Pinwheel Galaxy

M101 in Ursa Major is a grand-design face-on spiral galaxy about 20.9 million light-years away, spanning roughly 170,000 light-years — significantly larger than the Milky Way. Its beautifully symmetrical arms are laced with pink star-forming HII regions and dark dust lanes, making it one of the most photogenic spirals in the northern sky. The asymmetry of its arms is thought to result from past tidal interactions with the smaller companion galaxy NGC 5474, visible to the south. Discovered by Pierre Mechain in 1781, it has since hosted several recorded supernovae, the most recent of which — SN 2023ixf — was discovered in May 2023.