Thearterra

Thearterra was a planet of the Chiss Ascendancy in the Unknown Regions.

Thearterra was an insignificant world, perpetually racked by volcanoes, hailstorms, and groundquakes.

Behind the scenes
The Essential Atlas refers to it as "an obscure body in the S-K system", which are the exact words used by General Klytus to describe Earth to Ming the Merciless in the opening scenes of the 1980 film Flash Gordon.