Seeing Relativity -- III. Journeying within the Kerr metric toward the negative gravity region

TL;DR

This paper explores unique features of the Kerr metric, especially negative gravity regions, through analytic and visual raytracing, revealing new phenomena related to null geodesics and spacetime structure.

Contribution

It provides detailed analysis and visualization of the Kerr metric's maximal extension, highlighting phenomena not observed in Schwarzschild or Reissner-Nordström metrics.

Findings

Identification of new phenomena in null geodesic structures

Visual characterization of negative gravity regions

Differences between Kerr and other black hole metrics

Abstract

In this paper we study some features of the Kerr metric both from an analytic and a visual point of view by performing accurate raytracing in various situations. We focus on features that are unique to the maximal analytic extension of the Kerr metric as compared to that of the Schwarzschild or even the Reissner-Nordstr\"om one. A large number of new, yet underexplored phenomena appear, especially regarding the structure of bounded null geodesics and the aspect of the negative gravity regions whose visual characteristics are shown both from outside and inside it.