Solar flare, SDO imagery. The flare is seen as the bright loop, in three successively closer views. Flares are eruptions of particles and energy from the Sun's surface. They form around sunspot groups (bright spots), where magnetic field lines from the surface of the Sun interact with its atmosphere, the corona. The flares are produced as the magnetic field releases its energy. This was an M5.5 class flare, a powerful event, that took place on 4th September 2017. The Solar Dynamics Observatory (SDO) is a satellite that has been studying the Sun since 2010. This image was captured at a wavelength of 131 Angstroms.