http://arxiv.org/abs/2101.06909
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.
S. Hod
Wed, 20 Jan 21
42/61
Comments: 5 pages. This essay received an Honorable Mention in the 2018 Essay Competition of the Gravity Research Foundation