This is because they are at the top and bottom of each because of the earth's tilted axis it can happen that the light doesn't go there for a very long time untill the earth has turned again then there's a long period of daylight again.
Why is one side of the moon called the "dark side of the moon" ? A. Earth is in The moon's Shadow B. the moon both rotates on its axis and revolves around Earth every 28 days. C. The moon is in Earth's Shadow.
