The moon and its "Earthglow" arrive in the sky this week. Also known as the "Glow of Vinci", in homage to the Italian genius Leonardo da Vinci, who was the first to unravel (part of) the mystery, 500 years ago, this celestial phenomenon does not occur than when the moon is a thin crescent in the sky, reports Ouest-France. It can be observed during the first and last day of the moon's orbit around the Earth. Although it is also visible in the morning, it is in the evening that it is easiest to spot it.
According to NASA, this phenomenon appears whenever a crescent moon is on the horizon at sunset. This ashy glow, also called "Da Vinci Glow" or "earthshine", colors the dark part of the Moon when it only shows a crescent. The outline of the Moon is thus drawn, whereas it should be largely invisible. In reality, it is simply sunlight reflected first by the Earth and then on the lunar surface.
For thousands of years people have marveled at the beauty of the glow on the surface of the crescent moon. In the 16th century, Leonardo da Vinci solved the mystery. He determined that sunlight reflected from the earth was the source of the image. But the Italian artist got a few things wrong, including that the earth's oceans were the main source of earth's light. In fact, it is the clouds. The best time to see this phenomenon this year would be in the days before and after the May 19 new moon. According to NASA, during the months of April and May, reflected light is about 10% brighter than average.
