Are the formulas that account for aberraion and doppler shift compatible?

Click For Summary

Discussion Overview

The discussion revolves around the compatibility of formulas that account for the aberration of light and the Doppler shift, focusing on the relationships between light propagation directions and wave measurements from different inertial frames. The scope includes theoretical considerations and mathematical reasoning related to these phenomena.

Discussion Character

  • Technical explanation
  • Conceptual clarification
  • Debate/contested
  • Mathematical reasoning

Main Points Raised

  • One participant presents a scenario involving two observers emitting light and seeks to establish a relationship between the directions of light propagation in different frames, highlighting the essential differences between the aberration and Doppler effects.
  • Another participant asserts that the wavevector being a vector implies compatibility between the two effects.
  • A participant elaborates on the Doppler shift, discussing the measurement of periods and wavelengths, and suggests that frequency and wavevector are components of a four-vector, indicating a potential connection to the invariance of wave phase.
  • Another participant reiterates the importance of comparing time intervals of emissions and receptions in different reference frames to understand the Doppler effect, questioning its implications for the non-longitudinal Doppler shift formula.

Areas of Agreement / Disagreement

Participants express differing views on the compatibility of the formulas for aberration and Doppler shift, with some suggesting they are not different due to the vector nature of the wavevector, while others explore the distinctions in measurement contexts. The discussion remains unresolved with multiple competing perspectives.

Contextual Notes

Participants reference the invariance of wave phase and Lorentz transformations, but there are limitations in the assumptions made regarding the frames of reference and the definitions of the effects discussed.

bernhard.rothenstein
Messages
988
Reaction score
1
Presenting the aberration of light effect we consider that two observers at rest in I and I' in the standard configuration equipped with laser guns start to emit light when they are instantly located at the same point in space. The problem is to find out a relationsship between the directions along which the same ray propagates when detected from the two involved frames.
Presenting the Doppler we consider the the same two observers mentioned above. What we haveto compare are the period at which say observer from I emits two successive wave crests (signals) from the same point in space the moving observer receiving them being located at two different points in space
That is an essential difference between the two effects.
Using the invariance of the phase of a plane wave many textbooks derive a formula that acounts for the Doppler and as a byproduct the formula that accounts for the aberration.
How could the two formulas be physically compatible?
Thanks for your answers.
 
Physics news on Phys.org
I think it is not different because the wavevector is a vector.
 
lalbatros said:
I think it is not different because the wavevector is a vector.

Thanks for you answer. I think that in a Doppler shift experiment we measure a period and reckon the frequency and we measure a wavelength and reckon the wave vector probably because frequency and wave vector are components of a four vector.
The stationary observer can measure the proper period at which the source at rest relative to him emits successive wave crests. The moving observer receives the two wave crests being located at two different points in space measuring the proper period of reception.
Starting with the invariance of the phase of a wave we perform the Lorentz transformation of the space coordinates of an event that takes place at a given point in space. Please be my next room physicist accepting to discuss the problem.
I like Baudelaire!
 
lalbatros said:
I think it is not different because the wavevector is a vector.
Thanks for your answer. Consider please the following definition of the Dopper Effect:

The Doppler Effect is concerned with two pair of events: The emission of two successive wave crests by the source and the reception of the corresponding wave crests by the observer. What we have to compare are the two time intervals: The time interval between the emissions of the time between the emissions and the time interval between receptions both measured, in the classical limit, in the same inertial reference frame. In the relativistic limit the mentioned time intervals are measured in the rest frame of the source and in the rest frame of the observer respectively.
Do you consider that it could lead to the accredited formula for the non-longitudinal Doppler shift?
 

Similar threads

  • · Replies 17 ·
Replies
17
Views
4K
  • · Replies 9 ·
Replies
9
Views
3K
  • · Replies 10 ·
Replies
10
Views
1K
  • · Replies 10 ·
Replies
10
Views
2K
  • · Replies 5 ·
Replies
5
Views
3K
  • · Replies 60 ·
3
Replies
60
Views
7K
  • · Replies 5 ·
Replies
5
Views
3K
  • · Replies 21 ·
Replies
21
Views
2K
  • · Replies 7 ·
Replies
7
Views
2K
Replies
5
Views
2K