Explanation
Green flashes are enhanced by mirage, which increase the density gradient in the atmosphere and therefore, increase refraction. A green flash is more likely to be seen in clear air, when more of the light from the setting sun reaches the observer without being scattered. One might expect to see a blue flash, but the blue is preferentially scattered out of the line of sight, and remaining light ends up looking green.
With slight magnification a green rim on the top of the solar disk may be seen on most clear-day sunsets, although the flash or ray effects require a stronger layering of the atmosphere and a mirage, which serves to magnify the green from a fraction of a second to a couple of seconds.
Read more about this topic: Green Flash
Famous quotes containing the word explanation:
“To develop an empiricist account of science is to depict it as involving a search for truth only about the empirical world, about what is actual and observable.... It must involve throughout a resolute rejection of the demand for an explanation of the regularities in the observable course of nature, by means of truths concerning a reality beyond what is actual and observable, as a demand which plays no role in the scientific enterprise.”
—Bas Van Fraassen (b. 1941)
“How strange a scene is this in which we are such shifting figures, pictures, shadows. The mystery of our existence—I have no faith in any attempted explanation of it. It is all a dark, unfathomed profound.”
—Rutherford Birchard Hayes (1822–1893)
“The explanation of the propensity of the English people to portrait painting is to be found in their relish for a Fact. Let a man do the grandest things, fight the greatest battles, or be distinguished by the most brilliant personal heroism, yet the English people would prefer his portrait to a painting of the great deed. The likeness they can judge of; his existence is a Fact. But the truth of the picture of his deeds they cannot judge of, for they have no imagination.”
—Benjamin Haydon (1786–1846)