Fermat’s principle in black-hole spacetimes. (arXiv:2101.06909v1 [gr-qc] CROSS LISTED)

Fermat’s principle in black-hole spacetimes. (arXiv:2101.06909v1 [gr-qc] CROSS LISTED)
<a href="http://arxiv.org/find/gr-qc/1/au:+Hod_S/0/1/0/all/0/1">Shahar Hod</a>

Black-hole spacetimes are known to possess closed light rings. We here
present a remarkably compact theorem which reveals the physically intriguing
fact that these unique null circular geodesics provide the {it fastest} way,
as measured by asymptotic observers, to circle around spinning Kerr black
holes.

Black-hole spacetimes are known to possess closed light rings. We here
present a remarkably compact theorem which reveals the physically intriguing
fact that these unique null circular geodesics provide the {it fastest} way,
as measured by asymptotic observers, to circle around spinning Kerr black
holes.

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