The Southern Pinwheel Galaxy, also known as Messier 83 or NGC 5236, is a barred spiral galaxy located about 15 million light-years away in the constellation Hydra. It is one of the closest galaxies to Earth and is notable for its bright, well-defined spiral arms and a central bar structure. This galaxy spans approximately 40,000 light-years in diameter and contains a significant number of young, hot stars, which contribute to its vibrant blue color. Messier 83 is also home to various star-forming regions and has been studied extensively for insights into galaxy formation and evolution.