The supermassive black hole at the center of the Messier 87 galaxy, known as M87*, continues to reveal its secrets. A new study, using data from the Event Horizon Telescope (EHT), has determined that this black hole is spinning at about 80% of the maximum speed allowed by the laws of physics.
NASA, as part of ongoing research in astrophysics and astronomy, is closely monitoring the rotation of black holes and what relationship there may be between general relativity. Space observation is important, once again, to know the event horizon and study all the details of the universe.
When was M87* identified: all its history since 2019
M87* was the first directly imaged black hole, in 2019. Since then, it has become a benchmark for black hole research. With a mass equivalent to 6.5 billion times that of the Sun, its immense gravity shapes the entire galaxy around it.
By analyzing the difference in brightness between the two sides of the surrounding plasma ring, the researchers identified a relativistic Doppler effect: the light emitted by the material moving toward us appears brighter than that of the material moving away.
A new stage in the study of black holes
“The direct imaging of M87* marked a new stage in the study of black holes, allowing increasingly accurate tests of the theory of general relativity from multiple astronomical observations,” says José Luis Gómez, vice president of the EHT Scientific Council and leader of the EHT group at IAA-CSIC, vice president of the EHT Scientific Council and leader of the EHT group at IAA-CSIC, which includes Drs. Kotaro Moriyama, Thalia Traianou, Antonio Fuentes, and Antxon Alberdi, as well as predoctoral researchers Rohan Dahale, Marianna Foschi, and Teresa Toscano, and former members Ilje Cho, Rocco Lico, and Guang-Yao Zhao.
“The advancement of science implies a constant improvement in data quality and analysis techniques,” emphasizes Rohan Dahale, a predoctoral researcher at IAA-CSIC, and a key contributor to the new EHT results. “The integration of the Greenland Telescope into the EHT network has been essential in refining our images of M87* in 2018. For observations carried out in 2021, 2022 and the upcoming ones in 2024, further significant improvements have also been implemented that inspire us to continue to push the boundaries in black hole astrophysics.”
The average speed according to the scientists: about 42 million meters per second
This contrast allowed the scientists to estimate the speed of the plasma orbiting closest to the black hole: about 42 million meters per second, or 14% of the speed of light. From that, they calculated the spin parameter of M87*, a measure of how fast a black hole rotates. The result: 0.8 on a scale of 0 to 1, with 1 being the theoretical maximum. In fact, the researchers believe that this value could be a lower limit: M87* could be spinning even faster.
What does this discovery mean?
This rapid rotation has important implications. It affects the formation of powerful relativistic jets – streams of particles ejected from the center of the galaxy – and helps explain how black holes interact with their surroundings. Most importantly, the method used in this study could now be applied to other black holes observed by the EHT.
New analysis tools to learn more about black holes
The data analysis has incorporated eight independent imaging and modeling techniques, including both methods used in the previous analysis of M87* in 2017 and new ones developed from the experience gained from the analysis of Sgr A*, the black hole located at the center of the Milky Way.
The robustness of the obtained image is significantly strengthened by the diversity of image reconstruction and modeling techniques used. The consistency in the image morphology, demonstrated by the five mapping and three modeling methods, significantly strengthens the reliability of our results.”