Class M
From Memory Alpha, the free Star Trek reference.
In planetary classification, a class M planet or planetoid is characterized by an abundance of surface water and an atmosphere high in nitrogen, with oxygen and trace elements. M-class planets were also termed Minshara class by Vulcans during the mid-22nd century. 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, Vulcan, Cardassia Prime, Bajor, Romulus, Betazed, Ferenginar, and Qo'noS.| Planetary classification |
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| D • H • J • K • L • M • N • T • Y • Other classes |
[edit] Background
The term "class M" was first used in "The Cage" to describe the planet Talos IV.
Spock called the planet from TOS: "Return to Tomorrow" class M despite the atmosphere being ripped away, suggesting that class M goes beyond being able to support life. Alternately, he could have been saying that the planet prior to losing its atmosphere would have been categorized as class M.
According to the Star Trek: Star Charts, class M planets have ages that range from three to ten billion years and a diameter between 10,000 and 15,000 kilometers. They are located within the ecosphere of a star system.
