Asymptotic silence of generic cosmological singularities

TL;DR

This paper demonstrates that in generic vacuum cosmological models, particle horizons shrink to zero near singularities, indicating asymptotic silence, and shows that spatial derivatives become insignificant, with dynamics governed by an invariant silent boundary.

Contribution

It provides the first detailed analysis of asymptotic silence and the role of the silent boundary in generic cosmological singularities using the Uggla et al. framework.

Findings

Particle horizons shrink to zero along all timelines.

Spatial derivatives become dynamically insignificant near singularities.

An invariant silent boundary governs the asymptotic dynamics.

Abstract

In this letter we investigate the nature of generic cosmological singularities using the framework developed by Uggla et al. We do so by studying the past asymptotic dynamics of general vacuum G2 cosmologies, models that are expected to capture the singular behavior of generic cosmologies with no symmetries at all. In particular, our results indicate that asymptotic silence holds, i.e., that particle horizons along all timelines shrink to zero for generic solutions. Moreover, we provide evidence that spatial derivatives become dynamically insignificant along generic timelines, and that the evolution into the past along such timelines is governed by an asymptotic dynamical system which is associated with an invariant set -- the silent boundary. We also identify an attracting subset on the silent boundary that organizes the oscillatory dynamics of generic timelines in the singular regime. In addition, we discuss the dynamics associated with recurring spike formation.