Cosmology

Dark matter, dark energy, and model assumptions

The cosmological licensing question

The cosmology branch of the programme asks whether the standard large-scale smoothing assumptions of ΛCDM remain licensed in precisely the regimes where the dark sector is inferred. The issue is not whether ΛCDM has been successful. It has. The diagnostic question is narrower and more demanding: which parts of that success license the extension of the same modelling assumptions to domains where dark matter and dark energy function as reconstructed explanatory components?

Modern cosmology depends on a controlled relation between observation, geometry, averaging, and interpretation. The FLRW framework idealizes the universe as homogeneous and isotropic on large scales. That idealization is powerful, but it is also a condition of description. Applicability Diagnostics asks whether the conditions that make this smoothing legitimate are still secure when the empirical data point toward a universe structured by voids, walls, filaments, clusters, lensing systems, and late-time inhomogeneity.

Diagnostic focus

Connection to backreaction research

This perspective connects directly to backreaction research, to the Buchert-Wiltshire-Räsänen line of work, and to the methodological status of cosmic averaging. If the geometry used to interpret the data already encodes a smoothing assumption, then the licensing of that assumption becomes part of the explanatory burden. The diagnostic does not claim that backreaction solves the problem. It asks whether backreaction, inhomogeneity, and regime-dependence identify an OPEN debt in the standard interpretation.

The public-facing bridge is the German volume Der blinde Fleck der Kosmologie, while the scientific basis is the monograph Two Symptoms, One Failure. Together they present one core idea at different levels: dark matter and dark energy may be less like two independent substances and more like two coupled symptoms of a modelling boundary that has not yet been fully audited.

• Core themes: Dark Matter · Dark Energy · Backreaction · model assumptions.
• Regime-sensitive reading of FLRW, ΛCDM, and cosmic averaging.
• Clear separation between empirical success and unrestricted explanatory scope.

This is why the cosmology page is framed as an applicability audit rather than as a new cosmological model. It does not offer a replacement parameter set, a final backreaction solution, or a denial of precision cosmology. It identifies the point at which the explanatory interpretation depends on whether the background assumptions themselves remain licensed.