Welcome to Rasmussen’s Guide, a tool for those wanting more science in their science fiction.
It is for GMs running campaigns who need an alternate world with a logical ecology. Admit it, game worlds need internal logic, after all. Living animals do not spontaneously generate from nonliving matter, nor do they magically appear out of thin air. All living things metabolize, reproduce, grow, and adapt. They do not do these things in a vacuum. This planetary guide is a concise look at these lifeforms as they might evolve on a variety of planets, moons and celestial objects, using each world’s surface gravity to define its primary vertebrate Superclass and maximums.
From space at a distance, orange and blue atmospheric haze layers surround Titan. On a closer look from orbit, Titan has an atmospheric polar vortex — a swirling hydrogen cyanide (HCN) gas cloud — over the moon’s south pole. Upon closer examination, seasonal methane rainstorms produce wet patches visible from orbit. At the surface, rust-colored clouds appear in a blue sky. The clouds are made of methane ice and cyanide gas. The surface appears orange with white boulders and rocks. The plentiful boulders are rock-hard water ice.