Time Contraction in Lorentz Transforms?

Click For Summary

Discussion Overview

The discussion revolves around the concept of time contraction and the relativity of simultaneity as described in Einstein's theory of relativity. Participants explore the implications of light behavior on a spaceship traveling at the speed of light, particularly focusing on how time dilation and length contraction affect the perception of simultaneity between two light emitters positioned at the front and rear of the ship.

Discussion Character

  • Exploratory
  • Debate/contested
  • Conceptual clarification

Main Points Raised

  • One participant suggests that if time dilates, then time in the aft part of the ship should contract to account for the light arriving at the rear faster than intended.
  • Another participant counters that clocks on the moving ship will be perceived as running slow by the same factor, implying no differential time contraction occurs.
  • There is a proposition that the light ray hitting the rear wall early should appear to be frozen due to length contraction, reinstating simultaneity temporarily.
  • A later reply asserts that time dilation does not affect the speed of light, which is constant, and questions whether the rear wall accelerating towards the light beam could imply that time should speed up at the back of the spaceship.

Areas of Agreement / Disagreement

Participants express differing views on the effects of time dilation and length contraction on simultaneity and the behavior of light in the context of a spaceship traveling at light speed. There is no consensus reached on these points, and the discussion remains unresolved.

Contextual Notes

Participants reference the constancy of the speed of light and its implications for time and simultaneity, but the discussion lacks clarity on the assumptions regarding the effects of acceleration and reference frames.

cynopolis
Messages
8
Reaction score
0
The question I have is to do with the Relativity of Simultaneity of the type described by Einstein; whereby two light emitters are placed pulsing once every millisecond on board a spaceship traveling at the speed of light. One of these lights faces forward and the other faces aft. If time dilates in order for the laws of physics to remain the same in all reference frames, shouldn't time in the aft part of the ship contract to deal with the fact that the light has arrived at the rear of the ship faster than intended (so to speak)?

Also if the spaceship has undergone a length contraction, while the angle of the light remains constant in space-time, shouldn't the the light ray - that makes contact with the rear wall of the ship early - continue to move in time to account for the disparagement in the spatial dimension, resulting in it appearing to be frozen to the wall?

If you draw this out you will notice that the light will remain on the rear wall until the forward light reaches its destination, reinstating simultaneity, if only for a brief and, admittedly, lopsided time. Your thoughts on this?
 
Physics news on Phys.org
Does anyone follow me?
 
cynopolis said:
The question I have is to do with the Relativity of Simultaneity of the type described by Einstein; whereby two light emitters are placed pulsing once every millisecond on board a spaceship traveling at the speed of light. One of these lights faces forward and the other faces aft. If time dilates in order for the laws of physics to remain the same in all reference frames, shouldn't time in the aft part of the ship contract to deal with the fact that the light has arrived at the rear of the ship faster than intended (so to speak)?
No. Clocks anywhere in the moving ship will be seen as running slow by the same factor.

Also if the spaceship has undergone a length contraction, while the angle of the light remains constant in space-time, shouldn't the the light ray - that makes contact with the rear wall of the ship early - continue to move in time to account for the disparagement in the spatial dimension, resulting in it appearing to be frozen to the wall?
No.

If you draw this out you will notice that the light will remain on the rear wall until the forward light reaches its destination, reinstating simultaneity, if only for a brief and, admittedly, lopsided time. Your thoughts on this?
Not sure what you are talking about.
 
Ok thanks for those answers.

With regard to the first one though. Time dilation doesn't effect the speed of light (which is a constant) and therefore could not effect the amount of time it takes to the aft light to reach the rear wall. As the rear wall is accelerating towards the beam of light, causing that beam to collide sooner, and the speed of light is supposed to dictate order of events doesn't that mean that time should speed up at the back of the space ship? Please explain your answer.
 
Oh no wait, I get it.
 

Similar threads

Replies
4
Views
1K
  • · Replies 24 ·
Replies
24
Views
3K
  • · Replies 13 ·
Replies
13
Views
3K
  • · Replies 17 ·
Replies
17
Views
5K
  • · Replies 12 ·
Replies
12
Views
3K
  • · Replies 15 ·
Replies
15
Views
3K
  • · Replies 51 ·
2
Replies
51
Views
6K
  • · Replies 2 ·
Replies
2
Views
2K
  • · Replies 184 ·
7
Replies
184
Views
24K
  • · Replies 4 ·
Replies
4
Views
2K