Super Mario Galaxy - Gateway to the Starry Sky

This is where your journey begins. The most important fact is that The Gateway Galaxy is found here. This Galaxy serves as a tutorial to the game, and introduces you to the world of Super Mario Galaxy.

Once completed it will remained unlocked till much later in the game. Once Unlocked; just beside the Gateway is a hungry luma which will provide an additional level called Boo's Boneyard Galaxy.