Can Spaceships Travel Faster Than the Speed of Light?

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Discussion Overview

The discussion centers around the question of whether two spaceships traveling at 0.8c in opposite directions relative to Earth can be said to have a relative speed of 1.6c. Participants explore the implications of relativistic velocity addition and the constraints imposed by the speed of light.

Discussion Character

  • Technical explanation
  • Homework-related
  • Debate/contested

Main Points Raised

  • One participant suggests that the relative speed of the two spaceships could be calculated as 0.8c + 0.8c, questioning the implications of the speed of light as a limit.
  • Another participant asserts that the relative speed cannot simply be added due to the principles of relativity, referencing external resources for clarification.
  • A third participant reiterates the initial question while emphasizing the importance of frame of reference in determining relative speed, suggesting that the definition of "difference of speeds" is crucial.
  • One participant notes that the question may be part of a homework assignment.

Areas of Agreement / Disagreement

Participants do not reach a consensus on the calculation of relative speed, with some arguing for the addition of velocities and others emphasizing the constraints of relativity. The discussion remains unresolved.

Contextual Notes

Participants reference the need for a proper understanding of relativistic velocity addition and the implications of different frames of reference, indicating potential limitations in the assumptions made about speed calculations.

multiix
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Two spaceships are traveling relative to Earth (stationary). One spaceship is going to the right at 0.8c the other is going to the left at 0.8c. Could you say their relative speed to one another is .8c+.8c? I'm thinking not since you can't possible go faster then the speed of light, doesn't matter what the frame of reference is.

Please Help me with the Theory behind this
 
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multiix said:
Two spaceships are traveling relative to Earth (stationary). One spaceship is going to the right at 0.8c the other is going to the left at 0.8c. Could you say their relative speed to one another is .8c+.8c? I'm thinking not since you can't possible go faster then the speed of light, doesn't matter what the frame of reference is.

Please Help me with the Theory behind this

That is their relative speed wrt the earth, not the speed of one to another (note that "relative" can be omitted for the last). So, if for relative speed you use the definition of "difference of speeds" (as Einstein did and as I learned it) then it does matter what the frame of reference is. Further, see the links already provided.
 
This appears to be part of a homework assignment.
 

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