Atomic Oscillations & Redshift in Sun and Earth

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Discussion Overview

The discussion revolves around the phenomenon of redshift as it relates to atomic oscillations in the Sun and the detection of photons by an observer on Earth. Participants explore the implications of gravitational redshift and whether it can be attributed to the emission point or the journey of the photon, as well as the potential effects of the Sun's rotation and thermal motion.

Discussion Character

  • Debate/contested

Main Points Raised

  • One participant questions whether photons emitted from atoms in the Sun experience redshift due to differences in atomic oscillations or due to gravitational effects as they travel to Earth.
  • Another participant asserts that gravitational redshift can be assigned to either the emission point or the travel path, suggesting that both perspectives yield the same predictions for measurements.
  • Some participants mention additional factors such as redshift and blueshift related to the Sun's rotation and thermal motion, although they indicate these may not be central to the original question.
  • A later reply suggests that only one type of shift should be expected, implying that the two perspectives on redshift may be equivalent rather than additive.
  • One participant agrees with the idea of not double-counting the effects, indicating a preference for a singular interpretation of redshift.

Areas of Agreement / Disagreement

Participants express differing views on whether the redshift should be considered as arising from one or two distinct effects, indicating that the discussion remains unresolved.

Contextual Notes

Participants reference specific literature on gravitational redshift, but the discussion does not resolve the assumptions or definitions that underlie the differing interpretations of redshift.

Mickey1
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My question is very simple (and I assume it has been discussed before but I cant't find the topic):

An atom in the Sun emits a photon detected by an observer on Earth. Disregarding uncertainties and experimental problems relating to the movement of the atom (or assuming we could correct for it)

1 Should one expect:

differences in the oscillations of atoms in the Sun - from our observation point - so that a photon would leave the atom with a redshift – and then acquire additional redshift though its journey out of the Sun’s gravity field (also taking the lower gravity field of the observation point into account).

2 Alternative should we only expect:

one of these effects, perhaps being the same effect explained in two different ways?

The problem is also mentioned in K. Wilhelm, B. N. Dwivedi, On the gravitational redshift, Aug. 2014, Pages 8–13, accessed in arXiv:1307.0274.
 
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There is gravitational redshift. You can assign this to the point of production or the journey on the way to us - it doesn't make a difference. Both views, when treated consistently, lead to the same predictions for all measurements.

There is redshift and blueshift associated to the rotation of the Sun, you also have some thermal motion, but I guess these effects are not what the question is about.
 
mfb said:
There is gravitational redshift. You can assign this to the point of production or the journey on the way to us - it doesn't make a difference. Both views, when treated consistently, lead to the same predictions for all measurements.

There is redshift and blueshift associated to the rotation of the Sun, you also have some thermal motion, but I guess these effects are not what the question is about.

I take it then we should only expect one shift, i.e. any of the two, which you consider equivalent, and not two on top of each other.
 
You shouldn’t double-count, sure.
 

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