Introduction, Guidelines and Terminology Edit
A common mistake to make is to assume that the Mario Universe is identical to ours in the way it works, and that the galaxies (seen in Mario Galaxy) are lightyears apart, as is the case in ours... However, I propose that Mario's Standard universe, which shall be shortened to the "Galaxiverse" to make it easier to refer to, is very different in this law... And they are much closer than one would assume. The term Galaxieverse will be used as it refers to the universe seen in Mario Galaxy.
Due to the fact the 120 star ending of Mario Galaxy 2 implies that the events taken place in said game was just a book written by Rosalina, it will NOT be taken as a canon source. Also, despite arguements of whether the name should be taken seriously or not, the Galaxy homing Mario's Planet will be referred to as the "Grand Finale Galaxy", as it was at the end of Mario Galaxy 1. With these rules in place, we can begin:
The basics Edit
The galaxies in Mario Galaxy are very hard to define as "galaxies". A galaxy is a group of stars, whilst in Mario Galaxy they appear to be more of a "planetary cluster". This means we can say that the definition of galaxies in the Galaxiverse is different to that of our universe. This will instantly help us see the difference, as this helps us see a clear reason why these galaxies are not as far apart as they are in our universe.
A simple rule stated in Mario Galaxy is that power stars must be collected to power up the Comet observatory, so it can view further into the universe until it has enough power to fly to the centre of the universe. So with ever power star collected, the further Mario can venture. Using this rule, we can see that the order which Mario accesses each galaxy shows it's distance from the Grand Finale Galaxy, where the Comet observatory is parked. This would make Good Egg Galaxy (the first galaxy accessed from the Comet Observatory) the closest, or one of the closest, galaxies to Grand Finale Galaxy.
One can seperate each galaxy into groups. Whilst there are some galaxies which don't fit into these groups, the basic separations are Terrace Galaxies, Fountain Galaxies, Kitchen Galaxies, Bedroom Galaxies, Engine Room Galaxies and Garden Galaxies, each being further from the Comet Observatory than the last. Since the set place for the Comet Observatory in Mario Galaxy is the Grand Finale Galaxy, we can see this rule applying to the galaxy itself, and not the starship, which can move accordingly to change the distance from a galaxy (like it did when it travel to the centre of the universe).
Another important Galaxy, which is outside these groups, is the Gateway Galaxy, the first Galaxy of the game. This can either be seen closer to the Grand Finale Galaxy than Good Egg Galaxy or inbetween Engine Room Galaxies and Garden Galaxies, which is when the galaxy can be accessed at any time.
The introduction of Mario Galaxy and the position of Gateway Galaxy Edit
In the introduction to Mario Galaxy, after several minutes into the game, Peach's Castle is taken into space with Mario onboard. This catches the eye of Kamek, who blasts Mario away when they are above the Mushroom Planet (Mario's Planet, where most of the games take place). Due to the speed and momentum that Mario takes on his path, we can say he didn't land too far from his planet, however we don't see a direct path. To strengthen this theory, we see Luma chase after Mario, but he flies downwards, towards the planet. This implies that Mario's landing spot is very near to the planet.
Mario wakes up on a planet in the Gateway Galaxy, which implies this to be his landing spot. Due to this, it's very likely it's close to Mario's planet. To explain why it is inbetween the Engine Room Galaxies and Garden Galaxies is that the access point to it required a grand star to power the "teleporting pad" that takes Mario from the Engine Room floor to the platform with the portal to Gateway Galaxy.
Further proof of the Gateway Galaxy being near to Mario's Planet is that Rosalina goes there to view the planet, meaning it has to be near enough to actually view the planet. Because otherwise, what is the point? Since if she cannot see the planet clearly, then the planet is not good enough of a viewing point.
The ending of Mario Galaxy and the position of other Galaxies. Edit
The ending of Mario Galaxy, when Mario welcomes a new galaxy into existence just before the credits, zooms out from Mario's planet to show several other planets. These planets can be identified as those from Good Egg Galaxy (a Terrace Galaxy) and Gusty Garden Galaxy (a Bedroom Galaxy), which appear pretty close together, despite being different galaxies in different groups. This not only proves that the galaxies are indeed closer together than in our universe, but also that the groups of galaxies are close!
TO BE CONTINUED. MORE RESOURCES ARE NEEDED AND WILL BE TAKEN CARE OF AS SOON AS POSSIBLE.