If one of the dimensions of our solar system contracted ....

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Discussion Overview

The discussion revolves around the implications of dimensional contraction in the solar system, particularly in the context of observers moving at high speeds. Participants explore concepts related to length contraction, frame dependence, and the effects of relativistic physics on measurements and observations.

Discussion Character

  • Exploratory
  • Debate/contested
  • Technical explanation

Main Points Raised

  • One participant questions whether the solar system would operate the same if one of its dimensions contracted by a factor of 10, suggesting that high-speed observers might perceive differences.
  • Another participant asserts that the behavior of the solar system in its rest frame remains unaffected by external observers, although it may appear different to those moving at high speeds.
  • A participant raises the idea that length contraction might be perceived as an illusion for high-speed observers, prompting further discussion on the nature of this effect.
  • It is noted that length contraction is a measurable effect that varies with the observer's frame of reference, and the terminology used to describe it (e.g., "illusion" vs. "real") does not change the underlying physics.
  • One participant argues that squishing an object, such as a head, involves applying forces that would have significant effects, contrasting this with the frame-dependent nature of size measurements.
  • A later post introduces examples of frame variance from before relativity, questioning the nature of "true" measurements and how different observers can perceive varying kinetic energies for the same object.

Areas of Agreement / Disagreement

Participants express differing views on the nature of length contraction, with some suggesting it is an illusion while others argue it is a measurable effect. The discussion remains unresolved, with multiple competing perspectives on the implications of dimensional contraction and frame dependence.

Contextual Notes

Participants reference previous discussions on similar topics, indicating a history of exploration around the concepts of length contraction and frame variance. There are unresolved assumptions regarding the implications of applying forces to objects and how these relate to relativistic effects.

student34
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... by a factor of 10, then would it operate exactly the same way as if it did not contract?

I ask this because there could be an observer at a sufficient speed for which our solar system contracts by a factor of 10. Wouldn't our solar system and its contents have to behave differently for the observer moving at a high speed?

How can my issue be solved?
 
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student34 said:
... by a factor of 10, then would it operate exactly the same way as if it did not contract?

I ask this because there could be an observer at a sufficient speed for which our solar system contracts by a factor of 10. Wouldn't our solar system and its contents have to behave differently for the observer moving at a high speed?

How can my issue be solved?
The behaviour of the Solar System in its rest frame is unaffected by external observers, whatever their state of motion.

It would certainly look difference to an observer moving at relatively high speed.
 
PeroK said:
The behaviour of the Solar System in its rest frame is unaffected by external observers, whatever their state of motion.

It would certainly look difference to an observer moving at relatively high speed.
Then is length contraction only an illusion to an observer at very high speeds?
 
student34 said:
would it operate exactly the same way as if it did not contract?
Yes. That is guaranteed by the general principle of relativity.

student34 said:
Then is length contraction only an illusion to an observer at very high speeds?
"Illusion" is not a scientific term. Length contraction is a measurable effect which is frame variant. You can call it "illusion" because it is frame variant, or you can call it "real" because it is measurable. The choice of description has no bearing on the physics.
 
student34 said:
Then is length contraction only an illusion to an observer at very high speeds?
No. It represents his/her well-defined measurement of lengths. This is one reason that Newtonian gravity needed to be replaced and wasn't compatible with SR. The eternal observer cannot use ##1/r^2##, with ##r## as measured by him/her.
 
Dale said:
Yes. That is guaranteed by the general principle of relativity.

"Illusion" is not a scientific term. Length contraction is a measurable effect which is frame variant. You can call it "illusion" because it is frame variant, or you can call it "real" because it is measurable. The choice of description has no bearing on the physics.
So this seems to mean that someone can squish my head until it resembles the shape of a pancake, and everything will function the same.

How can this be?
 
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student34 said:
So this seems to mean that someone can squish my head until it resembles a pancake, and everything will function the same.
No, it does not mean anything of the sort. Squishing your head requires applying compressive forces to reduce its size, and of course these forces will have noticeable (and unpleasant) effects. None of this has much to do with the fact that the size of your head, like all sizes, is frame-dependent whether we are applying compressive forces to it or not.

There is no reason to post the same question every month in hopes that the answer will change - it won't.

This thread is closed.
 
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This is getting silly. Let's take trivial examples of frame variance from before relativity. These are no different than the few more cases relativity adds:

1) A light bulb may be emitting white light, blue light, or red light per different observers. Which is the 'true' color, and "how can a light way be squeezed by factor of 10 in one frame and still be unchanged in another frame?" (You can substitute sound waves if you think SR is necessary for Doppler; it actually isn't - it just changes the exact formula compared to what was expected before).

2) How can a canon ball have no kinetic energy for one observer and a lot for the other. How can it not be able to destroy a plane comoving with the canon ball?
 

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