Planeetan

Planeetan is a fictional terrestrial planet in the science fiction setting known as the Tranquilis Cluster. It orbits a Sun-like star at about 1.2 astronomical units, with a year of roughly 1.3 Earth years. A rotation near 23 hours and an axial tilt around 24 degrees produce Earth-like days and seasons.

Physical characteristics: Planeetan is near Earth-sized, with a radius about 1.0 R⊕ and a mass close to 1.05 M⊕. Its surface consists of continents and oceans, with moderate tectonic activity and a silicate-iron interior.

Atmosphere and climate: The atmosphere is nitrogen-dominated with trace oxygen, yielding a surface pressure near 1 bar. Global mean temperatures sit in the mid-teens Celsius, with regional variation from temperate forests to subtropical coasts.

Geography and hydrology: Oceans cover roughly 60–70% of the surface. Major landmasses and coastlines are shaped by plate tectonics; mountains and volcanic arcs appear in several regions, influencing climate and biodiversity.

Life and exploration: In-universe sources describe microbial ecosystems and, in some narratives, more extensive flora. Exploration includes orbital surveys, landers, and sample-return missions conducted by regional space agencies, with occasional long-term outposts depicted in later timelines.

Culture and references: Planeetan serves as a recurring setting for ecological and sociopolitical stories within the Tranquilis Cluster, making it a common reference in speculative astronomy and fiction.