M101, the Pinwheel GalaxyM101 sits roughly 21 million light years away in Ursa Major, and even at that distance the structure is remarkable. The spiral arms are clearly defined, threaded with blue star forming regions that contrast against the warm golden core. It's a face on galaxy, which means we're looking straight down into it, and that orientation reveals detail that would be lost at any other angle. What I find fascinating about this image is the tidal stream curving