An Annotated List Of Thirty-Three ΛCDM Issues

This post summarizes 33 issues with the ΛCDM "Standard Model of Cosmology" all in one place with annotations to sources discussing each of these issues, but in no particular order.

Some of these issues may someday be convincingly refuted. But, others have been identified repeatedly by independent groups of scientists and have been known for a long time without a satisfactory resolution and have grown stronger as better data has become available. Counting ideas is always a slippery matter and there is room to argue that I should have lumped some of these together or that I should have split some of them up into sub-issues. One can also legitimately argue that some of these are apples and oranges because they involved different kinds of issues. But, collectively, they provide a robust challenge to the ΛCDM model's correctness.

* the wrong gravitational lensing around galaxies in clusters 

(see Massimo Meneghetti, et al., "An excess of small-scale gravitational lenses observed in galaxy clusters" 369 (6509) Science 147-1351 (September 11, 2020). DOI: 10.1126/science.aax5164)

* KIDS evidence of less clumpy structure than predicted 

(see the KIDS website).

* the Hubble tension 

(see, e.g., Adam G. Riess, et al., "A Comprehensive Measurement of the Local Value of the Hubble Constant with 1 km/s/Mpc Uncertainty from the Hubble Space Telescope and the SH0ES Team" arXiv:2112.04510 (December 8, 2021)).

* the wrong DM halo shapes in galaxies 

(see, e.g., James S. Bullock, Michael Boylan-Kolchin, "Small-Scale Challenges to the ΛCDM Paradigm" (July 13, 2017, last updated September 2, 2019), Pengfei Li, Federico Lelli, Stacy McGaugh, James Schombert, "A comprehensive catalog of dark matter halo models for SPARC galaxies" (January 28, 2020). arXiv 2001.10538; Zhao-Qiang Shen, Guan-Wen Yuan, Cheng-Zi Jiang, Yue-Lin Sming Tsai, Qiang Yuan, Yi-Zhong Fan, "Exploring dark matter spike distribution around the Galactic centre with stellar orbits" arXiv:2303.09284 (March 16, 2023) (To be submitted to MNRAS), Mariia Khelashvili, Anton Rudakovskyi, Sabine Hossenfelder, “Dark matter profiles of SPARC galaxies: a challenge to fuzzy dark matter” arXiv:2207.14165 (July 28, 2022); Nicolas Loizeau, Glennys R. Farrar, “Galaxy rotation curves disfavor traditional and self-interacting dark matter halos, preferring a disk component or ad-hoc Einasto function” arXiv 2105:00119 (April 30, 2021); Daniel B Thomas, Michael Kopp, Katarina Markovič, "Using large scale structure data and a halo model to constrain Generalised Dark Matter" arXiv:1905.02739 (May 7, 2019 last updated May 4, 2020) https://doi.org/10.1093/mnras/stz2559; Marie Korsaga, et al., “GHASP: an Hα kinematics survey of spiral galaxies – XII. Distribution of luminous and dark matter in spiral and irregular nearby galaxies using Rc-band photometry” (September 17, 2018); Theodorus Maria Nieuwenhuizen “Subjecting dark matter candidates to the cluster test” (October 3, 2017); Lin Wang, Da-Ming Chen, Ran Li “The total density profile of DM halos fitted from strong lensing” (July 31, 2017); James S. Bullock, Michael Boylan-Kolchin, “Small-Scale Challenges to the ΛCDM Paradigm” arXiv 1707.04256 (July 13, 2017, last updated September 2, 2019); Davi C. Rodrigues, Antonino del Popolo, Valerio Marra, Paulo L. C. de Oliveira, "Evidences against cuspy dark matter halos in large galaxies" arXiv:1701.02698 (January 10, 2017, last revised 13 June 13, 2017) (accepted in MINRAS) and P.L. Biermann, H.J. de Vega, N.G. Sanchez, "Highlights and Conclusions of the Chalonge Meudon workshop 2012: warm dark matter galaxy formation in agreement with observations" arXiv:1305.7452 (May 31, 2013 last revised June 26, 2013))

* excessively tight DM-ordinary matter correlations 

(see, e.g., Paolo Salucci, "The distribution of dark matter in galaxies" (November 21, 2018) (60 pages, 28 Figures ~220 refs. Invited review for The Astronomy and Astrophysics Review), Antonino Del Popolo et al., "Correlations between the Dark Matter and Baryonic Properties of CLASH Galaxy Clusters" (August 6, 2018), https://arxiv.org/abs/2008.04052, and Man Ho Chan, "Two mysterious universal dark matter-baryon relations in galaxies and galaxy clusters" arXiv:2212.01018 (December 2, 2022) (Accepted in Physics of the Dark Universe), Xuejian Shen, Thejs Brinckmann, David Rapetti, Mark Vogelsberger, Adam Mantz, Jesús Zavala, Steven W. Allen, "X-ray morphology of cluster-mass haloes in self-interacting dark matter" arXiv:2202.00038 (January 31, 2022, last revised November 1, 2022) (accepted by MNRAS); Aidan Zentner, Siddharth Dandavate, Oren Slone, Mariangela Lisanti, “A Critical Assessment of Solutions to the Galaxy Diversity Problem” arXiv:2202.00012 (January 31, 2022); Lorenzo Posti, S. Michael Fall “Dynamical evidence for a morphology-dependent relation between the stellar and halo masses of galaxies” arXiv:2102.11282 (February 22, 2021) (Accepted for publication in A&A); Camila A. Correa, Joop Schaye, "The dependence of the galaxy stellar-to-halo mass relation on galaxy morphology" arXiv:2010.01186 (October 2, 2020) (accepted for publication in MNRAS); Paolo Salucci, Nicola Turini, Chiara Di Paolo, "Paradigms and Scenarios for the Dark Matter Phenomenon" arXiv:2008.04052 (August 10, 2020); Paolo Salucci and Nicola Turini, “Evidences for Collisional Dark Matter In Galaxies?” (July 4, 2017); and Edo van Uitert, et al., “Halo ellipticity of GAMA galaxy groups from KiDS weak lensing” (October 13, 2016), Zhixing Li, Hong Guo, Yi Mao, “Theoretical Models of the Atomic Hydrogen Content in Dark Matter Halos” arXiv:2207.10414 (July 21, 2022)(distributions of hydrogen in interstellar space are also inconsistent with a dark matter particle that interacts only via gravity)

* the unexpected relationship between DM proportion and galaxy shape 

(see, e.g., David Winters, Alexandre Deur, Xiaochao Zheng, "New Analysis of Dark Matter in Elliptical Galaxies" arXiv:2207.02945 (July 6, 2022) (published at 518 (2) MNRAS 2845-2852 (2023)); arXiv:2010.01186, and arXiv:2004.05905))

* satellite galaxies in the galactic plane 

(see, e.g., Marcel S. Pawlowski, Pavel Kroupa "The Milky Way's Disk of Classical Satellite Galaxies in Light of Gaia DR2" arXiv (November 12, 2019) (Accepted for publication in MNRAS))

* too few satellite galaxies 

(see James S. Bullock, Michael Boylan-Kolchin, "Small-Scale Challenges to the ΛCDM Paradigm" (July 13, 2017, last updated September 2, 2019) arXiv 1707.04256)

* the unexpected relationship between bulge mass and number of satellite galaxies 

(see B. Javanmardi, M. Raouf, H. G. Khosroshahi, S. Tavasoli, O. Müller, A. Molaeinezhad, "The number of dwarf satellites of disk galaxies versus their bulge mass in the standard model of cosmology" (November 21, 2018) (accepted in The Astrophysical Journal); Dark matter can't explain bulge formation in galaxies: Alyson M. Brooks, Charlotte R. Christensen, "Bulge Formation via Mergers in Cosmological Simulations" (12 Nov 2015))

* the wrong predicted halo mass function 

(see https://arxiv.org/abs/1911.00517)

* impossible early galaxies 

(see, e.g., Labbé, I., van Dokkum, P., Nelson, E. et al. "A population of red candidate massive galaxies ~600 Myr after the Big Bang." Nature (February 22, 2023). https://doi.org/10.1038/s41586-023-05786-2 (open access version available at https://arxiv.org/abs/2207.12446) Manoj K. Yennapureddy, Fulvio Melia, "A Cosmological Solution to the Impossibly Early Galaxy Problem" (March 19, 2018) and https://arxiv.org/abs/2002.11129))

* the EDGES 21 cm result 

(see https://www.nature.com/articles/nature25792)

* evidence for an external field effect 

(see https://arxiv.org/abs/2009.11525)

* evidence that the universe is not homogeneous and isotropic 

(see, e.g., arXiv:2009.14826)

* no dark matter galaxies 

(see Isabel M.E. Santos-Santos, et al., "Baryonic clues to the puzzling diversity of dwarf galaxy rotation curves" (November 20, 2019) (submitted to MNRAS) and Maria Luisa Buzzo, Duncan A. Forbes, Jean P. Brodie, Steven R. Janssens, Warrick J. Couch, Aaron J. Romanowsky, Jonah S. Gannon, "The large-scale structure of globular clusters in the NGC 1052 group" arXiv:2303.16375 (March 29, 2023) (Accepted for publication in MNRAS))

* lack of X-ray emissions in low surface brightness galaxies 

(see https://arxiv.org/abs/1906.05867)

* there are too few galaxy clusters 

(see https://arxiv.org/abs/1902.10837)

* it gets globular cluster formation wrong 

(see Peter Creasey, et al., "Globular Clusters Formed within Dark Halos I: present-day abundance, distribution and kinematics" (June 28, 2018) and Scarpa et al., "Globular Clusters as a Test for Gravity in the Weak Acceleration Regime" (2006) https://arxiv.org/abs/astro-ph/0601581)

* it doesn't explain apparent wide binary star discrepancies 

(see Hernandez et al., "Wide binaries as a critical test for Gravity theories" (2012) https://arxiv.org/abs/1205.5767)

* colliding clusters are too common and too fast 

(see, e.g., Jounghun Lee, Eiichiro Komatsu, "Bullet Cluster: A Challenge to LCDM Cosmology" (May 22, 2010) (published in Astrophysical Journal 718 (2010) 60-65 and "A massive blow for ΛCDM - the high redshift, mass, and collision velocity of the interacting galaxy cluster El Gordo contradicts concordance cosmology" Asencio, E. et al., 2021MNRAS.500.5249A); Sandor M. Molnar, Tom Broadhurst. "A Hydrodynamical Solution For The “Twin-Tailed” Colliding Galaxy Cluster “El Gordo”. The Astrophysical Journal, 2015; 800 (1): 37 DOI: 10.1088/0004-637X/800/1/37)

* the cosmic coincidence problem 

(see, e.g., https://arxiv.org/abs/1410.2509)

* dark energy measurement issues 

(see, e.g., Jacques Collins, et al., "Evidence for Anisotropy of cosmic acceleration", 631 Astronomy and Astrophysics L13 (November 20, 2019) DOI: https://doi.org/10.1051/0004-6361/201936373 and Peter A. Milne, Ryan J. Foley, Peter J. Brown, Gautham Narayan. "The Changing Fractions of Type IA Supernova NUV–Optical Subclasses With Redshift: The Astrophysical Journal, 2015; 803 (1): 20 DOI: 10.1088/0004-637X/803/1/20)

* the wrong predicted DM halo size scaling exponent in clusters 

(see Yong Tian, Han Cheng, Stacy S. McGaugh, Chung-Ming Ko, Yun-Hsin Hsu "Mass-Velocity Dispersion Relation in MaNGA Brightest Cluster Galaxies" arXiv:2108.08980 (August 20, 2021) (published in 24 The Astrophysical Journal Letters 917))

* mean separation of void galaxies and KBC void prediction problems 

(see Saeed Tavasoli, "Void Galaxy Distribution: A Challenge for ΛCDM" arXiv:2109.10369 (September 21, 2021) (Accepted in ApJ Letter) DOI: 10.3847/2041-8213/ac1357 and "The KBC void and Hubble tension contradict ΛCDM on a Gpc scale" Haslbauer, M. et al., 2020MNRAS.499.2845H)

* structure growth and other cosmological parameter tensions 

(see, e.g., the paper in the OP and Elcio Abdalla, et al., "Cosmology Intertwined: A Review of the Particle Physics, Astrophysics, and Cosmology Associated with the Cosmological Tensions and Anomalies" arXiv:2203.06142 (March 11, 2022); Nhat-Minh Nguyen, Dragan Huterer, Yuewei Wen, "Evidence for suppression of structure growth in the concordance cosmological model" arXiv:2302.01331 (February 2, 2023))

* inconsistent with Chandrasekhar dynamical friction 

(see https://archive.ph/wEVQ0)

* spiral galaxy thickness is too thin relative the the predicted value in ΛCDM 

(see "The High Fraction of Thin Disk Galaxies Continues to Challenge ΛCDM Cosmology" Haslbauer, M., et al., 2022ApJ...925..183H)

* predicts too low early star formation efficiency 

(see Deng Wang, Yizhou Liu, "JWST high redshift galaxy observations have a strong tension with Planck CMB measurements" arXiv:2301.00347 (January 1, 2023))

* insufficient satellites of satellites 

(see https://arxiv.org/abs/2303.03025)

* evidence that feedback effects needed to fit models to reality are too weak to fill that function 

(see https://arxiv.org/abs/2303.02929 and Lin Wang, Da-Ming Chen, Ran Li, "Baryon effects on the dark matter halos constrained from strong gravitational lensing" arXiv:1706.03324 (June 11, 2017) (accepted in MINRAS).)

* non-detection of DM particles by myriad means shrinking their possible parameter space in a manner that taking all available data collectively rules out many solutions to some of these issues 

(see, e.g., https://arxiv.org/abs/2011.10431, compiling exclusions mostly from the Particle Data Group https://dispatchesfromturtleisland.blogspot.com/2020/10/current-experimental-exclusions-on-bsm.html,

Shyam Balaji, Divya Sachdeva, Filippo Sala, Joseph Silk, "Dark Matter spikes around Sgr A* in γ-rays" arXiv:2303.12107 (March 21, 2023). https://www.nature.com/articles/s41586-018-0739-1,

Dicong Liang, Lijing Shao, "Improved bounds on the bosonic dark matter with pulsars in the Milky Way" arXiv:2303.05107 (March 9, 2023),

https://arxiv.org/abs/2010.07559, https://arxiv.org/pdf/1408.3583.pdf, https://arxiv.org/abs/1501.00907, https://arxiv.org/abs/1709.02304,

https://arxiv.org/abs/1709.02222, https://arxiv.org/abs/1709.01930, https://arxiv.org/abs/1710.01375, https://arxiv.org/abs/1510.01516,

https://arxiv.org/abs/1710.06488, https://arxiv.org/abs/1708.05681,

https://arxiv.org/abs/1708.04630, https://arxiv.org/abs/1707.01632,

https://arxiv.org/abs/1708.04858,

https://arxiv.org/abs/1301.4984,

https://arxiv.org/abs/1612.00457,

https://arxiv.org/abs/1504.01195,

https://arxiv.org/pdf/1305.7452v2.pdf,

Paolo Salucci and Nicola Turini, "Evidences for Collisional Dark Matter In Galaxies?" (July 4, 2017),

Torsten Bringmann, et al., "Strong constraints on self-interacting dark matter with light mediators" (December 2, 2016),

https://arxiv.org/abs/1504.06576,

Alyson Brooks, "Re-Examining Astrophysical Constraints on the Dark Matter Model" (July 28, 2014),

Dark matter distributions have to closely track baryon distributions, even though there is no viable mechanism to do so: Edo van Uitert, et al., "Halo ellipticity of GAMA galaxy groups from KiDS weak lensing" (October 13, 2016),

Simon Birrer, Adam Amara, and Alexandre Refregier, "Lensing substructure quantification in RXJ1131-1231: A 2 keV lower bound on dark matter thermal relict mass" (January 31, 2017),

Lin Wang, Da-Ming Chen, Ran Li "The total density profile of DM halos fitted from strong lensing" (July 31, 2017),

https://arxiv.org/pdf/1704.01832.pdf,

http://iopscience.iop.org/article/10.1088/1742-6596/718/3/032008/pdf)

* it has made few ex ante predictions that have turned out to be true

(see, e.g. https://tritonstation.com/2020/05/05/predictive-power-in-science/)

* gravitational alternatives to DM have made many accurate ex ante predictions and solve some of the other problems 

(see, e.g. A. Deur, "A possible explanation for dark matter and dark energy consistent with the Standard Model of particle physics and General Relativity" (2017), J. W. Moffat and M. H. Zhoolideh Haghighi, "Modified gravity (MOG) can fit the acceleration data for the cluster Abell 1689" (16 Nov 2016), Nils Wittenburg, Pavel Kroupa and Benoit Famaey "The formation of exponential disk galaxies in MOND." (February 5, 2020) Astrophysical Journal, http://arxiv.org/abs/2002.01941, Constantinos Skordis, Tom Złosnik, "A new relativistic theory for Modified Newtonian Dynamics" arXiv (June 30, 2020), Francesco Sylos Labini, et al., "Mass models of the Milky Way and estimation of its mass from the GAIA DR3 data-set" arXiv:2302.01379 (February 2, 2023) (accepted for publication in The Astrophysical Journal)).