Class M

Earth is considered the quintessential Class M planet.

In planetary classification, a Class M planet is a 'Terrestrial' planet. They have an age that ranges from 3-10 billion years and a diameter between 10,000 and 15,000 km. They are located within the Ecosphere of a solar system. A Terrestrial planet is categorized by an abundance of surface water and an atmosphere high in nitrogen with oxygen and trace elements. Life is often abundant on Class M planets; they contain extensive vegetation, animal life and often have native humanoids.

Examples of Class M planets include: Earth (Sol III), Vulcan, Cardassia Prime, Bajor, Romulus, Ferenginar, Skoria and Qo'noS.