Cosmologists and their metaphors: Follicly-Challenged Stars

People who theorize about the physics of the cosmos looooove, some of them, to come up with metaphors that extend the metaphors that other cosmologists came up with. This new paper shows how that’s done:

Physiciist Simon Morris, who noticed the subtle extension of tthe lack-of-hair-metaphor
Physicist Simon Morris, who noticed the subtle extension of the lack-of-hair metaphor

Relating Follicly-Challenged Compact Stars to Bald Black Holes,” Kent Yagi and Nicolas Yunes, arXiv:1502.04131, February 13, 2015. (Thanks to Simon Morris [pictured here] for bringing this to our attention.) The authors, at Montana State University, explain:

“Astrophysical black holes are said to have no hair because their exterior gravitational field can be completely described by only two observable quantities: their mass and their spin angular momentum. All other information or hair that may have led to the formation of the black hole is hidden inside its event horizon…. The nonapplicability of the no-hair theorem extends, in principle, to all stars, including compact ones, such as neutron stars and strange quark stars. There is therefore no reason to expect stars to be bald, i.e. for their exterior gravitational field to be independent of their internal structure…. [The] inter-relations between multipole moments correspond to compact star no-hair relations if and only if they are independent of the compact star’s internal structure, or more specifically, independent of its equation of state…. Thus, we say that compact stars are approximately bald or follicly challenged.”