Planets are the main construct of Cosmic Encounter. Each player starts with his or her own system of five planets of his or her player color, with four of his or her ships on each planet. The goal of the game is to land ships on and gain colonies on five planets in other players' systems.
In the current edition of Cosmic Encounter, each planet is its own mini-board about 2 3/4 inches in diameter, with each player receiving five mini-board planets of his or her color during setup. This allows players to arrange them however they like, and makes it possible for cards and powers to manipulate and interact with their placement. In previous editions, all five of a player's planets were printed on one board, with each player getting one board each.