The Averagely Radial Speed of Light for The Rotating And Charged Black Hole

TL;DR

This paper investigates the average radial speed of light near Kerr-Newman black holes, suggesting it can exceed c close to the black hole due to gravitational effects, but approaches c at large distances, with implications for gravity propagation.

Contribution

It introduces a calculation of the average radial speed of light around rotating charged black holes and offers a new explanation for superluminal observations near such objects.

Findings

Average radial light speed can exceed c near black holes.

Light speed approaches c at large distances from the black hole.

Observation of superluminal particles may be due to light bending effects.

Abstract

The Kerr-Newman metric is used to discuss the averagely measured speed of light along the radial direction at the black hole from a weak-gravitation reference frame such as an observer on Earth. The velocity equation of light at the black hole is represented in the spherical coordinate (r, thita, phi) and the main parameters are the Schwarzschild radius RS, the rotation term a, and the charged term RQ. From the calculations, the averagely radial speed of light from r=Rs to r= (alpha)Rs with alpha>1 is possibly exceeding the speed of light c in free space by an observer in a reference frame far away from the black hole like on Earth. The result extends to the large r region when the rotation of the black hole is very high or the charge is large enough. This averagely radial speed finally goes to c in a large distance away from the black hole. We also propose a new explanation based on our results that the observation of the faster-than-light particle is due to the light bending near the black hole or supermassive star with very strong gravity. Finally, we also give explanation that the propagation speed of gravity shall not be faster than the corresponding speed of light.