The Seagull and the Duck

Explanation: Seen as a seagull and a duck, these nebulae are not the only cosmic clouds to evoke images of flight. But both are winging their way across this broad celestial landscape, spanning almost 7 degrees across planet Earth's night sky toward the constellation Canis Major . The expansive Seagull (upper left) is itself composed of two major cataloged emission nebulae . Brighter NGC 2327 forms the head with the more diffuse IC 2177 as the wings and body. Impressively, the Seagull's wingspan would correspond to about 250 light-years at an estimated distance of 3,800 light-years. At the lower right, the Duck appears much more compact and would span only about 50 light-years given its 15,000 light-year distance estimate. Blown by energetic winds from an extremely massive, hot star near its center, the Duck nebula is cataloged as NGC 2359 . Of course, the Duck's thick body and winged appendages also lend it a more dramatic popular moniker -- Thor's Helmet .