Wednesday, January 5, 2022

Gravitational Alternatives To Dark Matter Predict Early Galaxies

The James Webb Space Telescope which was successfully launched on Christmas Day 2021 is optimized for observing the near infrared and mid-infrared range of light, which should capture light from galaxies and galaxy clusters from about 13 billion years ago.  

The LambdaCDM Standard Model of Cosmology predicts quite late formation of galaxies and galaxy clusters as demonstrated, for example, by De Lucia & Blaizot (2007). But MOND-based theories and the gravitational self-interaction based approach of Alexander Deur, predict much earlier galaxy formation.

Less impressive telescopes suggest that galaxies were starting to form very early on. This is called the "Impossible Early Galaxy Problem", first described in those terms in Steinhardt et al. (2016), and confirmed in Franck (2017). But the JWST will make that evidence much more clear one way or the other.

The Impossible Early Galaxy Problem is a major blow to the LambdaCDM model, because it starkly contradicts this model not only at the "small scale" level of individual galaxies, but at the "large scale structure" scale of cosmology as a whole. (Another major cosmology scale challenge is the 21cm absorption signal observed by EDGES at cosmic dawn, which is consistent with no dark matter.)

A new post at Triton Station by Stacy McGaugh examines this from a MOND perspective, citing, for example, Sanders (1998)Sanders 2001, and Skordis & Złośnik (2021) (among other things, reproducing the cosmic microwave background power spectrum often touted as the crowning accomplishment of the LambdaCDM model). Alexandre Deur also has a 2021 article on point:

We check whether General Relativity's field self-interaction alleviates the need for dark matter to explain the universe's large structure formation. We found that self-interaction accelerates sufficiently the growth of structures so that they can reach their presently observed density. No free parameters, dark components or modifications of the known laws of nature were required. This result adds to the other natural explanations provided by the same approach to the, inter alia, flat rotation curves of galaxies, supernovae observations suggestive of dark energy, and dynamics of galaxy clusters, thereby reinforcing its credibility as an alternative to the dark universe model.
Alexandre Deur, "Effect of gravitational field self-interaction on large structure formation" arXiv: 2018:04649 (July 9, 2021) (Accepted for publication in Phys. Lett. B) DOI: 10.1016/j.physletb.2021.136510.

Other gravitational based alternatives to dark matter (such as John W. Moffat's MOG theory) also appear, generically, to lead to earlier galaxy formation than cold dark matter theories do. See, e.g., J.W. Moffat (2015). MOG also explains the cosmic microwave background power spectrum. J.W. Moffat (2001).

Both Deur and Moffat's works also overcome the galactic cluster scale difficulties that are an impediment to MOND.

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