Speed of light during acceleration

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Discussion Overview

The discussion centers on the behavior of light in an accelerating reference frame, particularly within a ship where an observer at the tail perceives the speed of light differently than an observer at the nose. Participants explore concepts related to non-inertial frames, the implications of acceleration on the perception of time and light, and the use of coordinate systems in special relativity.

Discussion Character

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

Main Points Raised

  • Some participants express confusion about why light appears to travel faster than c in an accelerating ship, questioning the implications of acceleration on light's speed.
  • Others argue that in non-inertial frames, light does not have to travel at c, and reference specific coordinate systems like Dolby and Gull radar coordinates where light can be treated differently.
  • There is a suggestion that the term "speed" should be reserved for Lorentz coordinates, with some advocating for the use of coordinate-independent quantities instead.
  • One participant raises the question of what it means for an object to have a single velocity in an accelerating frame, indicating a need for clarity on the nature of acceleration and velocity in such contexts.
  • Another perspective introduced is that light emitted from an accelerating source experiences Doppler shifts, which could be attributed to time dilation effects between different parts of the ship.
  • Some participants note that the observer inside the ship may be misled about the ticking rates of clocks due to their acceleration, while others challenge this notion, emphasizing that all frames are valid and the observer is aware of their acceleration.
  • A later reply discusses Rindler coordinates as a way to describe accelerated frames, highlighting the non-intuitive nature of simultaneity in such contexts.

Areas of Agreement / Disagreement

Participants express multiple competing views regarding the behavior of light in accelerating frames, with no consensus reached on the implications of acceleration on light's speed or the interpretation of observations made by onboard observers.

Contextual Notes

Some discussions involve assumptions about the nature of acceleration and the validity of different coordinate systems, which may not be universally accepted. The complexity of relating non-inertial frames to inertial observations introduces additional layers of interpretation that remain unresolved.

  • #31
JCMateri said:
I no longer think the last part is correct where I said:
I agree. I think you edited your post - it was shorter when I "like"d it. There are no objects following the lines of constant Rindler time, since those are spacelike. In fact, they are not lines except on the 1+1 dimensional drawing - they are 3d planes in a full 3+1 dimensional case, and are a Rindler observer's notion of "all of space, now" (which goes wrong where they cross at the Rindler horizon).
 

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