# Relativistic parallel rods

Discussion in 'Physics & Math' started by Pete, Apr 30, 2013.

1. ### brucepValued Senior Member

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Exactly. For instance the HST remotely recording events far away in space and time. Just to say one last thing. I'll use the HST for further example. The HST represents a remote coordinate frame when we choose and a local proper frame when we choose.

3. ### Neddy BateValued Senior Member

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And yet, in the OP of this thread, there are boxes which pass very closely by each other. So they are not far away in space or time when they pass by. Yet the effects of special relativity are still there, as plain as day.

5. ### brucepValued Senior Member

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4,098
You saying it's not a remote coordinate measurement just because they pass close to each other? There's a local proper frame where the two boxes are at rest with respect to each other and they're any number of remote coordinate frames where the boxes are in relative motion with the measurements made in the local proper frame. You haven't understood a thing I've said about how the theory works. You probably think I don't understand what I'm talking about. You wouldn't be the first.

7. ### Neddy BateValued Senior Member

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No, I'm saying that you tried to explain your "remote coordinate frame" in terms of it being a great distance away from the "local proper frame". Maybe you should have explained it in terms of its relative motion, if you were trying to explain SR.

No, there isn't. The boxes are not at rest with respect to each other. Maybe you should review the first post of this thread.

I'm sure you understand what you are talking about. I'm not sure others understand what you think you are talking about.

8. ### brucepValued Senior Member

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4,098
Have it your way. I'm very explicit in my explanations. I could care less whether you understand them or not. The reason you can't understand me is you don't have the will or the tools to tell whether I'm full of crap or not. Later.

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

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Now you're confusing me. You obviously care if he understands them, because if you didn't you would be caring less, but you don't, right?

10. ### TrooperSecular SanityValued Senior Member

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Pete, were you guys just arguing about whether or not the observed angles are transformed during changes of frames of reference?

Relativistic Transformation of Angles

11. ### OnlyMeValued Senior Member

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The thread has jumped back and forth from the OP to the subject of other threads and side tracks so much... But that is not what I understood Pete's OP to be about.

The link you referenced seems to me consistent with the OP.

The word observed may raise Tach's hackles, and the OP was looking at diagonal rods in relativistically moving boxes, rather than specifically at angles, but that is just a different way of looking at the same issue.

I am unsure how Tach's reference to zero angles addresses the OP.

12. ### PeteIt's not rocket surgeryRegistered Senior Member

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We were, but Tach now agrees that the animations at the start of this thread are valid.

13. ### TachBannedBanned

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...albeit totally useless in solving the problem that spawns now four threads.

14. ### RJBeeryNatural PhilosopherValued Senior Member

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Hope...
...dashed.

To imply that the solution can only be resolved in GR even when it can be completely isolated to (and explained with) SR phenomena is absurd.

15. ### PeteIt's not rocket surgeryRegistered Senior Member

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I find it puzzling that Tach acknowledges that two rods can pass each other as shown, but can't seem to accept that they could collide. Unless he's changed his mind about that as well.

16. ### TachBannedBanned

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When they collide they move as a single body or they bounce off each other. Either way, they don't move the way you have them in your animation, your animation does not cover collision, remember? So , this whole thread has nothing to do with the puzzle to be solved, it is just another diversion.
When do you plan to unlock the other thread, the one that explains away your misconceptions about this experiment? How much longer do you plan to keep it locked? Until people forget about the fact that RoS is not measurable through any experiment?

17. ### arfa branecall me arfValued Senior Member

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5,632
Someone might be able to point out what a rigid body means in the context of SR. For instance, how are the point of intersection and the angle of intersection related when the rods aren't parallel (for whatever reason)? When the rods are parallel there is no intersection angle, and no point of intersection (so what)?

In the context of SR, although 'rigid' measuring rods exist, rigid bodies don't (because length contraction is real). When the rods aren't parallel, the point of intersection changes faster than the apparent velocity of the 'moving' rod. So a large velocity for one of the rods means the point of intersection's velocity along the stationary rod can be > c, a contradiction.

Last edited: May 19, 2013