- Spiral arm (Wikipedia)
Spiral arms are a defining feature of spiral galaxies. They manifest as spiral-shaped regions of enhanced brightness within the galactic disc. Typically, spiral galaxies exhibit two or more spiral arms. The collective configuration of these arms is referred to as the spiral pattern or spiral structure of the galaxy.
- Big Stone Lake (Wikipedia)
Big Stone Lake (Dakota: Íŋyaŋ Tháŋka Bdé) is a long, narrow freshwater lake and reservoir on the border between western Minnesota and northeastern South Dakota in the United States.