NGC 2359: Thor s Helmet . ... Credit Copyright: Bob and Janice Fera ( Fera Photography ) Explanation: This helmet-shaped cosmic cloud with wing-like appendages is popularly called Thor's Helmet. Heroically sized even for a Norse god , Thor's Helmet is about 30 light-years across. In fact, the helmet is more like an interstellar bubble , blown as a fast wind from the bright, massive star near the bubble's center sweeps through a surrounding molecular cloud. ... NASA Official: Jay Norris. ...