“月亮自身不会发光，月亮反射太阳的光线，月亮围绕着地球运动，总是展示相同的一面，因此无人知晓月亮的背面有何物”

The Moon does not shine by itself
The Moon reflects the light of the sun
The Moon ORBITS around the earth
Always showing the same side
So no one knows what is on the back of the moon