the.com/earthshine
The Moon glowing from Earth's reflected sunlight, a cosmic mirror showing us ourselves.
means Sunlight reflected off Earth that illuminates the dark side of the Moon, making the unlit crescent visible as a ghostly circle.
from From Earth + shine, but Leonardo da Vinci figured it out first in the 1500s, realizing the Moon wasn't mysteriously self-lit—we were the light source, bouncing sunlight back at ourselves across the void.
Da Vinci's insightHe understood it centuries before telescopes proved him right
Best viewing windowTwo to three days after new moon, when crescent angle is perfect
Climate trackerEarthshine brightness varies with cloud cover and reflects our planet's albedo
The physicsEarth's oceans and clouds reflect far more light than land does