Tracing the Fire: How Astronomers Followed a Black Hole's 3,000-Light-Year Jet Back to Its Source

On April 10, 2019, the world saw the first-ever image of a black hole — a blurry orange ring surrounding the supermassive object at the heart of galaxy Messier 87. Seven years later, the same collaboration has taken a significant next step: tracing the origin point of the colossal jet that this black hole fires into intergalactic space.

A study published January 28, 2026 in Astronomy & Astrophysics identifies a compact radio source roughly 0.09 light-years (about 5,500 astronomical units) from the black hole M87*, which the researchers describe as the "probable position" of the base of the jet that stretches approximately 3,000 light-years into space [1][2]. The finding bridges, for the first time, the now-iconic shadow image of the black hole with the large-scale jet it produces — a connection astrophysicists have pursued for decades.

The Black Hole and Its Jet

M87* sits at the center of the giant elliptical galaxy Messier 87, approximately 55 million light-years from Earth in the Virgo cluster. With a mass estimated at 6.5 billion times that of the Sun, it ranks among the most massive black holes known [3][4].

The jet emanating from M87* was first photographed in 1918 by astronomer Heber Curtis, who described it as "a curious straight ray" extending from the galaxy's nucleus. More than a century later, we know this structure is a relativistic jet — a narrow beam of plasma accelerated to near light speed — that extends roughly 3,000 light-years from its source [2][5]. At radio wavelengths, the jet has been observed stretching even farther, with structures detectable across tens of thousands of light-years.

Among relativistic jets studied in astrophysics, M87's is one of the most accessible because of its relative proximity and its orientation partly toward Earth, which makes fine-scale features easier to resolve. Other well-studied jet systems, such as Centaurus A (about 12 million light-years away) and the blazar 3C 279, have provided complementary data, but M87's combination of mass, proximity, and jet power makes it the primary laboratory for understanding jet physics [6].

What Changed: The 2021 EHT Campaign

The Event Horizon Telescope is not a single instrument but a network of radio observatories spanning the globe, linked through a technique called Very Long Baseline Interferometry (VLBI). VLBI combines signals from widely separated telescopes to simulate a dish the size of the Earth, achieving angular resolution fine enough to read a newspaper in New York from a café in Paris [3].

The original 2017 observations that produced the famous black hole image used eight telescope stations. By 2021, two additions changed the array's capabilities: the 12-meter Kitt Peak Telescope in Arizona and the Northern Extended Millimeter Array (NOEMA) in the French Alps [1][7].

Source: Event Horizon Telescope Collaboration

Data as of Jan 28, 2026CSV

These new stations did not merely add sensitivity — they filled a gap in what astronomers call "baseline coverage." The EHT's longest baselines (thousands of kilometers) resolve the finest structures, like the black hole's ring. But emission from the jet base occupies an intermediate angular scale — too large for the longest baselines and too small for a single dish. The Kitt Peak and NOEMA stations provided baselines of a few hundred to a few thousand kilometers to the Submillimeter Telescope (SMT) and the IRAM 30-meter telescope, respectively, giving the array sensitivity to structures at scales of approximately 250 and 2,500 microarcseconds [1][7].

"The 2017 and 2018 EHT observations lacked the intermediate baselines to detect it," the researchers noted. The 2021 campaign's expanded configuration made it possible to constrain, for the first time with the EHT at 230 GHz, the emission direction of the base of M87's relativistic jet [7][8].

What They Found

The analysis, led by Saurabh at the Max Planck Institute for Radio Astronomy (MPIfR) in Bonn, along with Hendrik Müller of the National Radio Astronomy Observatory (NRAO) and Sebastiano von Fellenberg of the Canadian Institute for Theoretical Astrophysics (CITA), reveals a Gaussian emission feature centered at approximately 320 microarcseconds in right ascension and 60 microarcseconds in declination from M87* [1][8]. This corresponds to a projected separation of about 5,500 AU — roughly 0.09 light-years — from the black hole itself.

The detected flux density of this feature is approximately 60 milliJansky, faint compared to the ~0.5 Jansky brightness of the ring itself [8]. This compact emission aligns with structures seen in earlier radio-frequency maps at lower frequencies, where the jet base had been imaged at coarser resolution.

"This study represents an early step toward connecting theoretical ideas about jet launching with direct observations," lead author Saurabh stated. "Identifying where the jet may originate and how it connects to the black hole's shadow adds a key piece to the puzzle and points toward a better understanding of how the central engine operates" [2][4].

The Decades-Long Theoretical Debate

How black holes launch jets has been one of the central questions in high-energy astrophysics since the 1970s. Three broad classes of models have competed for prominence.

The Blandford-Znajek (BZ) mechanism, proposed by Roger Blandford and Roman Znajek in 1977, holds that energy is extracted electromagnetically from a spinning black hole. Strong magnetic fields, anchored in the surrounding accretion disk, thread the black hole's ergosphere — the region just outside the event horizon where spacetime is dragged by the hole's rotation. The interaction between the magnetic field and the spinning spacetime generates a Poynting flux (electromagnetic energy flow) that accelerates plasma along the rotation axis [9][10].

The Blandford-Payne (BP) mechanism, proposed in 1982, extracts energy not from the black hole's spin but from the accretion disk itself. Magnetic field lines rooted in the disk fling material outward centrifugally, producing a disk-driven wind that can collimate into a jet [10].

A third possibility involves magnetic reconnection — the rapid rearrangement of magnetic field lines near the black hole, which converts magnetic energy directly into particle kinetic energy. Recent computational work has suggested this may operate as a second channel alongside the BZ process, with both contributing to the total jet power [10].

The EHT's 2021 polarization images of M87* already showed strong, ordered magnetic fields at the event horizon scale, consistent with a magnetically arrested disk (MAD) state — a configuration in which magnetic pressure near the black hole becomes dynamically important. This supported the BZ mechanism as the dominant jet-launching process [9][10].

The new jet-base detection adds another piece. The location and orientation of the compact emission is consistent with predictions from general relativistic magnetohydrodynamic (GRMHD) simulations of BZ-driven jets. However, the researchers stop short of ruling out a contribution from disk-driven winds at larger scales. Some theoretical models predict a nested structure — an inner BZ-powered spine surrounded by an outer BP-driven sheath — and the current data cannot fully distinguish between these scenarios [8][10].

Scrutinizing the Claim: Could It Be an Artifact?

The researchers themselves flag an important caveat: the 2021 observations include only two intermediate baselines, which limits the ability to reconstruct the morphology of the jet base. The recovered Gaussian feature is treated as an upper limit on the jet base flux density, not a definitive image of the structure [8].

This raises a legitimate question: could the detected emission be an artifact of the sparse baseline coverage rather than a genuine astrophysical source?

The team addresses this through multiple analysis pathways. They tested the detection using different imaging algorithms and visibility-domain fitting methods, finding that the compact feature appeared consistently across approaches [8]. They also compared the position and flux density against predictions from lower-frequency VLBI observations (at 43 GHz and 86 GHz), where the jet base has been better characterized with denser baseline coverage. The 230 GHz detection falls within the expected range extrapolated from these measurements [1][7].

Still, as the paper acknowledges, "coverage from only two intermediate baselines limits reconstruction of its morphology" [8]. Future observations with expanded intermediate-baseline coverage — potentially from the next-generation EHT — will be needed to confirm the structure and determine whether it truly represents the jet's launching point rather than an intermediate knot or shock feature within the flow.

Energy Transfer Across Cosmic Scales

If the jet base is indeed located approximately 0.09 light-years from M87*, the finding poses a striking physical question: how does a process occurring in a region smaller than our solar system maintain coherence and transfer energy across 3,000 light-years?

Relativistic jets carry energy primarily in two forms: the kinetic energy of the bulk plasma flow and the electromagnetic energy stored in the magnetic field. For M87, estimates of the jet's total power range from 10^{42} to 10^{44} ergs per second — comparable to the luminosity of an entire galaxy [6][9].

This energy does not remain contained within the jet. As it propagates through the host galaxy and beyond, the jet deposits energy into the surrounding gas through shocks, turbulence, and direct heating. This process, known as AGN feedback (where AGN stands for Active Galactic Nucleus), is now considered a central mechanism in galaxy evolution [11].

In galaxy clusters like Virgo, where M87 resides, the hot intracluster gas should theoretically cool and condense, forming new stars at high rates. Observations show this cooling is largely suppressed. The leading explanation is that jets from central black holes inject enough energy to offset radiative cooling — acting as a thermostat that regulates star formation across the cluster [11]. Radio observations of M87 itself show cavities and bubbles inflated by the jet in the surrounding X-ray-emitting gas, direct evidence of this energy deposition [6].

Understanding exactly where and how the jet is launched therefore has implications far beyond M87. The efficiency of energy extraction from the black hole, the collimation geometry, and the magnetic field structure at the jet base all determine how much energy ultimately reaches the intergalactic medium — and therefore how effectively jets regulate galaxy growth across the cosmos.

The Cost of Seeing the Invisible

Source: OpenAlex

Data as of Jan 1, 2026CSV

The EHT collaboration comprises over 300 researchers across more than 60 institutions in over 20 countries [3]. Its operations depend on simultaneous allocation of observing time at some of the world's most in-demand telescope facilities, including ALMA (the Atacama Large Millimeter/submillimeter Array), which is itself an international partnership among the European Southern Observatory, the U.S. National Science Foundation, and Japan's National Institutes of Natural Sciences [7].

Funding for the EHT has come from a patchwork of national and international sources, including the NSF, the Max Planck Society, and European Commission programs such as BlackHoleCam, M2FINDERS, and JETSET [3][12]. A precise total cost is difficult to calculate because many contributing observatories were built and operated for broader purposes, with EHT observations consuming only a fraction of their annual schedule.

The next-generation EHT (ngEHT) aims to expand the network significantly, adding new dedicated dishes and upgrading existing facilities. The NSF has awarded a $12.7 million grant for the ngEHT design program, which would enable not just sharper still images but real-time video of material flowing around black holes [12]. The ngEHT would also fill the intermediate-baseline gaps that currently limit jet-base observations — directly addressing the limitations of the current study.

Whether this level of investment is scalable across the dozens of jet systems identified by surveys is an open question. The EHT's planet-wide coordination requirements — synchronizing observations across time zones, weather conditions, and institutional schedules — represent a logistical challenge that grows with each added target. However, improvements in data recording bandwidth and the addition of permanent ngEHT stations could reduce per-observation costs and make multi-target campaigns more feasible [12].

Academic interest in jet physics continues to grow. More than 50,700 papers on black hole jets have been published since 2011, with annual output peaking at 6,214 in 2023, according to OpenAlex data. The 2019 black hole image marked a visible inflection point, with publication rates accelerating sharply afterward [13].

What Comes Next

The 2026 result is explicitly framed by its authors as a "first hint" rather than a final answer. The team plans continued observations of M87* with both the current EHT and the ngEHT, incorporating multi-frequency observations that could map the jet base's spectral properties and magnetic field structure [1][7].

"It is amazing to see that we are gradually moving towards combining these breakthrough observations across multiple frequencies and completing the picture of the jet launching region," one team member stated [5].

The ultimate goal is to connect the black hole's event-horizon-scale physics — its spin, magnetic field, and accretion rate — to the large-scale jet in a single, observationally verified chain. For M87*, with its century-long observational history and unmatched multi-wavelength coverage, that chain is closer to complete than for any other black hole system. But as the researchers acknowledge, the final links remain to be forged.