Within the virtual galaxy, the player can explore some 400 billion star systems complete with planets and moons that rotate and orbit in real time, reflecting dynamic day-night cycles. Around 150,000 of the game's star systems are taken from real astronomical data, while a few partially fictional planetary systems, which were created in "Frontier" and "First Encounters" before a significant number of exoplanets were discovered, are carried over. For example, none of the gas giants of the Fomalhaut system correspond with the detected properties of Fomalhaut b. A handful of entirely fictional systems named in the original "Elite", and also featured in later games, are included (e.g. the original starting system Lave). The remainder are procedurally generated according to scientific models. Players can dock their ships at space stations and outposts located throughout the galaxy in star systems to trade goods, purchase new spacecraft, re-arm their ship, effect repairs and do missions from Mission Boards. Players may also find lost cargo or encounter other ships while in flight by investigating Unidentified Signal Sources.