Black holes are known for swallowing everything around them, but some of them also fire out colossal jets of energy that can travel across space at near-light speed. These jets are so powerful that they can heat gas, stir turbulence, and even influence how galaxies evolve.
“Jets provide an important channel for kinetic feedback from accreting black holes into their environment, without which models of the formation of large-scale structure in the Universe fail to reproduce the observed properties of galaxies,” a new study notes.
However, despite decades of research, scientists have struggled to answer how powerful these jets are at any given moment. Until now, astronomers had to judge black hole jets by the giant scars they left behind in space over thousands of years. This was a bit like trying to understand an engine by studying old tire marks instead of watching the machine run in real time.
Now, an international team studying the famous black hole system Cygnus X-1 has achieved something unprecedented—they directly measured the instantaneous power of a black hole jet in action.
The results reveal jets carrying energy equal to around 10,000 suns while moving at nearly half the speed of light, offering one of the clearest views yet of how black holes pump energy back into the universe.
A black hole caught fighting stellar winds
The breakthrough came from an unusual strategy that relied on watching how the jets interacted with their surroundings rather than trying to measure the jets directly.
The study authors analyzed 18 years of high-resolution radio observations collected through a global telescope network. Their target was Cygnus X-1, one of the best-known black hole systems ever discovered and located about 7,200 light-years from Earth.
The system contains a black hole and a massive blue supergiant star orbiting each other. The star continuously sheds gas through strong stellar winds, and the black hole pulls in some of that material through its gravity.
“The impact of the wind can bend the jet away from the companion star,” the study authors said.
As the gas spirals inward, it becomes extremely hot and energetic. Some of this energy does not fall into the black hole. Instead, it gets launched outward as two narrow jets blasting in opposite directions.
Decoding the ‘dancing jets’
These jets were the key to the study. The researchers noticed that the powerful winds from the companion star were pushing and bending the jets as they traveled through space. According to the team, the jets appeared to “dance” under the force of the stellar wind.
“The overall jet trajectory is set by the relative strengths of the wind momentum flux and the momentum flux of the jet,” the study authors note.
By carefully measuring how much the jets bent and combining those observations with computer simulations, the scientists could calculate how much force the jets needed to resist the wind pressure.
This allowed them to estimate the jets’ true instantaneous power for the first time. The numbers were extraordinary. The jets were moving at roughly 355 million miles per hour (540 million kilometers per hour), nearly half the speed of light.
The calculations also showed that around 10 percent of the energy released as matter fell toward the black hole was redirected into the jets. This finding is important because it reveals how efficiently black holes can convert infalling matter into powerful outflows of energy.
Black holes may be shaping the cosmos more violently
The study changes how scientists think about black holes and their role in shaping the universe. Black holes are often portrayed as cosmic vacuum cleaners, but systems like Cygnus X-1 show they can also act like giant energy engines.
On much larger scales, similar jets from supermassive black holes can heat surrounding gas, generate shock waves, stir turbulence, and even affect star formation across entire galaxies.
For years, however, scientists lacked a reliable way to measure the real-time power of these jets. Previous methods relied on studying the large-scale aftermath left behind by jets over thousands of years.
As the study authors note, “The gold standard for measuring jet power to date relies on calorimetric methods.” However, those techniques could only provide long-term averages rather than instantaneous measurements.
By tracking how stellar winds bend the jets in Cygnus X-1, the new method effectively allows astronomers to measure jet power live.
Still, the work has limitations. The team examined only one binary system, so scientists do not yet know whether similar energy efficiencies occur across other black holes. The researchers now plan to apply the same technique to more systems, which could eventually reveal how black holes inject energy into the cosmos in real time.
The study is published in the journal Nature Astronomy.