Unraveling the Mystery of Light Speed: 670 Million MPH

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Discussion Overview

The discussion revolves around the constancy of the speed of light, specifically the assertion that it remains at 670 million mph regardless of the relative speed of observers. Participants explore concepts related to relativity, including time dilation and length contraction, as well as the implications of these ideas on measurements of speed.

Discussion Character

  • Exploratory
  • Technical explanation
  • Conceptual clarification

Main Points Raised

  • One participant questions how light can maintain a constant speed of 670 million mph despite an observer moving at 669 million mph.
  • Another participant suggests that understanding this phenomenon requires knowledge of relativity, recommending literature for further reading.
  • A participant summarizes that time and space adjust in such a way that the speed of light remains constant across different reference frames.
  • Another explanation introduces the concepts of length contraction and time dilation, proposing that changes in measurement occur to keep the speed of light constant for the observer.
  • A participant provides the formula for relativistic velocity addition, inviting others to explore its implications.

Areas of Agreement / Disagreement

Participants express various interpretations of how the constancy of light speed is maintained, indicating that multiple competing views remain without a consensus on the explanation.

Contextual Notes

Some participants reference concepts like length contraction and time dilation without fully resolving the underlying assumptions or mathematical implications involved in these phenomena.

Who May Find This Useful

This discussion may be of interest to those exploring the principles of relativity, the nature of light, and the implications of speed measurements in different reference frames.

no idea
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Can someone explain how it is possible that the speed of light is constantly 670 million mph irrelevant of relative speed? how is it that you can be going 669 million mph yet light still accelerates toward you at the same rate??
 
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Yes, by explaining relativity! But not on this forum- it would take much too long. Any library ought to have a good, fairly elementary, introduction to the theory of relativity. If you are interested, it is certainly worth the time to read such a book.
 
The gist of it is that time and space vary in such a way as to make the speed of light always constant.
 
Here's a place to start;

Speed is the amount of time it takes to go a certain distance. Light's speed is always measured to be the same in every experiment, no matter which way the the observer is travelling, or at what speed. So it was concluded that, in order for light's speed to remain 670 Million mph (relative to the observer) even when the observer's speed changes (relative to whatever reference frame the observer is using), either the miles or the hours must change. So, at 669 million mph, you would still measure the speed of light to be 670 million mph, because your miles are shorter (which is called "length contraction), or your hours are longer (which is called "time dilation").

That's where all the wierdness of Relativity comes from.
 
Relativistic velocity addition:
u' = \frac {u+v}{1+\frac{uv}{c^2}}

play around, see what you get.
 

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