SpaceX Demo-2发射
2020 June 12 NGC 2359: Thor’s Helmet Image Credit & Copyright: Martin Pugh Explanation: NGC 2359 is a helmet-shaped cosmic cloud with wing-like appendages 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 inflates a region within the surrounding molecular cloud. Known as a Wolf-Rayet star, the central star is an extremely hot giant thought to be in a brief, pre-supernova stage of evolution. NGC 2359 is located about 15,000 light-years away in the constellation of the Great Overdog. The remarkably sharp image is a mixed cocktail of data from broadband and…