The Failures of the Standard Model of Cosmology Require a New Paradigm

Cosmological models that invoke warm or cold dark matter cannot explain observed regularities in the properties of dwarf galaxies, their highly anisotropic spatial distributions, nor the correlation between observed mass discrepancies and acceleration. These problems with the standard model of cosmology have deep implications, in particular in combination with the observation that the data are excellently described by Modified Newtonian Dynamics (MOND). MOND is a classical dynamics theory which explains the mass discrepancies in galactic systems, and in the universe at large, without invoking 'dark' entities. MOND introduces a new universal constant of nature with the dimensions of acceleration, a₀, such that the pre-MONDian dynamics is valid for accelerations a ≫ a₀, and the deep MONDian regime is obtained for a ≪ a₀, where spacetime scale invariance is invoked. Remaining challenges for MOND are (i) explaining fully the observed mass discrepancies in galaxy clusters, and (ii) the development of a relativistic theory of MOND that will satisfactorily account for cosmology. The universal constant a₀ turns out to have an intriguing connection with cosmology: ā₀ ≡ 2πa₀ ≈ cH₀ ≈ c²(Λ/3)^1/2. This may point to a deep connection between cosmology and internal dynamics of local systems.