... 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. ... Probably not, but of all the animals on Earth, the tardigrade might be the best candidate. ... Two impressive comets will both reach their peak brightness during the next two weeks. ... One of the natural wonders of planet Earth, the Grand Canyon in the American southwest stretches across this early evening skyscape. ...