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Such an explanation for observed redshift apparently comes up again and again, but thus far hasn't held up to experiment... it even had a name: "tired light". h

Such an explanation for observed redshift apparently comes up again and again, but thus far hasn't held up to experiment... it even had a name: "tired light". https://en.wikipedia.org/wiki/Tired_light https://en.wikipedia.org/wiki/Tired_light It'll be interesting to see if this sparks new debate on the subject.

mannykannot 9y ago
'Tired light' appears to be an umbrella term for various disparate theories that are only related in their attempt to provide an alternative explanation for red shift. If this particular hypothesis, which is not explicitly cosmological, is validated in terrestrial experiments, I think its cosmological implications would be unavoidable.
- gus_massa 9y ago
  > is validated in terrestrial experiments They didn't run any experiments. They only have some a theoretical model and simulations in the computer. The main part of the article, that says that the momentum of the light is split in the photon and in the density wave looks good. (It almost looks obvious, but it's not my expertise area https://xkcd.com/793/ https://xkcd.com/793/ .) The relation with the Hubble constant is totally unexpected. It is not in the abstract of the peer review article. (I can't read the full text.) So it's probably only a declaration for the press release. Take it with a grain of salt.
  - sethrin 9y ago
    The article like nearly every physical article has its preprint available on the arxiv. https://arxiv.org/abs/1603.07224 https://arxiv.org/abs/1603.07224 note: "on the arxiv" and not "on arxiv". The name puns on x => greek letter chi.
nothis 9y ago
If it's proven true, though, would that mean the "expanding universe" theory would be disproved as well?
- GolDDranks 9y ago
  Not necessarily. It might be that this effect is real (this was a computational simulation so an experimental verification is needed.) and needs to be accounted when doing cosmology. But it might very well account just a part of the redshift, and the remainder then needs to be accounted by something else, the default explanation being the expanding universe. Edit: A clarification: I'm not an expert.
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sillysaurus3 9y ago
Without an expanding universe, one problem is "How does everything form, given that gravity exists?" No expansion = everything falls together.
- lanna 9y ago
  not if the universe is flat and simply connected (i.e, infinite): https://physics.stackexchange.com/questions/109063/how-come-that-an-infinite-universe-will-collapse-under-gravity https://physics.stackexchange.com/questions/109063/how-come-...

mannykannot 9y ago

'Tired light' appears to be an umbrella term for various disparate theories that are only related in their attempt to provide an alternative explanation for red shift. If this particular hypothesis, which is not explicitly cosmological, is validated in terrestrial experiments, I think its cosmological implications would be unavoidable.

gus_massa 9y ago
> is validated in terrestrial experiments They didn't run any experiments. They only have some a theoretical model and simulations in the computer. The main part of the article, that says that the momentum of the light is split in the photon and in the density wave looks good. (It almost looks obvious, but it's not my expertise area https://xkcd.com/793/ https://xkcd.com/793/ .) The relation with the Hubble constant is totally unexpected. It is not in the abstract of the peer review article. (I can't read the full text.) So it's probably only a declaration for the press release. Take it with a grain of salt.
- sethrin 9y ago
  The article like nearly every physical article has its preprint available on the arxiv. https://arxiv.org/abs/1603.07224 https://arxiv.org/abs/1603.07224 note: "on the arxiv" and not "on arxiv". The name puns on x => greek letter chi.

nothis 9y ago

If it's proven true, though, would that mean the "expanding universe" theory would be disproved as well?

GolDDranks 9y ago
Not necessarily. It might be that this effect is real (this was a computational simulation so an experimental verification is needed.) and needs to be accounted when doing cosmology. But it might very well account just a part of the redshift, and the remainder then needs to be accounted by something else, the default explanation being the expanding universe. Edit: A clarification: I'm not an expert.
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sillysaurus3 9y ago

Without an expanding universe, one problem is "How does everything form, given that gravity exists?" No expansion = everything falls together.

lanna 9y ago
not if the universe is flat and simply connected (i.e, infinite): https://physics.stackexchange.com/questions/109063/how-come-that-an-infinite-universe-will-collapse-under-gravity https://physics.stackexchange.com/questions/109063/how-come-...