Celsiusa

Celsiusa is a fictional planet featured in the science fiction novel "Project Hail Mary" by Andy Weir. The planet is home to a sentient, non-humanoid species known as the Astrophage. Celsiusa is characterized by its extremely cold environment, hence its name, which evokes the Celsius temperature scale. The planet's surface is largely covered in ice and experiences prolonged periods of darkness. The Astrophage, the sole known inhabitants, are microscopic, energy-eating organisms that form large, complex colonies and possess a collective intelligence. Their existence is intrinsically linked to the energy sources available on Celsiusa, which they consume to reproduce and thrive. The novel explores the ecological and evolutionary adaptations of the Astrophage to their harsh home world and the implications of their discovery for humanity. Celsiusa serves as a crucial setting for understanding the Astrophage's origins and their potential threat to Earth.