B SR equation seems to depend on orientation of the 'light clock'

[Dale]

I wrote a light clock app (https://joekahr.github.io/lightclock/) that allows the user to change the orientation of the mirrors. Please try it. Comments are welcome.

I like it. It seems well done to me. Thanks for sharing!

 

[PeroK]

The physics looked good to me. The things that were supposed to be simultaneous were and the things that were not supposed to be simultaneous were not.

I ran it on an iPhone

I'm using Firefox on a laptop and when the clock is moving, all four light pulses hit the mirrors simultaneously.

 

[Dale]

I'm using Firefox on a laptop and when the clock is moving, all four light pulses hit the mirrors simultaneously.

Interesting. I just tried it on a laptop running Chrome and it was good, rear mirror hits first, side mirrors second, and front mirror last, with all four returning to the center at the same time. Are you simulating the lab frame or the rocket frame? I was simulating lab frame.

 

[PeroK]

Interesting. I just tried it on a laptop running Chrome and it was good, rear mirror hits first, side mirrors second, and front mirror last, with all four returning to the center at the same time. Are you simulating the lab frame or the rocket frame? I was simulating lab frame.

Tried it on MS Edge. No luck. I just selected rocket. In any case, the clock is moving with no loss of synchonisation.

 

[Dale]

Try the lab frame instead of the rocket frame.

 

[PeroK]

Try the lab frame instead of the rocket frame.

Okay, but in the rocket frame the clock shouldn't be moving.

 

[joekahr]

Yes, but your physics is wrong! Everythings stays simultaneous in a frame where the clock is moving.

OK. I am here to learn. What did I get wrong about the physics?

Perhaps you object to not showing the light clock in its own frame when the Center Clock option is set. I address this in the FAQ under "Why does the Light Clock stay contracted and its time dilated when 'Center Clock' are selected?" Is that an adequate answer?

 

[robphy]

I wrote a light clock app (https://joekahr.github.io/lightclock/) that allows the user to change the orientation of the mirrors. Please try it. Comments are welcome.

Neat.

If you make a "circle" of clocks, the contracted arrangement in the lab frame will look like an ellipse of mirrors.
If you locate the spatial components of the reflections you get a different ellipse (with the foci locating the emission event and the reception event at the source).

The full spacetime diagram will look like my avatar.
(The animated version of my avatar appears when you click on my avatar and bring up my PF profile.)

Here are some old videos, recently uploaded to YouTube:
https://www.youtube.com/channel/UCkqNyIlz3XF6IhyYbnmoJoA

 

[Dale]

Okay, but in the rocket frame the clock shouldn't be moving.

I agree. The mirrors are not moving in the rocket frame regardless of v.

 

[joekahr]

Okay, but in the rocket frame the clock shouldn't be moving.

You will see that the light clock is not moving relative to the Rocket Frame x'y' grid, whether the 'Center Clock' is set or not.

 

[joekahr]

No - I did read the instructions before commenting.

Sorry about that. I never tested on Android. Please try on a computer, iPhone or iPad.

 

[joekahr]

The OP's question was about the orientation of the mirrors of a light clock. I noticed that my app (https://joekahr.github.io/lightclock/) had a bug that made changing the orientation difficult. It's fixed now.
I also made the Center Clock default settings more intuitive: clock is moving in the Lab frame, clock is centered in the Rocket frame.

 

[Grasshopper]

That's so cool. Interesting that the light pulses always seem to intersect at the center. That surely indicates some sort of symmetry. Maybe that length contraction applies evenly across the direction of travel.

 

[Ibix]

Interesting that the light pulses always seem to intersect at the center.

They must. You could build an arbitrarily small bomb trigger that would go off if illuminated by all four pulses at once and not if only three or fewer pulses illuminate it. If all four pulses reach the center simultaneously in one frame they must in all, because whether the bomb goes off or not can't be frame dependent.

 

[ergospherical]

They must. You could build an arbitrarily small bomb trigger that would go off if illuminated by all four pulses at once and not if only three or fewer pulses illuminate it. If all four pulses reach the center simultaneously in one frame they must in all, because whether the bomb goes off or not can't be frame dependent.

Physicists are so dramatic — there's always got to be explosion of some sort
What's wrong with a little electronic counter; I mean, it'd probably be cheaper...

 

[robphy]

That's so cool. Interesting that the light pulses always seem to intersect at the center. That surely indicates some sort of symmetry. Maybe that length contraction applies evenly across the direction of travel.

Check out the videos of the "circular light clocks" linked from my earlier reply
https://www.physicsforums.com/threa...ation-of-the-light-clock.1003748/post-6506712