Astrophysicists Find No ‘Hair’ on Black Holes

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. With new data, it has started to become possible to test this no-hair conjecture.

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