Turning The Sky Black
Mark de Silva interviewed Guy Deutscher about his new book Through the Language Glass. De Silva ask what is "the best explanation for Homer’s describing honey as green, oxen as wine-colored, and iron as violet?" He follows up by asking why "the natives of Murray Island call the sky black." Deutscher's anwer:
Well, as for the first question, I can’t explain it better than William Ewart Gladstone did one hundred and fifty years ago: “Colours were for Homer not facts but images: his words describing them are figurative words, borrowed from natural objects. There was no fixed terminology of colour; and it lay with the genius of each true poet to choose a vocabulary for himself.” For Homer, the word that ended up meaning "green" meant something like "fresh" or "pale," and could be applied with perfect sense to fresh and pale looking things of both green and yellow hue.
The distinction in hue between yellow and green was not one that seemed very important in his day. Similarly, in many cultures "blue" is just considered a particular shade of black, and finding a particular name for this particular shade is not a very pressing matter, especially as blue material objects (as opposed to the vast nothingness of sky or even the sea) are extremely rare in nature. So it makes perfect sense, if some nagging anthropologist comes to question you about the color of the sky, to use the nearest color on your palette, and say "black."