The shadow on the moon, as it appears in the changing phases of the moon, is not cast by the earth.
This is how it is mostly explained intuitively - and incorrectly. When the Earth's shadow hits the moon, we speak of a lunar eclipse, and it doesn't happen too often.
The shadow of the moon phases comes from the moon itself.
We see the unlit part of the moon. As the moon orbits around the earth, the appearance of the moon and shadow changes.
We see him fully lit at full moon, his unlit part at new moon, and in between - at half moon - we see the unlit and illuminated part from the side at the same time.
Just like watching someone on the beach standing in the sun. Go around it. Once you see its unlit part (new moon), then its fully illuminated front (full moon). And in between from the sides (crescent).
Terms: penumbra, umbra, moon phase, full moon, new moon, crescent moon, waxing moon, waning moon, ecliptic, partial lunar eclipse, total lunar eclipse, albedo
Background
The moon is illuminated by the sun as it moves around the earth. It does not shine itself; exactly half of the moon is always lit - the side illuminated by the sun. Depending on how the moon and the sun are in relation to each other, we see different amounts of this illuminated half.
The same phases of the moon can be seen all over the world. All humans see the same moon phase, but the orientation of the moon to the horizon changes with its position on Earth. In the central northern latitudes, the moon is “upright”, as we are used to: Round side to the right - as the moon rises, to the left - as the moon goes down. In middle southern latitudes it is “upside down”, the waxing moon points there with the round side to the left.
What happens in a lunar eclipse?
Only during the lunar eclipse does a shadow appear on the moon that is caused by the earth: the earth stands between the moon and the sun so that the earth casts its shadow on the moon.
A lunar eclipse is an astronomical event that occurs when the moon wanders through the shadow space of the earth. However, this cannot happen every month. Since the earth's orbit (ecliptic) and the moon's orbit are slightly inclined towards each other, the moon usually passes just above or below the earth's shadow.
