Earththe

Earththe is a fictional terrestrial planet widely used in science fiction, speculative geography, and world-building as a stand-in for Earth to explore questions of planetary habitability, climate, and biospheres. It is not a real celestial body.

In typical renderings, Earththe is described as being Earth-like in size and composition, with a radius near 1.0 Earth radii and a mass around 1.0 Earth masses, and it orbits a sun-like star within the habitable zone. Models often assume a nitrogen–oxygen atmosphere and surface oceans, but depictions vary, allowing for differing climates, geologic histories, and levels of atmospheric evolution. The world may feature plate tectonics, mountain ranges, river systems, and ice caps, enabling study of long-term climate stability and habitability under various solar and atmospheric scenarios.

Name and origin: The term Earththe appears in pedagogical materials and fiction as a linguistic variant designed to distinguish a familiar world from our own Earth while preserving recognizable features. It is an invented concept rather than an astronomical discovery.

Uses: Earththe is employed as a tool in education and storytelling to compare planetary processes—such as atmospheric chemistry, planetary albedo, and oceanic circulation—with Earth, without asserting the existence of a separate planet in our sky.