Is the speed of light constant

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Discussion Overview

The discussion revolves around the constancy of the speed of light and the implications of time dilation and relativistic effects as described in hypothetical scenarios involving two observers, one stationary and one moving at a significant fraction of the speed of light. Participants explore the complexities of measuring light speed from different frames of reference and the challenges in conceptualizing these relativistic effects without relying heavily on mathematical formulations.

Discussion Character

  • Exploratory
  • Debate/contested
  • Conceptual clarification
  • Mathematical reasoning

Main Points Raised

  • One participant presents a scenario where two observers measure the speed of light under different conditions of time dilation, questioning how both can measure the same speed of light despite differing time rates.
  • Another participant challenges the clarity of the original scenario, particularly regarding the concept of maintaining the same observational point while one observer is moving at high velocity.
  • A different participant offers an alternative scenario involving two observers and mirrors, illustrating how relativistic effects do not alter the measured speed of light for either observer despite their different states of motion.
  • Some participants emphasize the need to consider both time dilation and length contraction when discussing the Lorentz transformation and its implications for measuring light speed.
  • One participant expresses difficulty in understanding abstract concepts without concrete analogies, suggesting that hypothetical scenarios can complicate comprehension.
  • Another participant notes that analogies can be limiting and may hinder proper understanding of relativistic principles.

Areas of Agreement / Disagreement

Participants express varying levels of confusion regarding the original scenario, with some agreeing that it lacks clarity. There is no consensus on the best way to conceptualize the effects of relativity, and multiple competing views on how to approach the problem remain evident throughout the discussion.

Contextual Notes

Participants highlight limitations in the original scenario, such as assumptions about simultaneity and the nature of measurements in different frames of reference. The discussion also reflects a dependence on hypothetical constructs that may not accurately represent physical realities.

Who May Find This Useful

This discussion may be of interest to individuals exploring concepts of relativity, time dilation, and the speed of light, particularly those seeking to understand these ideas through hypothetical scenarios and analogies.

  • #31
John15 said:
The Earth is moving through space at a minimum of 7500kps.
"Moving through space" is a nonsense phrase. The Earth is moving at 0 in its rest frame and at 7500 in some other frame (e.g. the rest frame of the local CMB radiation). There is no "rest frame of space".
 
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  • #32
If the Earth can have a rest frame of 0 whilst moving through space then that must apply to all including wavelengths of energy, everything is governed by the same rules.
Its obviously not the Earth that has the rest frame though its us as the observers having a 0 rest frame relative to the earth, we cannot know however the Earth's relative speed to anything outside the solar system with any accuracy.
I am guessing however that c is acctually a universal frame of reference as it is the only thing that has constant uniform speed to which all other speeds can be related. Its actual speed is therefore unimportant just that its uniform.
 
  • #33
John15 said:
Light obviously reaches the speed of light.
That is not only not "obvious", it is untrue. Light does not "reach" the speed of light is at c from the instant it is created. Light always travels at "c".
(Saying "light always travels at the speed of light" is subject to misinterpretation!)

Question is then what happens to it at this speed that stops it going any faster?
 
  • #34
John15 said:
If the Earth can have a rest frame of 0 whilst moving through space then that must apply to all including wavelengths of energy, everything is governed by the same rules.
Yes, everything is governed by the same rules and those rules say that something traveling at c in one inertial frame is traveling at c in all frames. This implies that it is not traveling at 0 in any inertial frame.
 

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