The planet Ariadne in the process of Gnosifying, in which it becomes the Cathedral Ship, during Episode I.
The Ariadne Incident is a space-time anomaly that was produced as a result of the Zohar Emulators going out of control, when the U-TIC Organization was running connection experiments with the emulators at a facility located on the planet Ariadne. Ariadne completely disappeared within the anomaly, along with with its 1.5 billion inhabitants. However, there were a few spaceships that had managed to escape. These included ships owned by the U-TIC Organization.
The planet became a Gnosis called the Cathedral Ship, which is a dungeon in Episode I.
According to the database in Xenosaga Episode III: Also sprach Zarathustra, a connection, a Zohar Link Experiment, was made to the link experiment's director Andrew Cherenkov and the reason behind Ariadne being the location for the connection experiments.