A fire hose blasts into a snowdrift. The water doesn't just shove the snow aside — at the point of impact, spray, steam, and a roar are born. That's roughly how jets behave: narrow streams of matter shooting out from around a black hole at enormous speeds. When such a stream crashes into an interstellar gas cloud, it doesn't punch straight through; instead, it creates a shock wave, compresses the gas, and makes it glow.
This is exactly what astronomers have now seen for the first time in the system SS 433 — a microquasar that ejects jets tens of light-years long. Using the 45-meter radio telescope at Nobeyama, they found dense clumps of carbon monoxide (CO) precisely where SS 433's jets flare in X-rays.
This is direct evidence: the jet isn't just glowing on its own; it's slamming into surrounding matter.
The X-ray glow doesn't come from hot gas but from electrons accelerated in a magnetic field. The jet's impact on the molecular cloud stirs up turbulence — chaotic swirls that, like a dynamo, amplify the magnetic field. In this field, electrons spiral and emit X-rays. The same mechanism operates in the much larger jets of distant galaxies, but here it's confirmed for the first time for a microquasar — an object the size of a star system.
So the impact of a cosmic jet on a gas cloud turns into an X-ray flare, like the spray and steam from a hose hitting a snowdrift.
SS 433's jets travel at about a quarter of the speed of light—75,000 km/s. At that speed, you could fly from Earth to the Moon in 5 seconds.
In Vernor Vinge's novel A Fire Upon the Deep, the jets of relativistic objects serve as natural boundaries dividing zones of intelligence in the galaxy — much like SS 433's shock waves separate the jet's hot gas from cold clouds.