Globally Causal Solutions for Gravitational Collapse

TL;DR

This paper argues that the only physically consistent model of gravitational collapse involves nonsingular, continued collapse solutions, challenging traditional singular black hole models and impacting understanding of black hole properties and evolution.

Contribution

It introduces exact solutions supporting nonsingular collapse, showing other solutions are unphysical near horizons, and discusses implications for black hole physics and numerical methods.

Findings

Nonsingular collapse solutions are physically consistent.

Other known solutions are unphysical near horizons.

Interior regions have well-defined volumes and depend on history.

Abstract

Through an illuminating thought experiment we demonstrate that the nonsingular "continued collapse" picture of a black hole is the only consistent and physical one. We provide a class exact solutions on the boundary of the space of physical configurations. This will show that all the other known exact solutions are unphysical near the surface of the event horizon or in the interior. This will have important consequences for the no-hair conjecture and the kinds of persistent fields that can emerge from a black hole as well as the evolution during collisions and near grazing events. The interior of these holes are characterized by a limiting degenerate metric and these regions tend to well defined volumes and radii in contrast with what is inferred from singular solutions. Surprisingly, these depend on past history and not simply the mass or external fields of the body. It is shown that there is often a well defined "hidden" flat background that can be used to equivalently reformulate GR in terms of a classical nonlinear gravity field and gives local conservation laws. This has implications for unification efforts and numerical approaches to handle the degenerate metric regions reminiscent of the Rankine-Hugoniot conditions. Possible consistency problems with current numerical approaches to black hole dynamics are discussed.