W5 spans an area of sky equivalent to four Full Moons and is about 6,500 light-years away in the constellation Cassiopeia. This Spitzer picture was taken over a period of 24 hours. The color red shows heated dust that pervades the region's cavities. Green highlights the dense clouds, and white knotty areas are where the youngest of stars are forming. The blue dots are older stars in the star-forming cloud, as well as unrelated stars behind and in front of the cloud.