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A comment on Transfer of atomic mass with a photon solves the momentum paradox of light. Parent comment

Re:Transfer of atomic mass with a photon solves the momentum... by henearkr on Sunday July 02, 2017 @11:00AM (#14682760)
I don't see how it is pertinent, as space is not "a transparent medium", it is void. Pretty much all the photons emitted by a star that we can detect cross only the star's gas surrounding, then the emptiness of space, then our atmosphere. So, it does not vary with the distance of the star, thus the author's argument does not hold (anyway, he was being super-speculative here).
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Re:Transfer of atomic mass with a photon solves the momentum... by fpoling on Sunday July 02, 2017 @11:35AM (#14682956)
The space is not void as there is non-zero density of matter that we see in absorbtion lines of quasars [1]. This implies that the space has to be treated as transparent medium with non-trivial optical properties.

[1] - https://ned.ipac.caltech.edu/level5/Madau6/Madau_contents.ht...

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Re:Transfer of atomic mass with a photon solves the momentum... by henearkr on Sunday July 02, 2017 @03:05PM (#14683852)
Ok, now I agree with you: https://ned.ipac.caltech.edu/level5/Madau6/Madau2.html
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Re:Transfer of atomic mass with a photon solves the momentum... by zamalek on Sunday July 02, 2017 @11:08AM (#14682818)
> it is void

Space is not a complete vacuum.

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Re:Transfer of atomic mass with a photon solves the momentum... by henearkr on Sunday July 02, 2017 @03:06PM (#14683854)
Well, actually it seems you are true. There are absorption rays for the inter-galactic medium, as shown in: https://ned.ipac.caltech.edu/level5/Madau6/Madau2.html So, please ignore my previous reply ↓
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Re:Transfer of atomic mass with a photon solves the momentum... by henearkr on Sunday July 02, 2017 @11:10AM (#14682828)
Yeah, but sufficiently so that most photons are not encountering any other things on their way.
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Re:Transfer of atomic mass with a photon solves the momentum... by Nomentatus on Sunday July 02, 2017 @03:15PM (#14683891)
Not clear - have you taken virtual particles into account?
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