Powerful solar flare from Soho

Caption originale NASA: "Seen through the electromagnetic spectrum, the Sun briefly becomes over than 100 times brighter (in the X-rays wavelength) than normal. This is a so-called "Solar Flare" and, when it happens, energetic particles which are emitted from the Sun strike the Earth causing malfunctions in satellite communications or, in some specific areas, a very unusual (and yet very impressive) phoenomenon known as "Aurora Borealis".