Black hole jets measured in real time for the first time, releasing the power of 10,000 suns

For decades, calculating the power of a black hole’s jets meant averaging observations across tens of thousands of years. There was no way to catch them in the act, moment by moment, and measure what they were actually doing right now. That has changed. For the first time, a team of scientists has measured the instantaneous power of jets blasting out from a black hole, and the number is staggering: the equivalent of 10,000 suns firing all their energy at once.

The study, led by Steve Prabu of the University of Oxford and published in Nature Astronomy, focused on Cygnus X-1, one of the most studied black hole systems in the sky. Located 7,200 light-years from Earth in the constellation Cygnus, the swan, this system has been known since the 1960s and holds a distinction that makes it ideal for this kind of measurement: the black hole is not alone. It orbits a blue supergiant star, and that companion changes everything.

Why Cygnus X-1 made this possible

In most black hole systems, measuring jet power in real time is practically impossible because there is no reliable reference point against which to track what the jets are doing from one moment to the next. Cygnus X-1 offers something rare: a powerful stellar wind from its companion star that continuously pushes against the jets, bending them in a measurable way.

Prabu and his team called these the dancing jets, a description that captures how the two streams of plasma are deflected in opposite directions by the wind blowing off the supergiant. By analyzing exactly how much the jets were bent, and combining those observations with detailed computer modeling, the researchers were able to calculate both the power and the speed of the jets with a precision that was not previously achievable.

The result for the speed was equally striking: approximately 355 million miles per hour, or 540 million kilometers per hour, which is roughly half the speed of light. The jets of Cygnus X-1 are moving at half the speed of light and carrying the energy output of ten thousand stars like our Sun.

Eighteen years of data, one system, one answer

The foundation of this measurement was not a single observation but 18 years of high-resolution radio imaging gathered by a global network of telescopes. That long baseline allowed the team to build a picture of the jets with enough detail to detect the subtle curvature introduced by the stellar wind and extract from it the physical parameters they were looking for.

One of the key findings that emerged from this analysis is that approximately 10 percent of all the energy released as matter falls toward the black hole is carried away by the jets rather than being radiated in other forms. That fraction has significant implications for understanding how black holes interact with their surroundings, because it means a substantial portion of their total energy output is channeled into these narrow, fast-moving streams of plasma that can travel enormous distances before dissipating.

Jets that shape the universe

The implications of this work extend well beyond Cygnus X-1. Jets from black holes are now understood to be one of the primary mechanisms through which black holes influence the galaxies around them. Through large-scale shocks and turbulence, these jets deposit energy into the interstellar and intergalactic medium, heating gas, suppressing star formation, and sculpting structures on scales that dwarf the black holes themselves.

Being able to measure jet power in real time, rather than inferring it from time-averaged estimates, opens a new observational window into these processes. Prabu has indicated that he plans to apply the same techniques to other black hole systems, which could make this kind of measurement a routine tool rather than a singular achievement tied to one exceptional source.

Cygnus X-1 has been a landmark object in high-energy astrophysics for more than half a century. This result adds another chapter to its history and demonstrates that even systems studied for decades can still yield genuinely new physics when approached with the right instruments, the right baseline of data, and the right question.

© 2026 SKYCR.ORG | Homer Dávila Gutiérrez, FRAS. All rights reserved. Total or partial reproduction prohibited without express authorization. Original source: Nature Astronomy DOI: 10.1038/s41550-026-02828-3