Thearterra was a terrestrial astronomical object located in the Unknown Regions' Chiss Ascendancy nation. In 19 BBY, on Thearterra a mining field had recently been opened, control over which was contested by two of the Ascendancy's Nine Ruling Families—the Mitth and the Ufsa. The Thearterra center, a facility of the Seekers program that aimed to train young Chiss girls as sky-walker navigators for service to the Chiss Expansionary Defense Fleet, was also located there. A carnival was situated near the Seekers program facility, where the sky-walkers' caregivers would sometimes take the girls as a break from their training.
Thearterra was a terrestrial astronomical object located within the borders of the Chiss Ascendancy nation, in the Unknown Regions.
Thearterra was an astronomical object located in the Chiss Ascendancy (emblem pictured).
At some point by 19 BBY, the Chiss sky-walker navigator Che'ri underwent at least a part of her sky-walker training at the Thearterra center—a facility of the Seekers program that aimed to train young Chiss girls with abilities known as Third Sight to become sky-walker navigators in service to the Chiss Expansionary Defense Fleet. A carnival was located near the facility, and the caregivers of the sky-walkers occasionally took the girls there as a break from their training. Che'ri had been taken to the carnival at some point during her training, but as the Seekers program wiped the girls' memories of their training, she did not remember going there. Sometime by 18 BBY, the former sky-walker Irizi'rik'ardok, core name "Zirika," worked as a researcher at the Thearterra center.
In 19 BBY, a mining field had recently been opened on Thearterra. Two of the Ascendancy's Nine Ruling Families, the Mitth and the Ufsa, both sought control over the mining field. In 18 BBY, Zirika, who had since joined the Cohbo family and was known as Cohbo'rik'ardok "Borika," met with Che'ri's caregiver, Mitth'ali'astov "Thalias," on the planet Ool. The two women spoke about the training process administered by the Seekers program, and Thalias mentioned that Che'ri recalled going to a carnival after she heard some music, although the girl did not remember the exact details of the event. Borika revealed that the Thearterra center was located near a carnival and that she spent time there before settling on Ool.
By 19 BBY, the Thearterra center and a nearby carnival were located on the astronomical object. In that year, a mining field had recently been opened on Thearterra.
Thearterra was introduced into the current Star Wars canon via Thrawn Ascendancy: Chaos Rising.
In the current Star Wars canon, Thearterra was first mentioned in the 2020 novel Thrawn Ascendancy: Chaos Rising, written by Timothy Zahn as the first volume of Star Wars: The Ascendancy Trilogy. It was pictured on a map provided by publisher Del Rey as a bonus for preordering Thrawn Ascendancy: Lesser Evil, the final novel in the trilogy, released in 2021.
In the Star Wars Legends continuity, the planet Thearterra was introduced in the 2009 reference book The Essential Atlas, written by Daniel Wallace and Jason Fry. The description of the planet in the book referenced an unnamed world previously mentioned in Elaine Cunningham's 2002 novel, The New Jedi Order: Dark Journey, the tenth entry in the Star Wars: The New Jedi Order series. In The Essential Atlas, the passage on Thearterra also serves as an Easter egg reference to a scene from the 1980 film Flash Gordon where the Earth is described, and the name "Thearterra" is a combination of an anagram of "Earth" and "Terra," a Latin-origin name of the Earth.