Doppler Effect in Accelerating Frames vs Normal Doppler Effect

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Discussion Overview

The discussion centers around the differences in magnitude between the normal Doppler effect and the Doppler effect observed in accelerating frames, particularly in the context of light sources that are accelerating relative to an observer. Participants explore the implications of acceleration on frequency shifts and the relevant formulas involved.

Discussion Character

  • Exploratory
  • Technical explanation
  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • Some participants define the normal Doppler effect as occurring with constant relative speed, while others note that acceleration introduces time-dependent frequency shifts.
  • There is a suggestion that the classical Doppler formula may not apply when dealing with relativistic speeds and accelerating sources.
  • One participant references Einstein's equivalence principle to illustrate how acceleration can affect the perception of light frequency, indicating potential redshift and blueshift effects depending on the observer's position relative to a massive object.

Areas of Agreement / Disagreement

Participants express differing views on the applicability of classical versus relativistic Doppler formulas in accelerating frames, indicating that multiple competing perspectives remain without consensus on the matter.

Contextual Notes

Participants mention the need to consider relativistic effects when discussing light and acceleration, but do not resolve the specific mathematical formulations or assumptions involved in these scenarios.

Hydr0matic
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What is the difference in magnitude between the effects of normal doppler effect and doppler effect in accelerated frames, e.g. when the (light)source is accelerating wrt the observer? What is the formula for doppler effect in accelerating frames?
 
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Hydr0matic said:
What is the difference in magnitude between the effects of normal doppler effect and doppler effect in accelerated frames, e.g. when the (light)source is accelerating wrt the observer? What is the formula for doppler effect in accelerating frames?

What do you mean by normal Doppler effect ?

When velocity of source/observer is not constant, the shift in frequence will be time dependent. It is expressed by the v-formula that depends on time, initial velocity and acceleration.



marlon
 
By normal I mean with constant relative speed.
Since we are dealing with light and spacetime I just assumed that, like in relativity, accelerated frames behave differently.
http://www.du.edu/~jcalvert/phys/doppler.htm
Relativity must be taken into account for the optical Doppler effect, since light, with its velocity of c, is an essentially relativistic object.
Surely, doppler shift from a lightsource with relativistic and extremely accelerating speed isn't governed by the classical doppler formula?
 
Hydr0matic said:
By normal I mean with constant relative speed.

This can be both the "classical" version or the relativistic version of the Doppler effect, depending on how close this velocity is to c.

Surely, doppler shift from a lightsource with relativistic and extremely accelerating speed isn't governed by the classical doppler formula?

Well, in the case of high velocities, the principles of special relativity need to be applied.

marlon
 
To see what effect acceleration has on the frequency/wavelength of light you can invoke Einstein's (gravitational) equivalence principle. Light from a massive object would be seen as red shifted by a distant observer and to an observer closer to the massive object light from a more distance source would be seen as blue shifted.
 

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