When the Event Horizon Telescope (EHT) revealed the first-ever direct image of a black hole in 2019, the world was mesmerized by the fiery-orange donut of swirling gas. That monster, M87*, resides 55 million light-years away at the heart of the giant elliptical galaxy Messier 87.
But that famous image only showed the engine. The exhaust from that engine is arguably even more spectacular: a colossal jet of high-energy particles blasting out of the galaxy's core.
This structure is a testament to one of the most powerful and violent processes in the universe.
The Engine of Creation and Destruction
The jet originates from the direct vicinity of M87* a supermassive black hole (SMBH) weighing 6.5 billion times the mass of our Sun.
It’s a common misconception that black holes only "suck" things in. In reality, as a black hole feeds, it creates an "accretion disk" a swirling, chaotic platter of gas, dust, and shorn-apart stars heating up to billions of degrees as it spirals toward the event horizon.
This superheated maelstrom generates unfathomably strong, tangled magnetic fields. The M87* black hole itself is spinning, and this spin twists these magnetic fields into a tight, colossal funnel.
This magnetic funnel acts as a cosmic particle accelerator. It captures a fraction of the inbound, energized material a seething soup of plasma and redirects it, firing it away from the black hole's poles.
A Journey at the Speed of Light
The resulting jet is not just a gentle plume; it is a focused, terrifyingly powerful beam of matter.
Composition: The jet is composed of plasma a state of matter where atoms are stripped of their electrons traveling at relativistic speeds.
Speed: "Relativistic" means it is moving at over 99% the speed of light.
Appearance: This immense speed creates a "ghostly blue glow," which is a hallmark of synchrotron radiation. This light is produced when the super-fast electrons spiral around the magnetic field lines within the jet.
What we observe from Earth is not a smooth, uniform beam. Instead, the jet is full of bright "knots" and clumps. These are areas within the jet where massive shockwaves form, similar to a sonic boom, further energizing the particles and causing them to glow intensely.
Putting 5,000 Light-Years in Perspective
The sheer scale of this phenomenon is difficult to comprehend. The jet extends from M87’s core for 5,000 light-years.
To put that in perspective:
One light-year is approximately 6 trillion miles (9.5 trillion km).
The jet, therefore, stretches for roughly 30 trillion miles (47.5 trillion km).
This single beam, ejected from a "tiny" central point, is 20 times longer than the distance from our Sun to the center of our own Milky Way galaxy.
The M87 jet is more than just an astronomical curiosity. It is a vital force of cosmic feedback. This powerful beam slams into the gas and dust within the wider M87 galaxy, carving out huge cavities and potentially triggering or even preventing the formation of new stars.
It serves as a stunning, visual reminder that black holes are not just cosmic drains; they are the most powerful engines in the universe, actively shaping the galaxies they inhabit.