Dark Moon Night PIN Lock

The dark night moon - PIN Screen Lock.
Since ancient times people have tried to describe and explain the movement of the moon using the accurate theory of everything. Moon - the closest human companion in our journey in space and the only celestial body that we visited. However, despite its relative proximity to us and apparent simplicity, our satellite continues to hide many interesting facts. This application contains a collection of pictures of 5 months that will decorate your lock screen.
Between the moon's rotation around its own axis and its revolution around the Earth there is a difference: the moon revolves around the Earth with variable angular velocity due to the eccentricity of the lunar orbit (Kepler's second law) - near perigee moves faster near its peak - slowly. The rotation of the satellite around its axis even. This allows you to see from Earth western and eastern edge of the back side of the moon. This phenomenon is called optical libration for longitude.
Moon is not glowing body, like all the world. Watching it is only because it reflects the light of the sun. The moon is always illuminated by the sun on one side only, but the earth observer at different times sees half illuminated from different angles. The moon changes its visible form, and these changes are called phases. The phases depend on the relative positions of the Earth, moon and sun.