Astronomy Picture of the Day Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer. 2013 September 24 The Local Fluff Illustration Credit: NASA, Goddard, Adler, U. Chicago, Wesleyan Explanation: The stars are not alone. In the disk of our Milky Way Galaxy about 10 percent of visib..