Images captured over several years of the black hole known as M87* have revealed extraordinary and unprecedented changes in its magnetic field. Utilizing data from the Event Horizon Telescope gathered in 2017, 2018, and 2021, researchers have documented a complete reversal in the polarization of the magnetic field surrounding this supermassive black hole, indicating a dynamic cosmic environment outside its event horizon. This discovery marks the first time such significant alterations have been observed in relation to a black hole.
M87* resides approximately 55 million light-years from Earth and boasts a mass around 6.5 billion times that of the Sun. It has become the central focus of the Event Horizon collaboration, which aims to image supermassive black holes. Since the release of the first iconic image in 2019, scientists have continued to monitor M87*, analyzing data to observe changes in the mass of hot material swirling near the black hole. These observations include some of the most detailed studies of the jets projected from the poles of an active black hole.
“Jets like the one in M87* play a key role in shaping the evolution of their host galaxies,” stated Eduardo Ros, an astronomer at the Max Planck Institute for Radioastronomy in Germany. He explained that such jets regulate star formation and distribute energy over vast distances, impacting the lifecycle of matter on a cosmic scale.
The jets are believed to form through the black hole’s magnetic field, which influences the swirling material. As this material collects into a disk around the black hole, some of it is deflected along magnetic field lines, accelerating toward the poles and launching into space at speeds approaching that of light. These jets can extend for millions of light-years into the cosmos.
To analyze the dynamic environment around M87*, the Event Horizon Telescope collaboration conducted a series of observations over several years, focusing particularly on the polarization of light emitted in this magnetized region. When light traverses a strongly magnetized environment, its waves can become aligned in a specific direction. While images of M87* may appear relatively unchanged over time, the polarization data reveal significant variations.
In 2017, the magnetic fields appeared to spiral clockwise, but by 2018, they had shifted to an anti-clockwise orientation before stabilizing. By 2021, the pattern reverted to an anti-clockwise spiral. These findings indicate that the magnetic fields surrounding M87* change rapidly, even as the black hole itself remains stable.
“What’s remarkable is that while the ring size has remained consistent over the years—confirming the black hole’s shadow predicted by Einstein’s theory—the polarization pattern changes significantly,” noted Paul Tiede from the Harvard & Smithsonian Center for Astrophysics. He emphasized that the magnetized plasma near the event horizon is dynamic and complex, challenging existing theoretical models.
The new research outlines a turbulent environment characterized by fluctuating magnetic fields, which direct the flow of material around the black hole. Some of this material is pulled beyond the event horizon, while other portions are expelled into space as powerful jets.
Looking ahead, the Event Horizon Telescope team is preparing for an ambitious series of rapid observations scheduled for March and April 2026. The goal is to capture the first moving images of M87*, a long-awaited endeavor since the release of the initial black hole image.
“Pioneering a new frontier in time-domain black hole astrophysics, we are excited to be gearing up to capture the first movie of M87*,” said Remo Tilanus from The University of Arizona’s Steward Observatory. The findings from these studies have been published in the journal Astronomy & Astrophysics, contributing significantly to our understanding of black holes and their surrounding environments.
