💫 Black hole M87* shows rapid and unexpected transformation

One of the first black holes ever imaged, M87*, located at the heart of the Messier 87 galaxy 55 million light-years from Earth, continues to surprise astronomers with its behavior. New observations reveal unexpected transformations in its immediate environment.

Images captured by the Event Horizon Telescope (EHT) collaboration in 2017, 2018, and 2021 show significant variations in the magnetic fields surrounding M87*. These fields, which are regions of space where magnetic forces act on matter, appear in polarized light, meaning that the light waves are oriented in a specific direction. Scientists are analyzing this data to understand how these structures influence the accretion disk, a ring of superheated plasma swirling around the black hole.


According to Sebastiano von Fellenberg, former researcher at the Max Planck Institute for Radio Astronomy in Germany, the observed changes in polarization indicate that the black hole's environment is evolving rapidly, potentially in just a few weeks. This variability contrasts with the stability of the total intensity images, which show the constant mass and gravity of M87*. Researchers hope to produce more frequent image sequences in the future, similar to a film, to better capture these dynamics.

A major discovery concerns a specific polarization measurement in 2021, which showed a complete reversal compared to previous years. This phenomenon, where the orientation of magnetic fields flips, could be due to alterations in the magnetic structure itself, variations in Faraday rotation (an effect that modifies the polarization of light passing through a magnetized medium), or changing contributions from different emission regions like the disk or the jet. Scientists are exploring these hypotheses to elucidate this mystery.

These observations help better understand how magnetic fields around supermassive black holes, like M87* which weighs more than six billion times the mass of the Sun, can accelerate matter into jets at speeds close to that of light. These jets, stabilized by magnetic fields, play a key role in galaxy evolution by influencing star formation and energy distribution, opening new pathways for studying the cosmic impact of black holes.