CMB as thermal radiation of cosmic dust?

[Vaclav Vavrycuk]

Recently, the origin of the cosmic microwave background as a relic radiation of the Big Bang was questioned and an idea of the CMB as thermal radiation of cosmic dust was revived and revisited.
Under this theory, the temperature of the cosmic dust is predicted to be 2.776 K which differs from the observed value of the CMB temperature by less than 2%.

An introductory lecture is available at:
and its pdf version is at: https://www.ig.cas.cz/wp-content/uploads/2019/03/cmb-1.pdf
The paper about this topic is here: https://academic.oup.com/mnras/article/478/1/283/4975800

Can you find any errors or difficulties in this concept which in fact refutes foundations of the Big Bang theory?

 

[jedishrfu]

We are reopening thread after some discussion.

 

[phyzguy]

The Big Bang theory also predicts the anisotropy of the CMB radiation in exquisite detail, as in the attached diagram. In your model, is it just coincidence that Big Bang theory is able to fit this so well?

 

[PeterDonis]

Can you find any errors or difficulties in this concept which in fact refutes foundations of the Big Bang theory?

In your model, there is no reason for the CMB to be black-body radiation with a single temperature. So how does your model account for the fact that the CMB is, to very high precision, black-body radiation with a single temperature?

 

[Dale]

this concept which in fact refutes foundations of the Big Bang theory?

I think this is more than a bit overstating the case.

First, this claim is not made in the published paper. The arguments and data presented are nowhere near strong enough for such a strong claim to pass peer review. Therefore, such an unsupported claim is also not permitted on PF. The standard for PF is that all posts must be consistent with the professional scientific literature, and this claim is not.

Second, there is a vast gulf between providing an alternative explanation and refuting something. In this paper you have, at best, provided an alternative explanation.

Third, the foundations of the Big Bang theory are GR and large scale homogeneity and isotropy. This paper does nothing to refute GR. It seemed to me that you do discard homogeneity at least in the large scale distribution of dust. If I understood that correctly then that is a very ugly assumption, and requires some substantial justification and corroboration. Why are we at the center of this low-dust region? Is there other evidence to corroborate that fact? Again, at most the inhomogeneous dust is an alternative to homogeneity, not a refutation of homogeneity.

Please continue this discussion within the rules of the forum by not making claims that go beyond the claims in the actual published paper.

 

[Vanadium 50]

This paper is disappointing.

It predicts a temperature that is different from the measurement "by 1.9 per cent only", but neglects to point out that 1.9% is more than 80 standard deviations from the measured value. In short, the prediction doesn't match the data. The author blames this on the model inputs, but there is not even a rudimentary error analysis. One might even argue with this on philosophical grounds: data which support the theory are accepted, but data that do not are suspect.

 

[Vaclav Vavrycuk]

In your model, there is no reason for the CMB to be black-body radiation with a single temperature. So how does your model account for the fact that the CMB is, to very high precision, black-body radiation with a single temperature?

I agree, this is a very important argument. Here is my reply:

1. One of the first arguments against the dust theory was that the dust grains would radiate rather a gray-body spectrum than the black-body spectrum, because of a small size of dust grains. This theory assumed that the grains are ellipsoids of some typical size. However, after discussions in several papers (Wright 1987; Henning, Michel & Stognienko 1995; Aguirre 2000), the authors arrived at the conclusion that it is not this case, because of a complex shape of grains and probably also because of a wide distribution of grain sizes. This causes that the ensemble of dust grains becomes and ideal absorber at all wavelengths that implies also an emitter of the black-body spectrum.

2. There is, however, another very important and strong argument against the dust theory. Even though, we assume that the ensemble of differently shaped grains of various sizes radiate as blackbody, we know that the grains emit at different redshifts because of their varying distance from us. So that if grains have a single temperature at different redshifts, we should observe a mix of differently redshifted black-body spectra but not a black-body spectrum with a single temperature. And here is the beautiful and the most exciting point of this theory. If temperature of dust grains increases linearly with redshift, this effect disappears and we observe just a single black-body spectrum. Moreover, the increase of dust temperature with redshift is not an assumption, but it is derived as a necessary consequence of a decreasing the volume of the Universe with redshift.

 

[Vaclav Vavrycuk]

I think this is more than a bit overstating the case.

First, this claim is not made in the published paper. The arguments and data presented are nowhere near strong enough for such a strong claim to pass peer review. Therefore, such an unsupported claim is also not permitted on PF. The standard for PF is that all posts must be consistent with the professional scientific literature, and this claim is not.

Second, there is a vast gulf between providing an alternative explanation and refuting something. In this paper you have, at best, provided an alternative explanation.

Third, the foundations of the Big Bang theory are GR and large scale homogeneity and isotropy. This paper does nothing to refute GR. It seemed to me that you do discard homogeneity at least in the large scale distribution of dust. If I understood that correctly then that is a very ugly assumption, and requires some substantial justification and corroboration. Why are we at the center of this low-dust region? Is there other evidence to corroborate that fact? Again, at most the inhomogeneous dust is an alternative to homogeneity, not a refutation of homogeneity.

Please continue this discussion within the rules of the forum by not making claims that go beyond the claims in the actual published paper.

Yes, I agree, my question is provocative :-)

However, take into account that the CMB is the only direct observation of the Big Bang. Hence, if the CMB is of another origin than a relic radiation, everything related to the Big Bang is questioned.

When I tried to publish my results, I first focused only on the CMB as thermal radiation of cosmic dust and I tried to avoid any comments related to the Big Bang theory. However, reviewers of the paper claimed that this is not possible just to present an alternative theory and not to mention consequences for the mainstream theory. So they urged me to do that, and I had to analyse in the paper some details about other evidences supporting the Big Bang and I show that surprisingly the evidences of Big Bang are not as firm as one would expect.

As regards your note about he General Relativity, please, keep in mind that Big Bang theory and GR are not the same theories. Definitely, the dust theory is consistent and must be consistent with GR. Einstein’s GR has nothing to do with assumptions of large-scale homogeneity and isotropy, primordial singularity and so on. These assumptions are introduced by Friedmann as an application of GR to a very simple model of the Universe.

 

[Dale]

the increase of dust temperature with redshift is not an assumption, but it is derived as a necessary consequence of a decreasing the volume of the Universe with redshift

Which is a hallmark of the Big Bang. Far from refuting the Big Bang your theory assumes it in its own derivation.

take into account that the CMB is the only direct observation of the Big Bang

This is so far from true that it is astounding you would say it.

Temporarily closed for moderation

Edit: as the OP is unwilling to keep his posts consistent with the professional scientific literature (including his own paper) we will leave the thread closed.