A sensitive video camera at the summit of the Vosges in France captured these surprising fireworks over a distant horizon on June 26, 2020. Generated during intense thunderstorms, this one about 260 kilometers away, the flashes brief and mysterious became known as red sprites.
Transient light events are caused by a power failure at altitudes of 50 to 100 kilometers. This places them in the mesophere, the coldest layer of the atmosphere on planet Earth. The glow under the sprites comes from a more familiar lighting, under the storm clouds.
But on the right, the video images captured another summer appearance of the mesophere. The silver veins of light are polar mesospheric clouds. Also known as noctilucent or bright clouds at night, icy clouds always reflect sunlight when the sun is below the horizon.