Why does gravitational radiation produce vorticity?

TL;DR

This paper investigates how gravitational radiation induces vorticity in observers' world-lines within a Bondi--Sachs framework, linking the effect to the super--Poynting vector, analogous to electromagnetic cases.

Contribution

It establishes a theoretical connection between gravitational radiation-induced vorticity and the super--Poynting vector in a general Sachs metric.

Findings

Vorticity of observers' world-lines is produced by gravitational radiation.

The effect is related to the super--Poynting vector, similar to electromagnetic cases.

Provides a theoretical framework for understanding vorticity in radiative spacetimes.

Abstract

We calculate the vorticity of world--lines of observers at rest in a Bondi--Sachs frame, produced by gravitational radiation, in a general Sachs metric. We claim that such an effect is related to the super--Poynting vector, in a similar way as the existence of the electromagnetic Poynting vector is related to the vorticity in stationary electrovacum spacetimes.