Starship Mario

Starship Mario is a planet in Super Mario Galaxy 2 used to travel across the universe. It is in the shape of Mario's head. Although notably smaller than the previous games' hub areas, it serves as the hub of the game and has, more or less, replaced the Comet Observatory from the first game. Other than its smaller size, another difference from the Observatory is that it also has changing backgrounds, the appearance of which depend on the world that it is currently in.

While on the Starship, Mario is capable of exploring and interacting with various non-playable characters, including Lubba, the Toad Brigade, and the Assist Luma. Other characters, like Hungry Lumas and Bob-omb Buddies have been seen in official art of the ship, suggesting that they will also inhabit the planetoid. Much like Delfino Plaza from Super Mario Sunshine, Mario can also ride Yoshi here, and the egg which contains him is located on the "nose" of the starship.

The starship's main purpose, though, is to allow Mario to travel between and select galaxies to visit. To leave the starship and go to the world map, one must step up to a ship's wheel near the top, in front of which is a small weight-activated button. When pressed, the button sends the player to the world map, from where he/she can select galaxies.

Trivia

 * The picture of Starship Mario entering World 2 (pictured below) may be beta as the blue info bar showing the galaxies in that world has a picture of the Rightside Down Galaxy's icon, though the Rightside Down Galaxy is in World 1.