World 1 (Super Mario Galaxy 2)

World 1: The Great Space Journey Begins is the first world featured in Super Mario Galaxy 2. It is located very high in the atmosphere of the Mushroom World, which actually can be seen from the map. It holds seven galaxies, the last of which, Bowser Jr.'s Fiery Flotilla, features the first encounter with Bowser Jr., who attacks using Gobblegut.

Galaxies

 * Sky Station Galaxy
 * Yoshi Star Galaxy
 * Spin-Dig Galaxy
 * Fluffy Bluff Galaxy
 * Flip-Swap Galaxy (Hungry Luma)
 * Rightside Down Galaxy
 * Bowser Jr.'s Fiery Flotilla

Music

 * The music that plays on the World 1 map is initially the same as the music for World 2. However, after Mario has collected at least 120 Power Stars, the music becomes a quiet, slowed-down rendition of the theme from the Good Egg Galaxy.
 * The location that Rosalina flies the Comet Observatory into at the end of Super Mario Galaxy looks a lot like World 1 of Super Mario Galaxy 2, as it is a circular blue area with what appears to be a few planets towards the middle of it.