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Cosmological redshift, another thought experiment


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This thought experiment attempts to show how cosmological redshift is NOT a Doppler effect.

Let's imagine that the universe expansion, for some dynamic reasons such as strange behavior of dark energy etc., is highly non-uniform, i.e. it stops and goes. Just for the purposes of this thought experiment. At the time when the universe is not expanding, some far away galaxy emits light. While the light is in transit, the universe expands for some time and then stops again. At the time we observe the light, the universe is not expanding.

The source and the receiver do not move relative to each other at the time of emission nor at the time of reception. Thus, there is no Doppler effect. Will we observe the light redshifted?

(My answer: Yes.) 

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1 hour ago, Genady said:

This thought experiment attempts to show how cosmological redshift is NOT a Doppler effect.

I didn't think the current understanding of the cosmic redshift was due to the doppler effect.

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13 minutes ago, Genady said:

Certainly not.

Then why did you write, "This thought experiment attempts to show how cosmological redshift is NOT a Doppler effect", if we already know it is not a doppler effect?

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1 hour ago, Bufofrog said:

Then why did you write, "This thought experiment attempts to show how cosmological redshift is NOT a Doppler effect", if we already know it is not a doppler effect?

To show in the sense of to demonstrate, not in the sense of to prove.

Edited by Genady
minor grammar correction
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