Galaxy

A galaxy is an enormous system consisting of gases, stars, Planets, and Comets. Mario visits many galaxies in his adventures through Super Mario Galaxy and Super Mario Galaxy 2.

Super Mario Galaxy series
The galaxy named Grand Finale Galaxy is home to Mario's planet (Mushroom World), while the Milky Way Galaxy is home to Earth. The galaxies in Super Mario Galaxy are notably much smaller than real galaxies, often being comprised of nothing more than a few small planetoids, most of which are in all different shapes and sizes. However, if one considers that the Mushroom Universe to be a different Universe to Earth, the laws of physics may be different to ours in where a Planet does not have to be spherical or a galaxy can be much smaller than a galaxy in our universe.

Galaxies are each categorized under different Domes which show Mario up to five galaxies and then gives him the option to fly to those galaxies. Each dome also has one Hungry Luma galaxy which can only be accessed by feeding a Hungry Luma the certain amount of star bits that it requires to transform into a galaxy.

Terrace

 * Good Egg Galaxy
 * Honeyclimb Galaxy
 * Loopdeeloop Galaxy
 * Flipswitch Galaxy
 * Bowser Jr.'s Robot Reactor
 * Sweet Sweet Galaxy (Hungry Luma)

Fountain

 * Space Junk Galaxy
 * Rolling Green Galaxy
 * Battlerock Galaxy
 * Hurry-Scurry Galaxy
 * Bowser's Star Reactor
 * Sling Pod Galaxy (Hungry Luma)

Kitchen

 * Beach Bowl Galaxy
 * Bubble Breeze Galaxy
 * Ghostly Galaxy
 * Buoy Base Galaxy
 * Bowser Jr.'s Airship Armada
 * Drip Drop Galaxy (Hungry Luma)

Bedroom

 * Gusty Garden Galaxy
 * Freezeflame Galaxy
 * Dusty Dune Galaxy
 * Honeyhive Galaxy
 * Bowser's Dark Matter Plant
 * Bigmouth Galaxy (Hungry Luma)

Engine Room

 * Gold Leaf Galaxy
 * Sea Slide Galaxy
 * Toy Time Galaxy
 * Bonefin Galaxy
 * Bowser Jr.'s Lava Reactor
 * Sand Spiral Galaxy (Hungry Luma)

Garden

 * Deep Dark Galaxy
 * Dreadnought Galaxy
 * Matter Splatter Galaxy
 * Melty Molten Galaxy
 * Snow Cap Galaxy (Hungry Luma)

Trial Galaxies

 * Bubble Blast Galaxy
 * Rolling Gizmo Galaxy
 * Loopdeeswoop Galaxy

Gate

 * Gateway Galaxy
 * Boo's Boneyard Galaxy (Hungry Luma)

Others

 * Grand Finale Galaxy
 * Bowser's Galaxy Reactor

Club Nintendo
Galaxies reappear in the Club Nintendo comic Super Mario: Verloren in der Zeit where they are the place where Mario and the intergalactic enforcers go.