Resonant scattering of light in a near-black-hole metric

TL;DR

This paper demonstrates that objects with radii just larger than their Schwarzschild radius can mimic black-hole absorption of light through resonant scattering, trapping photons for long durations and appearing black.

Contribution

It reveals that near-black-hole metrics can produce black-hole-like absorption via resonant states, even without a true event horizon.

Findings

Resonant states cause long-lived photon trapping.

The averaged cross-section matches black-hole absorption.

Objects can appear black without forming a true black hole.

Abstract

We show that low-energy photon scattering from a body with radius R slightly larger than its Schwarzschild radius r_s resembles black-hole absorption. This absorption occurs via capture to one of the many long-lived, densely packed resonances that populate the continuum. The lifetimes and density of these meta-stable states tend to infinity in the limit r_s -> R. We determine the energy averaged cross-section for particle capture into these resonances and show that it is equal to the absorption cross-section for a Schwarzschild black hole. Thus, a non-singular static metric may trap photons for arbitrarily long times, making it appear completely `black' before the actual formation of a black hole.