Webb Captures Unprecedented Details Inside Milky Way's Largest Star Nursery

by Aaron Leong — Thursday, September 25, 2025, 10:23 AM EDT

The ever-busy James Webb Space Telescope (JWST) recently turned its gaze toward the core of our galaxy and revealed unprecedented details of the largest and most active stellar nursery nestled within. Webb's target, the massive Sagittarius B2 (Sgr B2) molecular cloud, is a cauldron of star formation located a mere few hundred light-years from the supermassive black hole at the galactic center. The new images, which are results of research by astronomers from University of Florida as well as an international team, gives us a more vivid view into the often-hidden process of how stars are born.

Often described as the most active birthplace of stars in our galaxy, Sgr B2 (despite containing only 10% of the galactic center's gas, is responsible for half of its star-forming activity) has long been a subject of fascination for astronomers. However, the gas and dust density in that region has obscured much of its activity from traditional telescopes.

nircam side — *Stars, gas and cosmic dust in the Sg B2 molecular cloud glow in near-infrared light, captured by Webb’s NIRCam*

Thanks to Webb's Near-Infrared Camera (NIRCam) and Mid-Infrared Instrument (MIRI) though, the captured images are truly breathtaking and a goldmine for scientists. NIRCam was able to capture a field of colorful stars and glowing gas clouds, showing areas where new stars are actively forming, while also highlighting the contrast between the stars and the material that forms them. On the other hand, MIRI's view shows the warm, glowing cosmic dust heated by these newborn stars. Nazar Budaiev, one of the researchers from UF, remarked that JWST "is not just giving us a clearer picture of our own galaxy, but also helping us understand how galaxies grew and evolved across cosmic time.”

miri side2 — *The same shot as the NIRCAM's view, but this time by MIRI*

Somewhat ironically, some of the most captivating parts of the images are actually the areas that remain completely dark; these aren't empty voids, but rather regions where the concentration of gas and dust is so dense that even Webb's infrared vision cannot penetrate. These dark areas are, in fact, the most densely packed regions of stellar material, serving as cocoons for future stars that are still too young to shine.

Astronomers ultimately hope to uncover the reason behind this disproportionate level of stellar productivity between Sagittarius B2 and the rest of the region.

Photo credits: NASA, ESA, CSA, STScI, Adam Ginsburg (UF), Nazar Budaiev (UF), Taehwa Yoo (UF)