The Green Flash of the Sun
Sometimes, from certain places, the light from the sun can briefly appear green. NASA's Astronomy Picture of the Day explains,
Just as the setting Sun disappears completely from view, a last glimmer appears startlingly green. The effect is typically visible only from locations with a low, distant horizon, and lasts just a few seconds. A green flash is also visible for a rising Sun, but takes better timing to spot. A dramatic green flash was caught in the above photograph in 1992 from Finland. The Sun itself does not turn partly green, the effect is caused by layers of the Earth's atmosphere acting like a prism.