The green flash is a rare, brief optical event of green, yellow, and sometimes blue that colors the horizon, occurring at sunrise or sunset most often in the western U.S. Refraction and dispersion ...

In reality, a green rim is there at every sunset. It's just usually so thin, and so brief (a second or two), that our eyes ...

Blue flashes form in the same way as green flashes. However, the former is harder to spot because air molecules and aerosols scatter blue light, according to Spaceweather.com. When the atmosphere is ...