This photograph of Andromeda was taken in infrared light. Astronomers use infrared images of galaxies to find regions where new stars are forming. The dusty clouds in which stars tend to form act like smoke-screens and hide visible light. Infrared light easily penetrates the dust to let us know what is hiding within the cloud.
IRAS (Infrared Astronomical Satellite) detected strong infrared emission (yellow, orange, and red) in both the center of Andromeda and in the ringlike structure. The ring is actually the galaxyΓÇÖs spiral arms; because we see Andromeda from a tilted view, the arms appear to form a circle.
AndromedaΓÇÖs infrared emission comes from two sources: the warm dust that has been heated by new
