How would the solar system appear if you approached at near c?

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Discussion Overview

The discussion revolves around the relativistic effects experienced when approaching the solar system at velocities near the speed of light (c). Participants explore concepts from special relativity (SR), including time dilation, length contraction, and the implications for observing Earth's orbit from such a frame of reference. The conversation includes theoretical scenarios and challenges related to the interpretation of these relativistic effects.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested
  • Mathematical reasoning

Main Points Raised

  • Some participants propose that approaching Earth at near-c would result in significant length contraction, suggesting that distances would appear foreshortened to a Planck length.
  • Others argue that time dilation is not directional, asserting that if Earth's clock appears slow, it does not imply that Earth is moving quickly in any direction relative to the sun.
  • There is a contention regarding the interpretation of time passing on Earth versus the traveler's experience, with some suggesting that a century on Earth corresponds to a Planck time for the traveler.
  • Some participants challenge the notion of a theoretical maximum speed, stating that one can always accelerate closer to c, while others emphasize that the maximum speed is not c but rather anything less.
  • One participant questions the use of specific numbers in examples, suggesting that simpler values would facilitate discussion.
  • Another participant notes that the scenario's specifications regarding time and distance must be clearly defined within a specific reference frame to avoid confusion.
  • There are conflicting interpretations about whether Earth's clocks would appear to run faster or slower from the traveler's perspective, leading to further clarification attempts.

Areas of Agreement / Disagreement

Participants express multiple competing views on the effects of relativistic travel on time and distance measurements. The discussion remains unresolved, with no consensus on the implications of approaching the solar system at near-c speeds.

Contextual Notes

Limitations include the need for clear definitions of reference frames when discussing time and distance, as well as the complexities introduced by relativistic effects that may not be fully addressed in the conversation.

  • #121
Raymond Potvin said:
It will increase with redshift when going away, and decrease with blueshift when going back, so at the end, one year will have elapsed for each Earth cycle.

It's true that there's a red shift going away and blue shift returning, It's not true that at the end one year will have elapsed on the traveling twin's clock for every trip Earth made around the sun.
 
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  • #122
Raymond Potvin said:
I see! As I thought, the observer is still looking at the clocks go by, so it is not really a new experiment, moreover, it only injects the result of a mind experiment into another one, which is far from deducing the same result out of two different experiments.

But you can do a complete and independent analysis of the parallel light clock with no reference to the perpendicular one. When you do the math two things stand out:

1. The results of the perpendicular light clock analysis match the results of the parallel light clock analysis.

2. The results of the perpendicular light clock analysis match what we observe real clocks doing.

Thousands of engineers, technicians, and scientists work with time dilation every minute of every day at hundreds of locations across the world. It's real.
 
  • #124
Mister T said:
It's just that the time that elapses for each orbit will be less for the traveler than for someone who remained on Earth.
So, if the traveler's velocity were close enough to c, she might "see" the Earth orbiting the sun millions of times per second?
 
  • #125
Chris Miller said:
So, if the traveler's velocity were close enough to c, she might "see" the Earth orbiting the sun millions of times per second?
If by "see", you mean see with your eyes, using an appropriately powerful telescope then a traveler approaching the solar system could indeed see such a thing.

From the traveler's point of view, the explanation for this would be that the Earth is orbiting the sun quite slowly (time dilation), but that the solar system is approaching the traveler at such a high rate of speed that light from the "Earth last Christmas" has only moved ahead by 1000 feet or so by the time the light from "Earth this Christmas" is being emitted (Doppler effect for a moving emitter).

From the Earth's point of view, part of the explanation for this is that the traveler's clock is slowed down so much that the light from "Earth last Christmas" and "Earth this Christmas" arrive one microsecond tick apart according to the traveler's massively slowed clock (time dilation). The other part is the fact that the traveler is racing ahead to meet all the images of Christmases past so that the rate nearly doubles (Doppler effect for a moving receiver).
 
  • #126
Raymond Potvin said:
you can get out anytime you want.

Done. Thread closed. Please read the PF rules on personal theories; further posts along the lines you have shown here will receive a warning.
 

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