What is the detected frequency of radiation in a rotating frame of reference?

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SUMMARY

The discussion centers on calculating the frequency of radiation detected from a source on a rotating disk, specifically when the source emits radiation at frequency ω in its instantaneous rest frame. The key challenge arises from the non-inertial frames of the source and detector, which are separated by an angle φ. The solution involves utilizing Lorentz transformations to relate the frequencies in different frames, as outlined in section 2.8 of "Gravitation" by Misner, Thorne, and Wheeler. Understanding this problem requires a solid grasp of relativistic kinematics and the effects of rotation on frequency detection.

PREREQUISITES
  • Relativistic kinematics
  • Lorentz transformations
  • Concept of instantaneous rest frames
  • Understanding of rotating reference frames
NEXT STEPS
  • Study Lorentz transformations in detail
  • Explore the effects of rotation on frequency detection
  • Read section 2.8 of "Gravitation" by Misner, Thorne, and Wheeler
  • Investigate applications of relativistic effects in rotating systems
USEFUL FOR

This discussion is beneficial for physicists, students of relativity, and anyone interested in the implications of relativistic effects in rotating frames of reference.

eep
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Hi,
I've run into a relativistic kinematics question that I'm not sure how to approach. The question states:

"A source and a detector are spaced a certain angle [itex]\phi[/itex] apart on the edge of a rotating disk. The source emits radiation at frequency [itex]\omega[/itex] in it's instantaneous rest frame. What frequency is the radiation detected at? Hint: Little information is given because little is needed."

I have no idea how to approach this. Since the detector and source are on a rotating disk, they are not connected by inertial frames. I want to say that their instantaneous rest frames are somhow connected, that is, the relative velocities of the frames are always the same. But where do I even begin? I thought perhaps I could work out where the detector would receive a photon emmited by the source, and maybe do a lorentz boost from the instantaneous rest frame of the source to a frame where both detector appear to be moving on the edge of the disk, then do a boost from that frame to the frame of the detector using the velocity of the detector at the time it would be received, but that seems complicated... what am I missing here?
 
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Can you get hold of the book Gravitation by Misner, Thorne, and Wheeler? The solution to this problem is given in section 2.8 The Centrifuge and the Photon.
 
Thanks - picked the book up today, that thing weighs a ton!
 

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