Class M: Terrestrial planets are robust and varied
worlds composed primarily of silicate rocks. Located
in a star system's habitable zone, most are
temperate worlds with vast blue oceans and wide
swaths of verdant forest. However, conditions can
vary greatly between worlds and still be considered
Class M; as long as the surface is between 20 and
80 percent water, the climate is generally
temperate, and the atmosphere made of oxygen and
nitrogen, even dry rocky worlds and cold snowy
planets can be Class M.
worlds composed primarily of silicate rocks. Located
in a star system's habitable zone, most are
temperate worlds with vast blue oceans and wide
swaths of verdant forest. However, conditions can
vary greatly between worlds and still be considered
Class M; as long as the surface is between 20 and
80 percent water, the climate is generally
temperate, and the atmosphere made of oxygen and
nitrogen, even dry rocky worlds and cold snowy
planets can be Class M.
| AGE DIAMETER LOCATION ATMOSPHERE SURFACE COMPOSITION SURFACE TEMP HABITABILITY |
4-10 billion years old
10,000 - 15,000 kilometers
ecosphere
nitrogen, oxygen, argon
abundant surface water; temperate
climate
silicon, iron, magnesium, aluminum
-89°C to 58°C
prime conditions for vast populations
of plant, animal, and humanoid life
10,000 - 15,000 kilometers
ecosphere
nitrogen, oxygen, argon
abundant surface water; temperate
climate
silicon, iron, magnesium, aluminum
-89°C to 58°C
prime conditions for vast populations
of plant, animal, and humanoid life
