beautiful!
I was struggling a lot for you to accept this.
It is a superb example for the existence of an absolute reference system.

Both Jack and Jill sees the mirror is in front of him.
Jack so that hit the mirror must "shoot" to the mirror.
Jill so that hit the mirror, have to "shoot" besides the mirror (in his right).

Lamp and mirror have the same speed and they move parallel.
Between the lamp and mirror no relative speed. (Even in case 1 or in case 2)
How do you know if they both are still in motion?
They are in relative motion, both of them, compared to the absolute reference system!

How can you determine this speed?
Using the method presented by you!

 

No, Jill doesn't shoot besides the mirror. Jill shoots directly at the mirror. The simulation show the path of the photon from the pov of Jack. From Jill's pov, the photon travels in a straight line, directly across from her.

There is no absolute reference system. We have abitrarily set Jack at rest.

 

Two things re your last remarks:
(1) If special relativity does not have absolute synchronization, then I am pretty
sure that the GPS system also does not have it.
(2) But that is actually irrelevant to the point that I am trying to get across, and
you readily agreed with that point, so I'm OK, you're OK, as far as I'm concerned.

To repeat that point for emphasis:
Two touching clocks are properly related temporally if and only if they always read the same time.

To put it another way, we can say that two adjacent clocks that read different times are not properly related, and they actually conflict with the reality that they are in the same place at the same time.

Is this clear, or just clear as mud?

 

Jack's inertial frame of reference as the one "at rest":
Jill's clock reads 10 s. Jack's clock reads 22.9 s (V=0.9c)

Jill's inertial frame of reference as the one "at rest":
Jill's clock reads 22.9 s. Jack's clock reads 10 s (V=0.9c)

That the two clocks to be synchronous, to which apply the Lorentz transformation?

 

Little muddy. Two clocks can be in the same frame of reference (same place) and "touching", not read the same time and not be in conflict with special relativity.

Examples;

• The two clock were synchronized, one clock was moved away and returned to the same location.

• The two clocks were synchronized and both clocks were moved away at different velocities and then returned to the same location.

• One (or both) of the clocks is broken or does not keep time accurately.

• Both clocks keep perfect time but were never synchronized.

Note: Many thought experiments involving time dilation and special relativity use the first example as part of the thought experiment. The classic twin paradox begins with two sychronized clocks (or twins). One travels away and back. Upon its return it has recorded less elapsed time than the clock at rest has. They begin synchronized and wind up un-synchronized (one twin has aged less).

 

I did not say that two non-matching touching clocks would conflict with special relativity.

What I did say was that such clocks conflict with reality.

As you even admitted, clocks (or twins) that do not read the same when touching are simply asynchronous (not synchronized).

If you wish to talk about twins, then look at when they are born, or when they meet again after separating; in either of these cases, if there are two touching clocks at these events, then one would be crazy to say that these clocks must not match or that the twins were born at very different times, or that they met again at different times.

To reiterate, two touching clocks can be started at absolutely the same time, and in order for them to reflect this reality, they must read the same time when they are started together. Otherwise, something is askew.