Why do oxygen atoms emit different colors at different altitudes during an aurora display?
An aurora taken from the International Space Station, as the ISS orbited earth at about the same altitude as the aurora. From orbit, Pettit reported that flickering auroras appeared to crawl around like giant, green amoebas. Photo courtesy of Don Pettit, NASA. During an aurora display, different atoms glow different colors (depending on their electrical state-ionized or neutral-and on the incoming particle’s energy) to form vibrant, many-hued rings over Earth. Bombarded nitrogen ions shine blue and neutral nitrogen shines red. Oxygen atoms hit by incoming charged particles 200 miles high glow red, the rarest aurora color. At about 60 miles, glowing oxygen produces the most common color: a brilliant yellow-green. An atom glows because the charged particle that hit it transferred kinetic energy to the atom. The atom often dumps the extra energy by emitting light and returns to its normal energy state. It glows like a neon atom inside a neon sign. The red and green oxygen emissions “…co
