Green flash sun is an optical phenomenon that takes place just before the sunset or the sunrise. Whenever it occurs, a green spot becomes visible for a fraction of seconds. A green rim is produced on the top of the solar disk. When the sun slowly slides down on a grand ocean horizon and as the sun shrinks, for a matter of second, an intense emerald green flash can be observed.
This exceptional marvel can be observed from any altitude. Green flash sunsets are usually seen at an unhindered horizon that includes ocean, clouds and mountain tops.
A Green flash sunrise and sunset are enhanced when light rays bent and produce distorted image of the Sun, which is technically known as mirage. When the sun sets or raises the light emitted travel through the Earth’s atmosphere acts as a prism, hence separating the light into a spectrum.
You are most likely to observe this phenomenon in clear air. The coloration of the Sun can vary from blue to violet, which mostly depends on the concentration of pollutants. The green rim is impossible to see with the naked eye.
In some cultures, green flash in sky is considered good luck while in some it is another menacing omen. Hawaii and the Caribbean are the best locations to spot a green flash.