Comments on : Frame dragging anomalies for rotating bodies

TL;DR

This paper critiques prior claims of negative frame dragging in rotating spacetime models, clarifying that such effects occur only in specific regions and correcting misconceptions about the phenomena.

Contribution

It refutes previous conclusions about negative frame dragging occurring at all points, showing it is limited to the 'time machine' region and clarifies properties of Bonnor's spacetime.

Findings

Negative frame dragging occurs only in the 'time machine' region.

Bonnor's spacetime has an event horizon at r=0.

Previous claims of universal negative frame dragging are incorrect.

Abstract

It is shown that Collas and Klein (ArXiv : 0811.2471 [gr-qc]) wrongly concluded that "negative frame dragging" phenomenon takes place at all finite $r$ and $z$ coordinate values . We argue that a test particle with zero angular momentum counter-rotates with respect to the source in the "time machine" region only. In addition, Bonnor's spacetime has an event horizon at $r_{H}$ = 0.