>> we're obviously looking at the earth's dark side
> We are not. Why would we?
Yes we are.
Because the earth is in between the sun (faraway) and the moon (where we are) and very close to the line between the sun and us (because they're close by in the image -- it's not like the sun is in front and the earth is 90° above us which would half-illuminate it, or 180° behind us which would entirely illuminate it).
If you turn on a lamp in a room, and hold an object between you and the lamp, obviously you're looking at the side of the object that is in shade. The illuminated side faces the lamp, which is opposite you.
> We are not. Why would we?
Yes we are.
Because the earth is in between the sun (faraway) and the moon (where we are) and very close to the line between the sun and us (because they're close by in the image -- it's not like the sun is in front and the earth is 90° above us which would half-illuminate it, or 180° behind us which would entirely illuminate it).
If you turn on a lamp in a room, and hold an object between you and the lamp, obviously you're looking at the side of the object that is in shade. The illuminated side faces the lamp, which is opposite you.