Relativistic Doppler Effect near a Black Hole

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SUMMARY

The discussion centers on the relativistic Doppler effect and gravitational redshift experienced by an observer viewing a shining object rotating near a black hole. It confirms that two types of redshifts occur: gravitational redshift and relativistic Doppler effect redshift. When the object moves towards the observer, a blueshift occurs due to the Doppler effect, while the gravitational redshift remains constant. The conversation concludes that it is possible for the kinematic blueshift to cancel out the gravitational redshift, allowing the observer to perceive the light at its original frequency under specific conditions.

PREREQUISITES
  • Understanding of gravitational redshift
  • Familiarity with the relativistic Doppler effect
  • Knowledge of black hole physics
  • Basic algebra for relativistic calculations
NEXT STEPS
  • Research the mathematical formulation of gravitational redshift
  • Study the principles of the relativistic Doppler effect in detail
  • Explore the physics of objects in circular orbits around black holes
  • Investigate observational techniques for measuring redshift in astrophysics
USEFUL FOR

Astronomers, physicists, and students interested in astrophysics, particularly those studying the effects of gravity and motion near black holes.

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TL;DR
Relativistic Doppler Effect near a blackhole
Hey everyone, if I were to view a shining person rotating near a black hole at near the speed of light there would be 2 kinds of redshifts: gravitational redshift and relativistic doppler effect redshift. Right?

But, say at some point, the person is traveling towards me, then the doppler effect would result in a blueshift while the gravitational redshift would remain. Is it possible that if the doppler effect blueshift and the gravitational redshift were equal, would I view the light shining at its original frequency?
 
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Yes.
 
You can always adjust your speed relative to a nearby hovering observer so that your kinematic blueshift cancels the gravitational redshift, yes. It'll happen naturally at some point for an object in a circular orbit (and probably any other), if my algebra is correct.
 

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