The colors represent the intensity of infrared radiation observed by the IRAS telescope. Blue areas represent regions of faint infrared emission, while green, yellow, orange and red areas show respectively more intense infrared emissions.
Brighter areas represent regions populated by either numerous or massive young stars.
Like our Galaxy, the Milky Way, Andromeda is a spiral galaxy. It is the nearest spiral galaxy similar to the Milky Way. IRAS observations of the galaxy represent the first extensive, high-sensitivity study of Andromeda in the infrared.