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In this article (and references therein) the author claims that the Cosmic Background Radiation can be explained as black-body radiation originating from the cold bodies filling the interstellar space (which the author refers to as “Oort soup”).

As far as I know, the mainstream point of view is that CMB is an echo of the Big Bang which dates back to the electroweak symmetry breaking,and has cooled down since then due to the expansion of Universe.

This is the first time I learned about the alternative “Oort soup” hypothesis, which, according to the Author, also favors the Dark Matter model made of cosmic dust. I don’t have enough evidence to judge for myself whether it is pseudoscience or a valid alternative explanation of the CMB.

I would like to know what the position of the scientific community is — is the hypothesis considered pseudoscientific, or a valid (though maybe unlikely) alternative? What scientific evidence against the author’s hypothesis do we have?

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    $\begingroup$ That is not an article. It is crackpot nonsense, like just about everything else on that website. $\endgroup$ – David Hammen Nov 16 '18 at 12:47
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    $\begingroup$ I don't want to read all of this, but I note that 1) the author doesn't address the anisotropy of the CMB (because that cannot be explained in his hypothesis, since the Oort Cloud follows the Solar System), 2) the author claims to be affiliated with "Ben Franklin Centre for Theoretical Research", which doesn't exist, 3) the author has no refereed, or even published, papers (not even on viXra), and 4) this writing is not the only conspiracy theory on his website. $\endgroup$ – pela Nov 16 '18 at 13:18
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    $\begingroup$ @Hammen note that I showed appropriate skepticism in my questions, and there are signs of crackpot science. But I believe in judging ideas based on facts, not feelings or affiliations. Thus, simply saying “crackpot nonsense” may be true, but doesn’t answer my question. Cheers! $\endgroup$ – Prof. Legolasov Nov 16 '18 at 21:09
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    $\begingroup$ Why has this question been downvoted? It's a good question, with a good answer by Rob, something that could not be readily be figured out by a non-physicist. $\endgroup$ – pela Nov 17 '18 at 12:19
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    $\begingroup$ @pela it’s called groupthink, don’t worry about it, I’m used to this kind of stuff on stackexchange sites :) $\endgroup$ – Prof. Legolasov Nov 17 '18 at 12:20
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The idea that belts or spheres of dust might be responsible for (some) microwave emission is not crazy. Indeed we know that dust does emit microwaves and indeed the contribution of such dust has to be removed from the CMB signal before it can be interpreted cosmologically.

There is some debate about some of the larger scale anisotropies (particularly the "quadrupole anisotropy" (of about 1 part in $10^5$) might be the result of badly-subtracted emission from within the solar system because the anisotropy is roughly aligned with the ecliptic plane.0

However, the bulk of the article you refer to is nonsense and betrays a basic lack of understanding of physics and a lack of knowledge about the microwave background.

Just to address a couple of things.

  1. The CMB is an almost perfect black body spectrum. A blackbody spectrum is emitted by perfect blackbodies. The thermal emission from dust is not blackbody radiation. Thermal radiation $\neq$ blackbody radiation. To become blackbody radiation the emission has to come from something that is "optically thick" to that radiation - i.e. it should have a surface that we can see. In other words if we had an opaque sphere of dust around us that had somehow come into perfect thermal equilibrium at 2.7K then this would produce something that looked like the CMB. Unfortunately we would then be unable to see anything else beyond that! For a cosmological interpretation that isn't a problem. We cannot see (at any wavelength) "beyond" the CMB at a redshift of $\sim 1100$. It is a fatal problem for any model where the CMB is optically thick emission from a sphere surrounding the solar system, since we wouldn't be able to see anything beyond the solar system!

  2. The CMB is anisotropic. The most obvious anisotropy is the large (0.1%) dipole anisotropy caused by the motion of the solar system with respect to the rest frame of the CMB. Why should the Sun be moving at about 370 km/s with respect to a spherically symmetric Oort cloud (in the direction with Galactic coordinates $l=264$, $b=48$? Even if the Oort cloud were at a distance of 10,000 au, the Sun would travel beyond it in only $\sim 100$ years! If the sphere is supposed to be further away, what is preventing gravity disturbing its almost perfect uniformity and how does it maintain a perfect thermal equilibrium?

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  • $\begingroup$ Thanks for the detailed answer! Could you clarify your second point please? Are you talking about the dipole moment anisotropy, or also about higher multipolar moments (which I believe are evidence for inflation)? If that is only dipole moment, I think the author is suggesting that cosmic dust fills up the entire galaxy and constitutes “dark matter”, while the solar system simply moves through it. Nice observation in point , however. $\endgroup$ – Prof. Legolasov Nov 16 '18 at 21:14
  • $\begingroup$ @SolenodonParadoxus The solar system isn't travelling at 360 km/s with respect to the Galactic centre or dark matter. Higher multipolar moments are due to acoustic waves in the early universe, not inflation. $\endgroup$ – Rob Jeffries Nov 16 '18 at 23:12
  • $\begingroup$ oh I didn’t mean that higher multipole moments are due to inflation, just that their form suggests that in the early universe space like-separated regions were in thermal equilibrium, thus inflation. Could you please amend to your answer the precise information — in which direction and with which velocity is the solar system drifting wrt CMB and dark matter, and are the dipole red/blue shifts in the CMB in agreement? $\endgroup$ – Prof. Legolasov Nov 17 '18 at 5:11
  • $\begingroup$ @solenodonparadoxus Edited. It is features separated by more than 2 degrees that are explained by inflation. Dark matter is irrelevant to this question and hasn't been detected. It is expected that the solar system travels with the orbital speed of the Sun (about 200 km/s) through dark matter on more isotropic or its. $\endgroup$ – Rob Jeffries Nov 17 '18 at 8:06

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