For all those who’ve been to seen the Avengers movie in the cinemas, here’s a geeky little tribute — This is Thor’s Helmet!
Around 15000 light years away, and spanning 30 light years in size, Thor’s Helmet (or NGC 2359 as it’s more conservatively known) is an emission nebula caused by a Wolf-Rayet star. A huge furious beast of a star, burning so brightly it’s practically tearing itself apart. What you’re seeing in Thor’s Helmet is a huge stellar wind bubble blown by the star itself, seen as the bubbly blue central part in this image (emission from oxygen). That wind bubble (and the furious host star within) is blasting its way through a patch of dense interstellar cloud. As it ploughs it’s way through, it creates a huge bow shock (exactly like the bow waves boats leave on the ocean) which you can see as the helmet’s wings in this image, where the red colour is coming from hydrogen.
Really, if that isn’t staggeringly melodramatic enough for a thunder god, I don’t know what is!
Image credit: Star Shadows Remote Observatory & PROMPT / UNC (Steve Mazlin, Jack Harvey, Rick Gilbert, and Daniel Verschatse)