Cosmology since the first Astro/Cosmo Moriond meeting// The emergence of the Big Bang 2.0

Alain Blanchard

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arXiv · 2605.01977

Cosmology since the first Astro/Cosmo Moriond meeting// The emergence of the Big Bang 2.0

Alain Blanchard

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Abstract

This paper presents a necessarily incomplete review of the evolution of cosmology since the first Astro/Cosmo Moriond meeting in 1981. I trace the journey from the classical Big Bang model based on three pillars -- universe expansion, primordial nucleosynthesis, and the cosmic microwave background -- to the modern $\Lambda$CDM paradigm and the discovery of cosmic acceleration. I discuss major observational milestones: the COBE discovery of CMB fluctuations, the CMB measurements of the flat universe, the pivotal discovery of accelerated expansion through Type Ia supernovae and the emergence of precision cosmology with Planck. I review current tensions in cosmological parameters, particularly the Hubble tension and $\s8$ discrepancies, and discuss future prospects from large-scale structure surveys like DESI. The emergence of ``Big Bang 2.0'' reflects the profound paradigm shift from a model based on standard physics to a dynamical cosmos dominated by dark matter and dark energy, the description of which requires a physics that has yet to be developed and validated.

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Alain Blanchard. 2026-05-03. Cosmology since the first Astro/Cosmo Moriond meeting// The emergence of the Big Bang 2.0. https://arxiv.org/abs/2605.01977

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