 Avempace’s commentary presents his own theory of the Milky Way. Aristotle explained it as the ignition of the fiery exhalation of some stars which were large, numerous and close together. The ignition takes place in the upper part of the atmosphere, in the region of the world which is continuous with the heavenly motions (Meteo. 346b 11–12). The version transmitted by Ibn al-Bitriq diverges and considers the Milky Way to be a phenomenon exclusively of the heavenly spheres, not of the upper part of the atmosphere. The light of those stars makes a visible patch because they are so close.