The secondary light of the new moon
Codex Leicester, Sheet 2A, folio 2r |
Curious about every aspect of nature, Leonardo is credited with the first correct explanation of why the crescent Moon in the twilight sky shows a gentle glow across its unilluminated parts. He arrived at this explanation through a remarkable sequence of ideas. Using simple arguments about the reflectivity of the Earth's and the Moon's surfaces and the continually
changing relative positions of the Earth, Moon and Sun, Leonardo perceptively deduced that sunlight can reflect from the Earth and illuminate the unlit portion of the crescent Moon. |
