Astronomers have achieved the first direct evidence of a spinning black hole, shedding new light on these mysterious cosmic entities. This discovery centers on the supermassive black hole situated at the heart of the neighboring Messier 87 galaxy. This black hole was previously imaged by the Event Horizon Telescope. Supermassive black holes like the one in M87 often produce powerful jets of particles that are ejected into intergalactic space at nearly the speed of light. Scientists had hypothesized that the spin of a black hole powers these cosmic jets, but direct evidence was lacking until now.
The black hole in M87 is located 55 million light-years from Earth and is a staggering 6.5 billion times more massive than the Sun. Surrounding this black hole is an accretion disk composed of gas and dust, which swirls on the brink of this cosmic abyss. Some of this material falls into the black hole, disappearing forever, while a portion is expelled from the black hole’s poles at speeds exceeding 99.99% of the speed of light.
Theoretical models have suggested that the spin of the black hole drives this phenomenon. Charged particles within the disk create a powerful magnetic field, and as the black hole rotates, it drags this field with it. This action winds up the magnetic field, accelerating particles away from the black hole as jets. In the process, energy is extracted from the black hole’s rotation.
The recent research, published in Nature, used observations of M87 gathered from a global network of radio telescopes spanning from 2000 to 2022. These observations revealed an 11-year cycle in the jet, demonstrating that it precesses around a central point near the black hole’s edge. This precession indicates a misalignment between the black hole’s spin axis and the accretion disk, causing the jet to wobble, much like a spinning top.
The detection of this precession offers unequivocal evidence that the supermassive black hole in M87 is indeed spinning, enhancing our understanding of these cosmic giants. This discovery could also provide insights into the cataclysmic events that led to the formation of this supermassive black hole, as its spin and tilt suggest a turbulent past.