Scientists just proved that 'monster' black hole M87 is spinning

Scientists just proved that 'monster' black hole M87 is spinning — confirming Einstein’s relativity yet again
The discovery was made by studying powerful jets of energy emitted by the M87 black hole, which is located at the center of the neighboring Messier 87 galaxy.
M87 is the best-studied black hole to date and was the first to be directly imaged in 2019, revealing its characteristic "donut hole" shadow surrounded by a fuzzy halo of light.
Astrophysicists had long predicted that black holes should spin, but the challenge of imaging them made it difficult to gather direct evidence until now.
To study the spin of black holes, astronomers focused on the M87 supermassive black hole, which has a mass 6.5 billion times that of the sun.