Depending on what you name your save file, the name inputted will act as a seed that determines the position of the twinkling white stars in the night sky, while the blue stars and larger red planet remain in the same position. Since there is a character limit of 8 characters for a name, the number of possible variations is estimated to be somewhere under 5.3 billion, the key word being "under" as this cosmetic feature does not utilize all 127 characters available, so the actual number is bound to be lower.