In Super Mario Galaxy we learn of the backstory of the motherly protector of the cosmos, Rosalina; how she met a young baby Luma which had crashed in a downed Starshroom spaceship on her home planet; how she and the Luma went in search of the Luma's "Mama;" how Rosalina was accepted as the mother of the star-children.
Fact: Luma specifically states that her Mama is coming for her in a comet.
Fact: It is also heavily implied that the Gateway Galaxy was Rosalina's home planet.
Fact: The Observatory also functions as a comet.
Fact: At the secret ending of the game, we see Rosalina depart from the Gateway Galaxy...leaving behind a young Luma in the same type of downed spacecraft.
So what exactly is going on here? Is Rosalina caught in some sort of endless time loop, where she constantly rescues the baby Luma after losing it? Or is there another explanation to this mystery?