The green flash is an optical phenomenon that can be seen shortly after sunset or before sunrise, when the sun is almost entirely below the horizon and the upper edge is still visible.
It appears as a green spot above the sun's upper limb, usually lasting for no more than two seconds.
Rarely, the green flash can resemble a green ray shooting up from the sunset or sunrise point.
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The green flash is an optical phenomenon that you can see shortly after sunset or before sunrise. It happens when the sun is almost entirely below the horizon, with the barest edge of the sun – the upper edge – still visible. For a second or two, that upper rim of the sun will appear green in color.
How can I see a green flash? | Earth | EarthSky
Green flash occurs because the atmosphere causes the light from the Sun to separate, or refract, into different frequencies. Green flashes are enhanced by mirages, which increase refraction. A green …
Green flash - Wikipedia