Usk bears the scars of an ancient collision between the planet and a former lunar body that used to rotate around the planet. Gravitational pull from the sun launched the moon deep into the core of the planet without destroying Usk altogether. Because the moon bore a narrow but deep hole through Usk's surface, resulting in a relatively low amount of debris being ejected from the ground into the atmosphere. The planet’s close proximity to the sun meant that any accretion blown off the planet crust was either trapped in the atmosphere by the planet’s gravity or promptly vaporized by the rays from the sun before it could coalesce into another moon. As a result, Usk has no moons orbiting it to this day.
Usk’s topography and climate reflect this violent history. A now-permanent magma tunnel from Usk’s core to the surface, bored by the historical collision, feeds a large lava lake that has coalesced over the original impact site. The lava flash froze as it approached the poles of the planet. This has created crystalline glaciers on the planet composed of equal parts water and silicates, resulting in a toxic yet visually stunning geography in the colder parts of the planet. Lava escaping the tunnel across the planet’s equator cooled at a steadier pace, which allowed rich mineral deposits to build over a continuous cycle of lava flow, solidification, and accumulation. Over time, a few pocket deserts were created in the mountain regions of the planet by chance due to sheltering from the colder temperatures and closer proximity to the thermal heat emanating from the thin planet crust. The planet atmosphere, largely formed by the historical collision and maintained by constant emission from the lava lake, is filled with toxic particulates that also dampen the light from the nearby sun. This has resulted in a colder than expected temperature for Usk than one might expect given its proximity to its system’s star.
The planet’s first known permanent residents settled in the mountain region. This was driven by practical considerations: prospectors suspected that most resources could be extracted from the mountains, and the temperature was most tolerable around the peaks of the equator because more sunlight was able to break through at that altitude. Early miners created a sprawling capital city of Farwen, where most workers inhabited when they were not in mines. As the planet’s economy grew, however, the cities spread out with it to meet the demand for more labor.