NASA recently celebrated Halloween on Instagram and Facebook with a photo of the sun looking like a cosmic jack-o’-lantern. NASA’s Solar Dynamics Observatory took this ultraviolet image in October 2014, showing active areas on the Sun.
The active areas in this image appear sharper because those are areas that emit more light and energy. They are markers of an extraordinary and complex set of magnetic fields floating in the sun’s atmosphere, the corona.
You can find more images as well as download the high-resolution variants of this image on NASA.