In 79 episodes of Star Trek – The Original Series the Enterprise will visit many planets, sometimes inhabited by humanoids or by alien lifeforms. - Class W: Planets of the “water class” are like Earth, orbiting a star in the habitable zone where temperatures allow liquid water to exist. - Class P: “Pulsar class” planets orbit the collapsed remains of a star and are constantly bombarded by high radiation and exposed to strong magnetic fields. Star Trek aired three years before the first manned Moon landing and virtually nothing was known about the geology of other planets or moons. Yet the authors of Star Trek got many things right.

Source: Forbes September 08, 2018 14:00 UTC