M-Class Planets

Back in the 1960s, the tv show Star Trek developed some conventions, basically for the convenience of storylines and production budgets.

Firstly, aliens, for the most part, looked like humans, albeit with a few superficial variations (pointy ears, green skin etc). Secondly, all the planets the crew of the Enterprise visited would be essentially like Earth. The gravity would basically be the same. The air would be breathable, the temperature within the boundaries of human tolerance.

These kinds of worlds are called M-Class planets. Every time you see someone beaming to the surface of a planet in any episode of any of the incarnations of Star Trek, materialising in only their neat uniform and breathing-in the local air, this is an M-Class planet. Initially, there seemed to be no particular reason why Earth-like planets were designated M. However, a world of supplementary material has been created around the Star Trek franchise, including detailed star and planet charts, which explain the different kinds of celestial bodies and how they are arranged.

Earth shares its fundamental geological, atmospheric, orbital and life sustaining qualities with all other M-Class worlds, and it seems that M stands for a word in the Vulcan language — Minshara. I don’t know what Minshara means. It might be a place, it might be a concept, it doesn’t really matter. M-Class is a necessary conceit for Star Trek. It opens up endless possibilities in this fictional future. However, within the boundaries of current human knowledge, among the possible trillions of planets that are out there, we only really know about one that is capable of supporting life.

As far as we know, there is only one M-Class planet.