A Black Hole Has Been Firing a Plasma Jet at Earth From 12,000 Light-Years Away

Hidden in Plain Sight for Decades

Astronomers have discovered the first microblazar in the Milky Way — a black hole-powered particle accelerator that is blasting near-light-speed plasma jets directly at Earth. The discovery, published in the journal Astronomy & Astrophysics, marks the culmination of a search that has taken scientists roughly three decades. And the object responsible had been catalogued and largely forgotten long before anyone realized what it truly was.

The binary system known as IRAS 18293−0941 sat behind a dense wall of interstellar gas and dust, making it essentially invisible in ordinary optical images. Although the Infrared Astronomical Satellite originally detected the object in 1983, it attracted little attention for decades. "Everything about IRAS 18293−0941 was hiding in plain sight," said research leader Josep Martí of the University of Jaén, Spain. The cosmic equivalent of a needle in a haystack — except the haystack was made of interstellar dust thick enough to fool astronomers for forty years.

What Exactly Is a Microblazar?

A microblazar is a binary system where a stellar-mass black hole siphons material from a companion star, forming an accretion disk and launching jets of matter and radiation at near-light speeds. The difference between a blazar and a microblazar is that the former consists of a supermassive black hole with a mass millions or billions of times that of the sun, feeding on surrounding matter and firing jets directly at Earth. Think of it as a scaled-down version of one of the universe's most violent phenomena — right here in our own galactic backyard.

The system is located around 12,000 light-years away and consists of a black hole feeding on material stripped from a massive companion star, which it orbits every 11 Earth days. IRAS 18293−0941 contains a roughly 10-solar-mass black hole whose Earth-directed jet identifies it as the first Milky Way microblazar. One of its two jets happens to point almost directly toward Earth, making the discovery possible. To be clear, at about 12,000 light-years away, IRAS 18293−0941 is a research opportunity, not a hazard. The favorable alignment lets scientists inspect jet physics in far greater detail than they can for distant blazars.

How the Discovery Was Made

The breakthrough began when astronomers noticed the light of the system's star flickering. That flicker revealed an 11-day orbital period for a companion black hole, which scientists realized they were observing almost face-on. From there, the team built a case piece by piece. High-resolution observations made using the network of radio telescopes called the European VLBI Network (EVN) confirmed the orientation of the jet and that it originated from the system IRAS 18293−0941. "This was the moment the result became solid," explained Benito Marcote from the Joint Institute for VLBI in the Netherlands. "The resolution achieved by the EVN position together with the known position of the star from the Gaia satellite confirmed it: the jet belongs to the stellar system."

The research team combined data from radio, optical, X-ray, gamma-ray, and infrared telescopes to confirm the discovery. Jakob van den Eijnden of the University of Amsterdam summed it up: "None of the individual telescopes could have told the entire story. It's a great showcase of international teamwork."

A Cosmic Particle Accelerator — and What It Means

The researchers also identified the region where the jet hits a molecular cloud as a place where particles are accelerated to ultra-high energies, likely up to petaelectronvolts — which would make microblazars one of the most powerful particle accelerators in the galaxy. For context, this makes microblazars some of the Milky Way's most powerful particle accelerators, about 100 times stronger than Earth's Large Hadron Collider. The jet is estimated to carry around 500,000 times the energy released by the Sun.

The discovery helps identify where the most energetic particles in our galaxy come from. The jet that heats and ionizes molecular clouds may also affect the way in which stars form. And studying a local microblazar allows scientists to obtain an understanding of the physics involved in the much larger blazars driven by supermassive black holes in distant galaxies. In other words, this single hidden object could serve as a Rosetta Stone for some of the biggest mysteries in astrophysics — from the origins of cosmic rays to how galaxies evolve. Scientists who have spent careers studying blazars billions of light-years away now have one they can examine up close, and the implications of that proximity are only beginning to unfold.