(by Pavel Kroupa, Friday 21st January 2022)
We humans are, as any living creature, and by necessity, conservative beings. We need to be, since typically most of us prefer to sustain their comfortable arrangements. The cave person will prefer to stay near their cave if the nearby plains below are full of fodder, and they would kill off threats. The cosmologist prefers to stay with their dark matter that made them big and important. So when a comet/climate crisis is discovered to approach Earth and is calculated, with some margin or uncertainty, that it will extinguish known life, it can be easier for the majority to just ignore this and to trust in everything turning out all right in the end. Keep the high spirits up, don’t worry and keep smiling and do not frown, do not spoil the mood by doomsday blubber, don’t look up to the threat. So let us ignore that the temperature of the oceans has already increased by nearly 2 degrees centigrade and that another increase by three will kill off most plankton as shown by Sekerci & Petrovskii (2018) with Earth’s atmosphere consequently running out of oxygen.
What has this to do with modern cosmology? I would claim: everything. The modern, successful homo cosmologicus vehemently defends their dark matter against all odds, even if it means killing the scientific method (testing and falsification of hypotheses using reproducible logical methods); they resist change to their habitat as long as the vast landscape of rewards, awards, grants and riches remains abundant.
On Friday, January 14th, 2022, I watched the Golden Webinar on the Hubble Tension, and on this same Friday there appeared on the arXiv an Annual Review on cosmology. Both scientists (speaker and author) are from the highbrow Kavli Institute for Cosmological Physics at the University of Chicago, and both contributions I found to be remarkable.
In the Golden Webinar on “Tension in the Hubble Constant – Does it mean new Physics?“, the speaker very nicely explained the measurements of the Hubble constant using different distance ladders and which role the uncertainties play. Three points struck me: (1) The speaker declared that the physical reason for the Hubble Tension remains unknown. (2) The speaker declared there to be no other known major tension between observations and the Standard Model of Cosmology (the SMoC, or LCDM model). (3) During the panel discussion, a long time was spent on Penrose’s Conformal Cyclic Cosmology hypothesis and it was speculated that fading dark matter might account for the Hubble Tension. The panel largely agreed that no one knew what dark matter was – it might have a large number of degrees of freedom, thus allowing the introduction of an arbitrary number of free parameters to fit almost anything.
Concerning the three points above, I wrote into the chat two questions (see Figure 1 below). Essentially, accepting the well-observed Gpc-scale KBC void as being a real structure of the Universe, the Hubble Tension must then arise from it logically (Haslbauer et al. 2020). This is because galaxies are accelerated gravitationally towards the sides of the void, and an observer within the void (as we are) then measures an apparent faster expansion of the local Universe (see figure 2 in 52. Solving both crisis in cosmology: the KBC-void and the Hubble-Tension). The Hubble Tension therefore has a very simple physical explanation.
In fact, a real Hubble Tension does not exist: it is merely an apparent effect caused by the observed KBC void (Haslbauer et al. 2020), and it would have been predicted if Wong, Suyu et al. (2020) and Riess et al. (2021) had not made their observations of expansion. It is the same reason, in essence, why apples fall to the Earth: replace the galaxies by apples, and they will fall to where they are attracted to, which is the side of the underdensity.
It was a wonderfull event and fascinating to see how the panel very happily discussed the entirely speculative fading dark matter concept in the context of the Hubble Tension, but no-one appeared to dare to raise the possibility that it might simply be due to the observed KBC void, as in fact it must be. I tried to help the panel by posting my question into the chat, but it appeared to me that, in the intimidating presence of highbrow scientists, discussing fading dark matter was acceptable, while raising the obvious solution was no-go. After all, who wants to ask a seemingly silly down-to-Earth question (“can the observed Gpc underdensity be responsible for the apparent Hubble Tension?”) in view of such intellectual Mt. Everests.
The second point above by the speaker I also found impressive, given that other independent falsifications of the LCDM model at more than five sigma confidence have been published, see the list A-F below. It seems that these contributions were missed in Chicago, or that Chicago Cosmologists “do not look up”. I guess they do not need to look up, since they are already on Mt. Everest.
I am still trying to digest this, which is why I wrote the above first paragraph.
Why was neither the Golden Webinar speaker nor the panel willing to delve into the true physical reason for the Hubble Tension? I think that the problem is that the KBC void, which causes the Hubble Tension, falsifies the SMoC with more than 5sigma confidence (Haslbauer et al. 2020), because the SMoC cannot grow such large and deep under densities within a Hubble time. And furthermore, the Chicago Cosmologists, as represented by the speaker and author (next), seem adamantly to refuse to discuss MOND seriously. But MOND is the only known modern non-relativistic theory of gravitation in which the Universe can grow such a large observed void and observed early very massive interacting galaxy clusters (Asencio et al. 2021). We covered this galaxy-cluster problem on a previous occasion. In MOND, there is no Hubble tension (since the voids form naturally) and very massive interacting galaxy clusters also form naturally in the earlier Universe.
On the same day as the above Webinar, an Annual Review on “The Road to Precision Cosmology” was published on the arXiv: It is to appear in Ann.Rev.Nucl.Part.Sci. 72:1-33, https://arxiv.org/abs/2201.04741v1 .
I was interested, since the author is viewed by many to be an outstanding cosmologist, and I expected a fair, balanced and up-to-date review of cosmology for the community of Nuclear and Particle Physicists. This is an important review: Annual Reviews are corner stones of literature. Often they are the first entry point into a research field. Their role is thus truly important. On contemplating the review, I decided to write the following letter – let it speak for itself:
Letter sent on 17th of January 2022 to those addressed (with minute modifications for this forum):
(CC to Editors, Committee Members and Staff of the Annual Review of Nuclear and Particle Physics, and researchers working on MOND),
Concerning your review article "The Road to Precision Cosmology" which is to appear in Ann.Rev.Nucl.Part.Sci. 72:1-33, https://arxiv.org/abs/2201.04741v1 :
I kindly ask you to adjust this article to represent the modern state of affairs truthfully: As it stands, the article is not a review but a biased misrepresentation of the state-of-the art in the research field. It misrepresents the entire field of cosmology to the research community in Nuclear and Particle Physics.
If not-citing highly relevant research literature is considered to be equivalent to plagiarism, then you have provided a major example of such ill conduct: "Papers published in A&A should cite previously published papers that are directly relevant to the results being presented. Improper attribution — i.e., the deliberate refusal to cite prior, corroborating, or contradicting results — represents an ethical breach comparable to plagiarism." (citing from "Ethical issues: the A&A policy concerning plagiarism and improper attribution: https://www.aanda.org/index.php?option=com_content&view=article&id=136#Ethical_issues ).
In your article, we read "Sec. 3.1.2. False starts. In 1983, Milgrom noticed...."
This is an unacceptable representation of an entire highly successful and vibrant research field in which an increasing number of brilliant young physicists are active in. You claim in this section that MOND cannot be falsified. This is wrong. We are actively working on falsifying this theory. MOND can be falsified by, for example, finding systems that do not obey the non-linear MOND Poisson equation.
our article is not aware of or purposefully ignores that
The LCDM standard model of cosmology is in tension with the data on many different scales with significantly more than 5 sigma confidence.
The data which are in tension with LCDM are at the same time naturally (i.e. without adjustment of any parameter) explained in a cosmological model which is based on Milgromian gravitation (MOND) without cold or warm dark matter.
Some of the relevant very recent major peer-reviewed research contributions (ignored by your article) on this are:
A) The existence of LCDM dark matter particles is in more than 5sigma tension with observed bar pattern speeds through the test based on Chandrasekhar dynamical friction published in 2021: Fast galaxy bars continue to challenge standard cosmology.
B) Very massive galaxy clusters form and interact at high redshift being in more than 5sigma tension with LCDM published in 2021: A massive blow for ΛCDM - the high redshift, mass, and collision velocity of the interacting galaxy cluster El Gordo contradicts concordance cosmology.
C) The observed local Gpc scale underdensity causes the Hubble tension and is in more than 5sigma tension with LCDM published in 2020: The KBC void and Hubble tension contradict ΛCDM on a Gpc scale - Milgromian dynamics as a possible solution,
Apart from the above extreme inconsistencies of the LCDM model with the respective data (spanning kpc to Gpc scales), MOND accounts for these naturally and it also naturally accounts for:
D) A planar group of galaxies recedes too rapidly from the Local Group (in >3.96 sigma tension with LCDM) published in 2021: On the absence of backsplash analogues to NGC 3109 in the ΛCDM framework.
F) The planar (disk-like) distribution of satellite galaxies is inconsistent with LCDM but arises naturally in MOND published in 2018: MOND simulation suggests an origin for some peculiarities in the Local Group and Origin of the Local Group satellite planes.
Your article neither cites nor discusses these, and falsely implies the LCDM model to be consistent with the data at the precision level. Further, the review appears to suggest there to be no other model (without dark matter) that can claim comparable success. Claiming today that the LCDM model is a "triumph of precision cosmology" (Sec. 4.1 in your article) is purposefully propagating outdated misinterpretations to an audience who are non-experts in this research field.
I will publish the contents of this email as an open letter, and I hope to receive a constructive reaction.
(Helmholtz-Institut for Nuclear and Radiation Physics, Bonn; Astronomy Institute, Charles University, Prague)
The interested reader might also consult “It’s time for some plane speaking” published by Marcel Pawlowski (2021) in Nature Astronomy. Although Marcel suggests there to be no obvious solution in sight, in MOND, the solution is quite trivial. The planes of satellites come from galaxy-galaxy encounters, as explicitly demonstrated by Bilek et al. (2018, A&A and 2021, Galaxies) and Banik et al. (2018, MNRAS).
In The Dark Matter Crisis by Moritz Haslbauer, Marcel Pawlowski and Pavel Kroupa. A listing of contents of all contributions is available here.