Black holes: A physical route to the Kerr metric

TL;DR

This paper explores the potential physical process by which rotating matter configurations could evolve into Kerr black holes, examining the transition from normal matter to black hole states.

Contribution

It introduces the concept of a quasi-stationary transition from rotating matter configurations to Kerr black holes, providing a possible physical pathway for black hole formation.

Findings

The exterior field of rotating stars generally differs from the Kerr metric.

A theoretical framework for a gradual transition to Kerr black holes is proposed.

Implications for black hole formation processes are discussed.

Abstract

As a consequence of Birkhoff's theorem, the exterior gravitational field of a spherically symmetric star or black hole is always given by the Schwarzschild metric. In contrast, the exterior gravitational field of a rotating (axisymmetric) star differs, in general, from the Kerr metric, which describes a stationary, rotating black hole. In this paper, I discuss the possibility of a quasi-stationary transition from rotating equilibrium configurations of normal matter to rotating black holes.