Speed of Light Aboard a Spaceship: An Overview

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SUMMARY

The discussion centers on the behavior of light aboard a spaceship traveling at 0.99c, specifically regarding how light's speed is perceived by observers on Earth. It is established that light moves at speed c relative to the ship, and due to the principles of special relativity, velocities do not add linearly. Observers on Earth will measure the light moving towards the front of the ship at speed c and towards the back at speed c, confirming that light's speed remains constant across all frames of reference. The velocity addition formula illustrates that light always travels at c, independent of the ship's speed.

PREREQUISITES
  • Understanding of special relativity principles
  • Familiarity with the velocity addition formula
  • Basic knowledge of the speed of light (c)
  • Introductory physics concepts from Taylor & Wheeler's Spacetime Physics
NEXT STEPS
  • Study the velocity addition formula in detail
  • Read Taylor & Wheeler's Spacetime Physics for foundational concepts
  • Explore Feynman's Lectures on Physics for additional insights into relativity
  • Investigate the implications of time dilation in special relativity
USEFUL FOR

This discussion is beneficial for physics students, educators, and anyone interested in understanding the principles of special relativity and the behavior of light in high-speed scenarios.

TheLil'Turkey
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Let's say a spaceship made of a transparent material moving past the Earth in a straight line at a constant speed of 0.99 c, and it's at its minimum distance from Earth. If a light is turned on in the middle of the ship, for an observer on Earth will the light move towards the front of the ship at the speed c (with a speed of 0.01 c relative to the front of the ship) and towards the back of the ship at the speed c (with a speed of 1.99 c relative to the back of the ship?

If time moves more slowly on the ship for an observer on Earth, shouldn't light move equally slowly in any direction relative to the ship?

I'd like to understand the basics of special relativity; what should I read? The part of Feynman's lectures on physics that deals with this is all that I've read so far.
 
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TheLil'Turkey said:
If a light is turned on in the middle of the ship, for an observer on Earth will the light move towards the front of the ship at the speed c (with a speed of 0.01 c relative to the front of the ship) and towards the back of the ship at the speed c (with a speed of 1.99 c relative to the back of the ship?

Light moves at ##c## relative to the ship. Velocities don't add linearly in relativity; see here:

http://en.wikipedia.org/wiki/Velocity-addition_formula#Special_theory_of_relativity

If you apply this formula when ##v = c##, you will see that it gives ##s = c## regardless of the value of ##u##; so light moves at ##c## relative to all observers.

TheLil'Turkey said:
I'd like to understand the basics of special relativity; what should I read?

Taylor & Wheeler's Spacetime Physics is a good introductory text.
 

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