The Pinwheel Galaxy in the constellation Ursa Major (the Greater Bear) is a “grand design” spiral, meaning that it has well-defined spiral arms and dust lanes that extend all the way around the body of the galaxy. It was discovered in 1781 by astronomer Pierre Méchain, and included as object number 101 in Charles Messier’s list of celestial objects.

A spiral galaxy with about 1 trillion stars located in the Ursa Major (also called the Greater Bear) constellation is the Pinwheel Galaxy. The galaxy has well-defined spiral arms and dust lanes extending all the way around the body of the galaxy. The Pinwheel was discovered in 1781 by astronomer Pierre Méchain and was communicated to Charles Messier who verified its position. He has described it as a "nebula without star, very obscure and pretty large, 6' to 7' in diameter, between the left hand of Bootes and the tail of the Great Bear." The galaxy is about 70% larger than the Milky Way Galaxy or over twice its diameter.