On July 24, 2016, NASA's Interface Region Imaging Spectrograph, or IRIS, captured a mid-level solar flare: a sudden flash of bright light on the solar limb – the horizon of the sun – as seen at the beginning of this video. Solar flares are powerful explosions of radiation. During flares, a large amount of magnetic energy is released, heating the sun's atmosphere and releasing energized particles out into space. Observing flares such as this helps the IRIS mission study how solar material and energy move throughout the sun's lower atmosphere, so we can better understand what drives the constant changes we can see on our sun.