Recent observations have revealed that the black hole known as M87* is undergoing significant and unprecedented changes in its magnetic field. Using data collected from the Event Horizon Telescope across multiple years—specifically in 2017, 2018, and 2021—scientists have mapped alterations in the polarization of M87*’s magnetic field. While the black hole itself remains stable, the environment surrounding it is dynamic, with extraordinary cosmic phenomena occurring just outside its event horizon.
Researchers discovered that between 2017 and 2021, the magnetic field around M87* completely flipped direction, marking the first time such a transformation has been documented in the vicinity of a black hole. This discovery is crucial for understanding how supermassive black holes, like M87*, feed on surrounding material and generate the powerful jets that propel matter into intergalactic space.
Significance of M87* in Astrophysics
M87* is a supermassive black hole located approximately 55 million light-years away in the Virgo galaxy cluster. It has a mass around 6.5 billion times that of the Sun, making it an ideal subject for study. Since the release of the first iconic image of M87* in 2019, the Event Horizon collaboration has continued to monitor this celestial object to gain insights into the mass of hot material swirling around its edge.
Astronomer Eduardo Ros from the Max Planck Institute for Radioastronomy emphasizes the importance of these jets, stating, “Jets like the one in M87 play a key role in shaping the evolution of their host galaxies.” By influencing star formation and distributing energy across vast distances, these jets significantly affect the cosmic lifecycle of matter.
Mapping Changes in the Magnetic Field
The magnetic field of a black hole is believed to be integral in creating its jets. As material spirals towards the black hole, it forms a disk around the equator. Not all of this material crosses the event horizon; some is channeled along the magnetic field lines into jets that are launched at near-light speeds. These jets can extend for millions of light-years.
To better understand the formation of these jets, the Event Horizon Telescope collaboration undertook a series of observations of M87* over several years. The team focused on the polarization of light emitted from the black hole’s vicinity. Light traveling through a magnetized environment can become organized, revealing patterns that are not immediately visible.
Although images of M87* appeared relatively consistent over the years, the polarization data unveiled remarkable changes. In 2017, the magnetic fields spiraled clockwise; by 2018, they shifted to an anti-clockwise direction, stabilizing in pattern. In 2021, the fields reverted to an anti-clockwise spiral. This suggests that the magnetic fields surrounding M87* are not static but change dramatically on short cosmic timescales.
Paul Tiede from the Harvard & Smithsonian Center for Astrophysics noted, “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.” This observation indicates that the magnetized plasma surrounding the event horizon is dynamic and complex, challenging current theoretical models.
The findings unveil an ever-changing environment around supermassive black holes, showing how turbulent magnetic fields can direct the flow of material. Some of this material is drawn beyond the event horizon, while some is expelled into space as powerful jets.
Future studies aim to build on these findings. Remo Tilanus from the University of Arizona’s Steward Observatory announced plans for a series of rapid observations in March and April 2026. “We are excited to be gearing up to capture the first movie of M87*, something that has been on our wish list ever since that first image of a black hole,” he stated.
This research has been published in the journal Astronomy & Astrophysics, contributing significantly to the field of astrophysics and enhancing our understanding of these enigmatic cosmic giants.
