Event Horizon Telescope Resolves Tangled Magnetic Fields Swirling Around Supermassive Black Hole Sagittarius A*

The Three-Question Framework

What Happened?

The global Event Horizon Telescope (EHT) collaboration published new polarized-light images of Sagittarius A*, the supermassive black hole at the center of our Milky Way galaxy. By analyzing polarized synchrotron radiation emitted by relativistic electrons in the surrounding plasma, the astronomical array mapped the geometry and orientation of magnetic field lines swirling around the event horizon.

Why It Matters

While Sagittarius A* is over 1,500 times smaller and less active than the gargantuan black hole in galaxy M87*, the EHT polarization map reveals nearly identical geometric spiral magnetic field structures. This provides direct empirical proof that strong, geometrically organized magnetic fields are an intrinsic physical feature of all accreting black holes, governing how matter falls into the singularity and how relativistic energy is channeled.

What Could Happen Next

Astronomers are integrating additional ground telescopes in Greenland and France while preparing the next-generation EHT (ngEHT) to capture the first continuous high-framerate video of plasma swirling around Sagittarius A* in real time.

Executive Key Takeaways

First polarized view: maps the magnetic field architecture around the Milky Way's central supermassive black hole.

Universal magnetic signature: identical spiral polarization patterns found in both Sagittarius A* and M87*.

Relativistic plasma physics: confirms that magnetic fields mediate plasma accretion and jet launching mechanisms.

Global baseline: synthesized an Earth-sized virtual telescope combining eight millimeter-wavelength observatories.

On August 19, 2026, the Event Horizon Telescope (EHT) collaboration released groundbreaking polarized images of Sagittarius A*, revealing the intense, swirling magnetic field lines that govern the center of the Milky Way galaxy.

Two years after capturing the first direct shadow of Sagittarius A*, researchers analyzed the linear polarization of millimeter-wavelength light emitted by relativistic electrons spiraling through magnetized plasma near the event horizon. Because light becomes polarized perpendicular to the local magnetic field direction, mapping polarization angles reconstructs the underlying magnetic field lines in curved spacetime.

The resulting image reveals sharp, tightly wound spiral polarization patterns tracing the inner edge of the photon ring. Despite Sagittarius A* possessing a mass of 4.3 million suns—vastly smaller and quieter than the 6.5-billion-solar-mass black hole M87*—the two black holes exhibit virtually identical magnetic field topologies.

This structural similarity strongly suggests that strong, ordered magnetic fields are universal properties of black hole accretion disks, regardless of mass, galaxy environment, or accretion rate. These fields generate magnetohydrodynamic pressures that channel gravitational energy and may power an undiscovered, faint relativistic jet emanating from our galaxy's center.

The observations provide a crucial test of General Relativity in the extreme gravitational regime, affirming Einstein's equations at the ultimate cosmic frontier.