Recent Observations of the M87* Black Hole by the Event Horizon Telescope (EHT) – Eight Ground-Based Radio Telescopes (ALMA, APEX, Iram 30 m Telescope, James Clerk Maxwell Telescope, Lage Millimeter Telescope Alfonso Serrano, Submillimeter Array Telescope) – Unveil a dynamic environment with varying polarization patterns near black holes.
The EHT images show that the magnetic field of M87* spiraled in one direction in 2017, settled in 2018, and reversed direction in 2021. Image credit: EHT collaboration.
Messier 87 is a vast elliptical galaxy situated approximately 53 million light-years away in the Virgo constellation.
This galaxy, also known as M87, houses the M87*, an ultra-massive black hole with a mass exceeding 6 billion solar masses.
In 2017, the EHT Collaboration detected a helical polarization pattern, indicating large-scale twisted magnetic structures, confirming long-held hypotheses about black hole interactions and their surrounding environments.
However, by 2018, the polarization nearly vanished. In 2021, a faint remnant began to spiral in the opposite direction.
Astrophysicists are now grappling with the pivotal question: Why?
“Black holes hold mysteries tightly, yet we continue to seek answers from their grasp,” stated Professor Avery Broderick, an astrophysicist at the University of Waterloo and the Perimeter Institute.
“Our team at Waterloo is reconstructing images from EHT data and determining what we can confidently assert—distinguishing between realistic findings and potential instrumental artifacts.”
“We are at the forefront of deciphering how EHT images, particularly their evolution, can unveil astrophysical dramas unfolding in the most extreme gravitational conditions.”
Each year, EHT collaborations revisit M87*, capturing fleeting moments that reveal its ongoing evolution, providing deeper insights into its well-guarded secrets.
“What’s intriguing is that the ring sizes have remained consistent over the years, validating the shadows of black holes predicted by Einstein’s theory, while the polarization patterns change dramatically,” remarked Dr. Paul Thierde, an astronomer at the Harvard & Smithsonian Center for Astrophysics.
“This indicates that the magnetized plasma swirling near the event horizon is not static but dynamic and complex, challenging theoretical models.”
The stability of M87*’s shadow serves as evidence that “black holes have no hair,” implying that a black hole is a simple geometric entity defined exclusively by mass, spin, or charge.
“This simplicity makes it an intriguing object of study within gravity, allowing for precise predictions. Other astrophysical phenomena seem secondary,” elaborated Professor Broderick.
“However, the surrounding environment can exhibit ‘hair,’ with magnetic fields being notable examples.”
“We have long understood what types of magnetic structures could exist, but now we believe there’s a rich diversity of configurations that can change rapidly, similar to human hairstyles.”
“These findings illustrate how EHT is maturing into a full-fledged scientific observatory that not only produces unprecedented images but also fosters a continuous and coherent understanding of black hole physics.”
“Each new observational campaign broadens our understanding, from the dynamics of plasma and magnetic fields to the role of black holes in the evolution of cosmic structures.”
“This is a concrete demonstration of the extraordinary scientific potential of this infrastructure.”
The survey results will be published in the journal Astronomy and Astrophysics.
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Kazunori Akiyama et al. (Event Horizon Telescope Collaboration). 2025. 2017-2021 Horizon scale variation of M87* from EHT observations. A&A in press; doi: 10.1051/0004-6361/202555855
Source: www.sci.news
