What are the rare “red elves” we see in the sky? (PICTURES)
An impressive phenomenon
The European Southern Observatory (ESO) in Chile recorded a rare phenomenon called “red sprites” in the night sky . The striking images reveal essentially large electrical discharges taking place at high altitude, above the clouds, between 50-90 kilometers, causing a variety of optical patterns that flicker across the night sky like orange-red lightning. However, they are a cold plasma phenomenon that lacks high temperatures and thus look more like flashes of light than lightning discharges.
The first images were captured in 1989 by the University of Minnesota and since then they have been photographed and videotaped thousands of times, from amateur photographers to the astronauts on the International Space Station. Their duration is longer than that of lightning which lasts only a few milliseconds and they have 1/10 the speed of light.
The ESO photo below might be your next wallpaper though. Red elves appear low on the horizon. For red elves to be recorded very specific conditions must exist. We should be able to clearly see a storm 150-500 km away, with positively charged lightning between ground and clouds. The sky should be dark without light pollution and the equipment should be sensitive to red light.
The green background is equally interesting, since it only appears in very dark skies where there is no light pollution. During the day, sunlight strips electrons from the nitrogen and oxygen of the Earth’s atmosphere, and at night these electrons rejoin atoms and molecules, giving that green light aura.
