EDIT Earthshine on crescent moon
Sometimes when there is a crescent moon shortly after sunset, you can see the bright crescent of the moon but you can also see the rest of the moon as a dark disc. Why can I see the dark disc of the moon? Shouldn’t it be pitch dark like space?
That pale glow on the unlit part of a crescent moon is light reflected from Earth. It’s called “earthshine.” Bright moonlight can illuminate an earthly landscape on nights when the moon is full. Likewise, whenever we see a crescent moon, a nearly full Earth appears in the moon’s night sky – and illuminates the lunar landscape. Next time you see a crescent moon, think about the fact that the sun is just below your western horizon.
And when you’ve got that sense of the moon and sun in space, expand your thinking – to include the Earth under your feet. You might get a sense of the sun, shining on Earth’s day side – and see the glow on the unlit portion of the moon for what it really is – sunlight reflected from Earth.
More resources on “space”…