Blue skies?

Sword Beach, Ouistreham, Normandy. Great day for a landing! Why is the sky blue? I asked a couple of years ago. At the end of the day the answer really is “because we say it’s blue”. In 2012 Radiolab had a fascinating broadcast about color which explores this as well as other questions. They repeated the show in August this year. You can listen to the program, or if you prefer follow the transcript, at this link. William Ewart Gladstone loved Homer, and would read The Iliad and The Odyssey over and over. In Greek of course: nineteenth-century Prime Ministers would of course know Greek. He wrote a massive study of Homer’s work in the course of which he pointed out the peculiarity of Homer’s use of color descriptors. He noticed that while black and white were mentioned hundreds of times, red was rarely mentioned, while blue did not figure at all. His count: black about one hundred and seventy; white about a hundred; red c. thirteen; yellow and green less than ten; blue —zero. It’s not…