|Status||Not yet established|
Galaxia was a possible future state for the human race, in which all planets, all humans, all life, and even non-living organic matter will be incorporated into one sinle organism. Galaxia is an alternative to the Second Galatic Empire that the Seldon Plan is trying to achieve.
At the time of the two books dealing with Gaia, Foundation's Edge and Foundation and Earth, Galaxia is conceived as a living organism which contains all the lifeforms and other non-living material in the galaxy. It is a utopia; the successor of Gaia. R. Daneel Olivaw founded Gaia with the purpose of Galaxia in mind, in order to be able to alter humanity for the better. However, since he could not tell whether this move would eventually hurt humanity, itself of almost unpredictable nature, and he therefore could not tell whether the Zeroth Law permitted it, he could not by himself make the decision to implement Galaxia. Hari Seldon's Psychohistory Project was a 'backup' initiated by R. Daneel Olivaw in the event that Galaxia was not determined to be the ideal course of action.
In 498 F.E., the time of Foundation's Edge, councilman Golan Trevize and historian Janov Pelorat, the protagonists, are maneuvered to Gaia so Trevize can decide whether the future of the Galaxy is to be guided by the First Foundation, Second Foundation, or Gaia. Trevize is stated to have the unique ability to deduce the correct solution to a problem, even with little or no information on the nature of problem itself. The book portrays it as a higher form of intuition, though Trevize has no actual psychic abilities. Trevize chooses Gaia, therefore Galaxia. This was done because R. Daneel Olivaw could not proceed with Galaxia for risk of harming humanity in the process.
In the novel Foundation and Earth, Golan Trevize, Janov Pelorat, and Blissenobiarella set out on a journey to find humanity's ancestral planet — Earth. The purpose of the journey is to settle Trevize's doubt with his decision at the end of Foundation's Edge to embrace the all-encompassing supermind of Galaxia.
From Foundation's Edge it can be surmised that Galaxia culminates in about FE 800-900 (or more precisely - R. Daneel Olivaw declines to merge with Janov Pelorat's mind as he is too old and will die in 30-40 years and elects instead to merge with Fallom's who being from Solaria will live another 300-400 years which will be enough for the completion of Galaxia), allowing for further Foundation stories to be interesting until that date, if the Estate of Isaac Asimov were to authorize further stories (Vis-a-vis Donald Kingsbury's novel, Psychohistorical Crisis). However, it is noted by R. Daneel Olivaw in Foundation and Earth that it would take several more centuries to bring Galaxia about.