The black hole MAXI J1810-222 behaves like a giant vacuum cleaner with a reverse valve: it pulls in matter, but some of it gets spat back out into space. This "backflow"—a stellar wind — had been spotted by astronomers before, but only as a blurry smudge in X-rays. Now, the RGS spectrometer on the XMM-Newton satellite came to the rescue. It can split X-ray light by wavelength, just as a prism splits sunlight into a rainbow. And in that rainbow, sharp dark lines appeared — the telltale signs of light absorbed by iron atoms in the rushing wind.

The wind's speed turned out to be enormous — about 30,000 kilometers per second. That's a tenth of the speed of light. For comparison, the fastest spacecraft ever built by humanity, the Parker probe, travels 200 times slower. Such speed can't arise from mere gas heating — something extra must be accelerating it. Most likely, magnetic fields twisted around the black hole act like a coiled spring that straightens out and flings matter outward.

The new observations confirmed that the wind is real, not a measurement error. But now it looks less like a narrow jet and more like a broad outflow with fuzzy edges. That means matter isn't being carried away in a single blob but as a whole cloud with varying speeds and temperatures. The researchers hope that the upcoming Japanese X-ray telescope XRISM, with its ultra-sensitive detector Resolve, will reveal this wind in even greater detail, and then it will become clear how black holes pump mass and energy into their galaxies.