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. 2002 November 29 Open Star Clusters M35 and NGC 2158 Credit & Copyright: N. A. Sharp (NOAO), AURA, NSF Explanation: Open clusters of stars can be near or far, young or old, and diffuse or compact. Open clusters may contain from 100 to 10,000 stars, all of which formed at nearly the same time. Bright blue stars frequently distinguish younger open clusters. M35, pictured above on the upper...