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. Astronomers have detected hundreds of signals from colliding black holes over the past 10 years. In these dramatic even