Those looking at the night sky this week may spot a faint, ghostly glow illuminating the entire moon.
The phenomenon, known as “Da Vinci glow,” is named after artist and inventor Leonardo da Vinci. In addition to his artistic endeavors, the Renaissance innovator set out to solve the mystery of what was once known as the “Earth’s brilliance,” According to NASA.
A celestial event is only visible when there is a crescent moon on the horizon at sunrise or sunset. During this phenomenon, the crescent part of the moon shines brightly, and the dark side of the moon is visible as clouds. The glow is not because the moon is illuminating itself. NASA says it was created by the planet Earth, whose light can illuminate the night sky 50 times brighter than that of a full moon.
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How did Leonardo da Vinci discover the cause of the glow?
In the 16th century, NASA said, da Vinci set out to solve the mystery of this ghostly luminosity. The drawing he made to show the phenomenon is found in his notebooks and celebrated in the “Codex Leicester,” a collection of da Vinci’s scientific writings.
Da Vinci, like his contemporaries, operated with an incomplete understanding of the solar system. According to NASA, the theory that the sun was at the center of the solar system will not be published for another two decades, and of course no one has traveled to the moon yet. As a result, there was not much knowledge about the Sun’s proximity to the Earth.
According to NASA, there is a page in “Codex Leicester” titled “From the Moon: No Solid Object Is Lighter Than Air”. In the entry, da Vinci notes several ideas, including the theory that the moon has an atmosphere and oceans. He was right on the first point, though NASA missions have debunked the latter. Da Vinci also wrote that the moon acted as a reflector of light.
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Using this information, he proposed a hypothesis: the ghostly glow of Earth’s rays was caused by sunlight bouncing off Earth’s oceans and striking the Moon.
According to NASA, da Vinci was right about the phenomenon’s broad strokes. Later research found that it wasn’t light reflecting off Earth’s oceans that caused the glow. Instead, the primary source was the light reflecting off the clouds.
How can I see the Da Vinci glow?
According to Live Science, it is only possible to see the glow when the thin crescent moon is visible near the horizon during the first or last few days of the moon’s orbit. This happens this week, making the morning of Thursday, May 17, before sunrise, a good time to try and see this phenomenon.
The best days to see it after sunset are next week on Sunday, May 21; Monday, May 22, and Tuesday, May 23, Live Science said. Try looking at the sky in the hour after sunset.
Earthshine is generally brightest between April and June, NASA said.
Flare detection requires no special equipment. In fact, it is best seen with the naked eye. A small telescope or a pair of binoculars can help but are not necessary.