Viewpoint: Simplicity of Black Holes

The Editors of \emph{Viewpoint} requested a brief report on Norman G\"urlebeck's recent results \cite{1} concerning black holes in astrophysical environments. The first draft I wrote assumed knowledge of general relativity at the level of a graduate-level course. But it was significantly simplified to make the final version \cite{viewpoint} accessible to undergraduates who are not familiar with general relativity. This submission to arXiv contains the first version that is likely to be more helpful to beginning researchers who are interested in black holes.