APOD: 2026 September 11 – M83: The Southern Pinwheel

Today's Astronomy Picture of the Day, featured on September 11, 2026, showcases the spiral galaxy M83, popularly known as the Southern Pinwheel. This galaxy is located approximately twelve million light-years away, positioned at the southeastern edge of the long constellation Hydra. Its spiral arms, marked by dark dust lanes and blue star clusters, give it the distinctive name.

However, M83 is also called the Thousand-Ruby Galaxy due to the reddish star-forming regions scattered across its spiral arms. Despite being smaller than the Milky Way, it spans only 40,000 light-years. The galaxy is part of a group that includes the active galaxy Centaurus A. Intriguingly, the core of M83 emits strong x-ray radiation, indicating a significant concentration of neutron stars and black holes, remnants of a massive burst of star formation.

This image, captured through a ground-based telescope, also highlights foreground stars from the Milky Way and background galaxies that are much farther away. The picture was provided by Aldo Zanetti, with editorial guidance from Jerry Bonnell, Robert Nemiroff, Cecilia Chirenti, and Keighley Rockcliffe, and it is a service of the ASD at NASA/GSFC, NASA Science Activation, and Michigan Tech. U.