A global team of astronomers has produced the first image that captures both the glowing ring of matter around a supermassive black hole and the base of the powerful jet it launches into space, revealing in a single frame how inflowing gas transforms into an outbound stream of plasma traveling near the speed of light.
The target was M87*, the 6.5-billion-solar-mass black hole at the heart of the galaxy Messier 87, roughly 55 million light-years from Earth. The same object made headlines in 2019 when the Event Horizon Telescope (EHT) delivered humanity’s first direct image of a black hole shadow. That portrait, captured at a wavelength of 1.3 mm, showed the shadow in stunning detail but could not reveal how the black hole’s surroundings connect to the relativistic jet that extends tens of thousands of light-years beyond the galaxy’s core.
Now, observations at a longer wavelength of 3.5 mm have bridged that gap. The results, led by astronomer Ru-Sen Lu of the Shanghai Astronomical Observatory and published in Nature, show a bright, ring-like accretion structure surrounding the black hole with the jet’s root emerging from its inner edge. “For the first time, we can see how the jet connects to the accretion disk around the black hole,” Lu said when the findings were announced.
A planet-sized instrument
To pull off the observation, the team used a technique called very long baseline interferometry (VLBI), combining signals from radio telescopes scattered across multiple continents so they function as a single dish nearly the diameter of Earth. The backbone was the Global Millimetre VLBI Array (GMVA), a network of facilities in Europe, the United States, and East Asia. Two critical additions sharpened the view: the Atacama Large Millimeter/submillimeter Array (ALMA) in Chile’s Atacama Desert and the Greenland Telescope, perched on the island’s ice sheet. Together, these stations provided the angular resolution needed to peer into the zone where the jet forms.
The choice of 3.5 mm wavelength was deliberate. The EHT’s 1.3 mm observations offered the sharpest possible view of the shadow ring but captured too narrow a field to include the jet’s launch region. By shifting to a longer wavelength, the GMVA team traded a small amount of resolution for a wider perspective, fitting both the compact ring and the extended jet base into the same image. The two wavelengths are complementary: one zooms in on the shadow, the other pulls back just enough to catch the moment matter stops falling inward and starts streaming outward.
The imaging was validated across multiple independent reconstruction pipelines, as detailed in the freely accessible preprint of the Nature paper. The ring-like structure and jet base persisted regardless of which algorithm or parameter set the team applied, ruling out the possibility that the features are artifacts of any single processing method.
Why the ring-jet connection matters
Astrophysicists have long debated how black holes launch jets. The leading theoretical frameworks, developed by Roger Blandford and Roman Znajek in the 1970s and later refined by others, propose that magnetic fields threading either the spinning black hole or its accretion disk extract rotational energy and funnel it into a narrow, high-speed outflow. But until now, the transition zone where disk becomes jet had only been explored through computer simulations.
The new image provides the first observational anchor for those models. The jet appears to originate from the inner edge of the accretion flow, the region where matter is still gravitationally bound to the black hole. That geometry is consistent with magnetically driven launch mechanisms and places real constraints on the density, temperature, and magnetic field configuration of the gas. Simulations that attempt to reproduce both the accretion ring and the jet now have a direct benchmark to match.
The result also offers a new way to study how efficiently black holes convert infalling matter into outgoing energy. M87’s jet is among the most powerful known, carrying enough energy to inflate enormous bubbles of hot gas in the surrounding galaxy cluster. Understanding the physics at its base could help explain how jets regulate the growth of galaxies across cosmic time, a process known as AGN feedback that shapes the large-scale structure of the universe.
What the image does not settle
For all its detail, the image leaves several fundamental questions open. It cannot, on its own, distinguish whether the jet draws its energy primarily from the black hole’s spin or from magnetic processes rooted in the disk. Answering that will require polarization measurements that map the orientation and strength of magnetic fields near the jet base, data the team has indicated it is working to obtain.
Quantitative details about the jet’s acceleration profile remain limited as well. The published figures show how brightness varies along the jet, but precise velocity gradients at the jet’s root and error margins on energy conversion efficiency have not yet been reported in full. Claims about how rapidly the jet reaches relativistic speeds should be understood as qualitative for now.
There is also the question of how representative M87 is. Its black hole is exceptionally massive and sits in a giant elliptical galaxy at the center of the Virgo Cluster, an environment that may differ significantly from the settings of more typical active galaxies. Extending these observations to other targets across a range of black hole masses and accretion rates will be essential before the M87 result can be generalized. The EHT’s 2022 image of Sagittarius A*, the four-million-solar-mass black hole at the center of the Milky Way, demonstrated that VLBI can resolve very different systems, but Sgr A* does not produce a prominent jet, making direct comparison difficult.
What comes next for black hole imaging
Future observing campaigns aim to combine GMVA and EHT data at multiple wavelengths, tracking how emission regions shift with frequency to reveal particle energies and magnetic field strengths closer to the event horizon. Proposals for the next-generation EHT (ngEHT) call for additional stations that would sharpen resolution further and enable time-lapse movies of the accretion flow, potentially capturing the jet’s variability in real time.
For now, the 3.5 mm image of M87 stands as a reference point: the first clear snapshot of the region where a supermassive black hole’s inflowing matter turns into an outgoing cosmic jet. It does not close the book on jet physics, but it opens a chapter that was previously written only in theory. The data are public, the methods are documented, and the next round of observations is already being planned. The black hole, as always, is patient.
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*This article was researched with the help of AI, with human editors creating the final content.
