After more than 50 years of searching, astrophysicists at Northwestern University in Illinois, USA, have identified evidence of a powerful wind emanating from Sagittarius A*, the supermassive black hole at the center of our Milky Way galaxy. The discovery—described by the US-based researchers as a major milestone—confirms a long-standing theoretical prediction: as black holes consume matter, they are expected to generate strong winds or particle jets.
Even small amounts of gas falling into a black hole should release enough energy to expel surrounding material outward. Yet until now, no one had successfully detected such a wind from Sagittarius A*. According to the researchers, this is largely because the black hole is currently in a relatively quiet phase of its life—and also because it lies deep within dense clouds of interstellar gas and dust, making observations exceptionally challenging.
The study, published in The Astrophysical Journal Letters, provides the most detailed picture to date of how Sagittarius A* interacts with its immediate environment. Using five years of extensive radio observations from the ALMA telescopes in Chile, the team created the highest-resolution image ever obtained of cold molecular gas surrounding Sagittarius A*.
The imaged region lies extremely close to the black hole—just one parsec (about three light-years) away. To isolate faint signals from the surrounding gas, scientists applied a specialized calibration technique to subtract the bright radio emission directly from the black hole itself. The resulting image is 100 times more detailed and 80 times sharper than previous maps of the area—revealing structures previously invisible to astronomers.
In particular, the analysis uncovered a massive conical cavity—nearly one parsec long with an opening angle of about 45 degrees—that shows no trace of cold molecular gas. Researchers say only a hot, energetic wind blowing directly from the black hole could have carved out such a feature. Crucially, the cone points precisely toward Sagittarius A*, marked by a white dot at the center of the image. Orange areas show ALMA radio data mapping the location of cold gas; blue areas display X-ray data from NASA’s Chandra X-ray Observatory.
While stars also produce stellar winds, the team notes these are far too weak to excavate a cavity of this scale—even the combined output of all nearby stars falls short. To verify their findings, the scientists compared their data with observations from the James Webb Space Telescope and other observatories—further supporting the conclusion that the cavity was shaped by the black hole’s own wind.