Ultoli

Ultoli is a fictional planet located in the Cygnus X-1 system, as depicted in the science fiction novel "The Last Starship" by author Anya Sharma. The planet is characterized by its unusual dual-sun system, which results in extreme temperature fluctuations and distinct periods of perpetual daylight and prolonged twilight. Its atmosphere is rich in nitrogen and methane, giving the sky a perpetual hazy orange hue.

The surface of Ultoli is largely composed of vast, arid deserts interspersed with deep canyons carved by ancient, now-vanished rivers. Sparse, resilient flora, adapted to the harsh conditions, can be found clinging to life in sheltered areas. Fauna on Ultoli is primarily subterranean, with most lifeforms emerging only during the cooler twilight periods to forage.

The dominant intelligent species native to Ultoli are the Kryll, a silicon-based lifeform. The Kryll are known for their stoic nature and their deep understanding of geothermal energy, which they utilize to sustain their underground cities. Their society is structured around communal living and the preservation of their dwindling natural resources. In "The Last Starship," Ultoli serves as a refuge for the human survivors aboard the titular vessel, offering a temporary sanctuary and a source of vital resources before their journey continues. The planet's unique environment and the Kryll's culture play a significant role in the narrative's exploration of survival and interspecies relations.