Messier 101 is a spiral galaxy that looks like a pinwheel. It was discovered by the 18th-century French astronomer Pierre Méchain. /NASA, ESA, CFHT, NOAO

Messier 101 is a spiral galaxy that resembles a pinwheel. The galaxy's arms are made up of stars and gas, creating a swirling appearance. It is located 25 million light-years away in the direction of the Ursa Major constellation. The diameter of the galaxy is 170,000 light-years. It was first discovered in the late 18th century by French astronomer Pierre Méchain. His friend Charles Messier later included it in his catalog of celestial objects, giving it the name Messier 101.