Faster than 'c' measurements that do not violate relativity theory

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SUMMARY

The discussion centers on the phenomenon of gas jets from galaxies appearing to travel faster than the speed of light, 'c', without violating relativity theory. The key explanation involves the concept of the index of refraction, where the speed of light can exceed 'c' in media with an index of refraction less than one. This understanding clarifies that the jets are not traveling in a vacuum, thus adhering to the principles of relativity. The equation v=c/n is crucial, indicating that the velocity of light in a medium depends on its refractive index.

PREREQUISITES
  • Understanding of relativity theory and the constant 'c'
  • Familiarity with the concept of the index of refraction
  • Basic knowledge of astrophysics, particularly regarding galaxies and their jets
  • Ability to interpret qualitative responses in physics
NEXT STEPS
  • Research the implications of the index of refraction on light speed in various media
  • Explore advanced concepts in relativity theory and its exceptions
  • Study the behavior of astrophysical jets and their properties
  • Learn about the implications of faster-than-light phenomena in theoretical physics
USEFUL FOR

Astronomy students, physicists, and anyone interested in the principles of relativity and astrophysical phenomena involving light and speed.

FinestHour86
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Homework Statement



Some collections of stars called galaxies release jets of gas. Some of these jets have been measured to travel faster than the speed of light in a vacuum. Explain why relativity theory is not violated.

Homework Equations



This problem requires a qualitative response and no equations are required to answer it.

The Attempt at a Solution



Since according to relativity theory 'c' is a constant, I do not see how it is possible to answer this question. Seemingly this phenomenon does violate relativity theory.
 
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Though I know almost nothing about astro, I'll bet the answer has to do with the jets not actually traveling in a vacuum, and with an index of refraction that changes the speed of light in the index to be faster than the speed of light in a vacuum. That should get you started until an astro person comes along.

v=c/n

so you need n<1
 

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