Spatial Geometry of the Large-Scale Universe: The Role of Quantum Gravity, Dark Energy and other Unknowns

TL;DR

This paper challenges the traditional flatness problem in cosmology, arguing that the observed near-flatness of the universe does not necessitate inflation and clarifies misconceptions about this issue.

Contribution

It consolidates previous findings showing the flatness problem is not a valid motivation for inflation, clarifying misunderstandings and providing detailed arguments.

Findings

The universe's near-flatness does not constitute a flatness problem.

Inflation is not necessarily supported as a solution to flatness.

Clarification of misconceptions about cosmological flatness.

Abstract

It has been known for some time that the usual inference drawn from the observed near-flatness of the large-scale Universe - namely the existence of a cosmological "flatness problem", which is then taken as a partial, but key motivation for assuming the existence of an ultra-short, inflationary expansion of the very early Universe - is in itself deeply problematic. The present contribution consolidates the earlier results regarding the absence of a cosmological flatness problem of the sort that could potentially be resolved by inflation, by clearing up some common misunderstandings and by presenting some arguments in more detail.