According to Einstein’s theory of gravity, black holes have only a small handful of distinguishing characteristics. Quantum theory implies they may have more. Now an experimental search finds that any of this extra ‘hair’ has to be pretty short.
Do black holes have a cookie-cutter form, or subtle distinctions that reveal each one’s unique history and makeup?
Celsius Pictor for Quanta Magazine
Introduction
According to Albert Einstein’s general theory of relativity, the behavior of a black hole depends on two numbers: how heavy it is, and how fast it is rotating. And that’s it. Black holes are said to have “no hair” — no features that distinguish them from their fellows with the same mass and spin.
