The first black hole ever to be captured in a direct image is now revealing its turbulent secrets. Astronomers have witnessed the magnetic field of M87* (“M-eighty-seven star”), a supermassive black hole at the center of the M87 galaxy, completely flip direction between 2017 and 2021. The observations mark the first time scientists have observed such dramatic change in the extreme environment surrounding a black hole. The discovery provides new clues about how these cosmic giants feed and power their enormous jets.
New images from the Event Horizon Telescope (EHT) collaboration have revealed a dynamic environment with changing polarization patterns in the magnetic fields of the supermassive black hole M87*. Magnetic fields appeared to spiral in one direction in 2017 (left), settle down after one year (middle) and reverse direction in 2021 (right).
Observations from the Event Horizon Telescope collaboration, published today in the journal Astronomy & Astrophysics, provide new insight into how matter and energy behave in the extreme environments surrounding black holes. University of Arizona astronomers played a key role in obtaining these results, using data from the Arizona Radio Observatory telescopes: the Submillimeter Telescope on Mt. Graham and the 12-meter Telescope on Kitt Peak, both in Southern Arizona.
Located about 55 million light-years away from Earth, the M87 galaxy harbors a supermassive black hole containing more than 6 billion times the mass of the sun. Black holes are concentrations of matter so dense that their gravity becomes strong enough that even light cannot escape. The only way to “see” a black hole is by observing its accretion disk, a ring of superheated plasma emitting electromagnetic radiation in wavelengths that can be detected with radio telescopes.
The EHT, a global network of radio telescopes acting as an Earth-sized observatory, first captured the iconic image of M87’s black hole shadow in 2019. Now, by comparing observations of polarized light patterns surrounding the black hole from 2017, 2018, and 2021, scientists have taken the next step toward uncovering how the magnetic fields near the black hole change over time.
“Without our persistent observations of M87* year after year, we would not be able to discover this remarkable behavior,” said Boris Georgiev, a postdoctoral fellow at the U of A’s Steward Observatory who contributed to the data processing and interpretation.
Polarized light differs from ordinary light, in that its waves oscillate in a single plane rather than multiple directions. When scientists observe polarized light from around a black hole, it reveals the structure and strength of magnetic fields in that region – crucial information for understanding how black holes consume matter and launch powerful jets into space. Between 2017 and 2021, the polarization pattern of M87’s black hole flipped direction. In 2017, the magnetic fields appeared to spiral one way. The fields settled by 2018, and in 2021 they reversed, spiraling the opposite direction.
“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,” said Paul Tiede, an astronomer at the Center for Astrophysics | Harvard & Smithsonian, and a co-investigator of the new study. “This tells us that the magnetized plasma swirling near the event horizon is far from static; it’s dynamic and complex, pushing our theoretical models to the limit.”
The cumulative effects of how this polarization changes over time suggests an evolving, turbulent environment where magnetic fields play a vital role in governing how the black hole feeds on matter and spits out energy into space.
Crucially, the 2021 EHT observations benefitted from enhanced sensitivity provided by two new telescopes joining the globe-spanning network: the U of A’s Arizona Radio Observatory on Kitt Peak southwest of Tucson, and the Northern Extended Millimeter Array in France. This improvement allowed scientists to detect emission from the base of M87’s relativistic jet – a narrow beam of energetic particles blasting from the black hole at nearly the speed of light.
“Detecting the jet emission this close to the black hole is like finally seeing the engine that powers these cosmic jets,” said Jasmin Washington, a doctoral student at Steward Observatory and one of the paper’s co-authors.
Amy Lowitz, an EHT scientist at Steward Observatory, added: “It connects what we see at the event horizon – the boundary past which no light can escape the black hole – with the giant jets extending thousands of light-years into space.”
“Adding the Kitt Peak 12-meter Radio Telescope is essential in capturing the large-scale structure in the resulting images,” said Dan Marrone, a professor of astronomy at the U of A and Steward Observatory. “These multi-year images deepen our understanding of one of the universe’s most extreme environments and help confirm Einstein’s predictions, while revealing new, unexpected complexities about magnetic fields and jet formation near a supermassive black hole.”
These findings help address one of astrophysics’ most enduring mysteries: how black holes transform infalling matter into powerful jets that influence entire galaxies.
“As infalling gas approaches the black hole at almost the speed of light, it picks up incredible amounts of energy and heats up to billions of degrees,” said Chi-Kwan Chan, astronomer at Steward Observatory. “Some of that gas isn’t swallowed, but launches back into space, which creates the jet emanating from the black hole. How this happens and what causes this to happen is still a mystery. Studies like this one help us better understand these processes, which likely involve extremely strong magnetic fields.”
Jets like M87’s play a crucial role in galaxy evolution because they distribute energy across vast scales throughout their host galaxies, directly affecting cosmic processes like star formation. The jet emits radiation across the electromagnetic spectrum – including gamma rays and neutrinos – providing a unique laboratory to study how these cosmic phenomena form and launch.
The Event Horizon Telescope collaboration continues to expand its observational capabilities to discover more about the evolving, turbulent environment surrounding supermassive black holes. “Pioneering a new frontier in time-domain black hole astrophysics, the EHT is planning an ambitious series of rapid-fire observations across March and April 2026,” said Remo Tilanus, a research professor at Steward and operations manager of the EHT collaboration. “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.”