So for millennia, there was nothing, a vast emptiness right before the next big explosion we know of as the Big Bang. The starship that merged Galan and the Sentience of the Universe emerged from this explosion, hurling through the universe that is reborn with new planetary star systems until it finally settles orbit around a planet from it’s gravitational pull.
A Watcher observed this spaceship and studied it. His findings were that this being was harnessing power it had never seen before. The Watcher knew of the impeding doom this entity would become.
The Watcher felt like intervening but could not as the only being aboard the spaceship was growing in power, as his purpose was to watch and record only. To never intervene of what was to become, even if he knew galaxies would die.
The cosmic being we know of as Galactus now departed, once again in a cocoon of his space vessel back into the void of space. He labored to create a new body suit that would help him regulate his awesome energies, transforming his ship into a new chamber for him to continue to rest and grow until his maturity.
Centuries past once again, the ship settles upon another planet called Archeopia that is more advanced, detecting the vessel and knowing it is not of the natural universe. The people detect the presence and determine it to not be disturbed. Orbiting Archeopia for years, it goes undisturbed until an interstellar war erupted. Mistaking the cosmic space cube as a possible weapon, it’s fired upon.
This awakens Galactus, his incubation has ended and he’s hungry.
He starts to devour the planet he was orbiting. Some of the Archeopia people manage to escape. Now that they’re without a planet. Being the first beings to witness Galactus and his hunger for worlds, they sail now through the galaxy for untold centuries as The Wanderers (first appearance in Thor #160).
Galactus spares parts of Archeopia from total destruction, longing for his home planet. As an agent of chaos, he also is an agent of creation. He takes what power he has to build Archeopia into a planet far more advanced than it previous was as Taa II.
Along with the planet, he builds a world ship so massive that the planets orbit it as if it were a star itself.
Taa II was a home created for a God.
Fun fact. The Wanderers were given sanctuary on Ego after their ship was ruined in a battle between Thor and Galactus. This was a cruel intention though as Ego’s true intention was not to provide a home to the Wanderers from Archeopia but rather to consume them, which he did soon after Thor departed.