The Terrestrial group includes rocky worlds that tend to range in mass between 0.02 and 5.0 times that of the Earth. They are massive enough to have geological activity, a magnetic field and an atmosphere.
These are Terrestrial worlds which are still in the process of forming.
- Proto Lithic - World with an extremely hot or even molten surface, still in the process of formation. They may have hydrogen/helium atmospheres.
- Proto Carbonic - Carbon rich world with an extremely hot or molten surface. Their atmospheres will be rich in methane, as well as hydrogen and helium.
- ProtoGelidic - A new world forming beyond the snow line, mostly of water and ices. However, they are hot enough to have liquid water surface and an atmosphere of water vapour.
These are Terrestrial worlds tidally locked to their primary star.
Such worlds do not support a continuous hydrological cycle. They tend to have thick atmospheres due to geological outgassing, and may undergo constant resurfacing due to either continuous or cataclysmic events.
These are dry Terrestrial worlds that support a limited hydrological cycle which may include an accompanying ecology.
Such worlds support a continuous hydrological cycle and often an accompanying biosphere. The surface crust is split into continental and oceanic crusts, and they have an active geologic cycle with a magnetic field.
- EoGaian - Young Gaian worlds, up to a few billion years old. They have carbon dioxide or methane atmospheres, and possibly limited bacterial life.
- MesoGaian - A world with a prominent microbiological ecosystem. The atmosphere may contain large levels of oxygen.
- Necro Gaian - A world where all life has died.
- CryoGaian - A frozen Gaian world where life lives on in the deep oceans.
- EuGaian - Mature Gaian world with a full biological ecosystem. They are divided according to the amount of water cover.
- BathyGaian - Hot ocean world with no surface land. They generally support life deep within the oceans.
- ChloriticGaian - Simple life with a Chlorine filled atmosphere.
- AmuGaian - Cold world with ammonia filled water ocean.
- ThioGaian - Gaian world based on sulphur photosynthesis rather than oxygen.
- GaianGelidian - Gaian world locked in a frozen state.
- PostGelidian - Gaian world which is beginning to lose most of its surface water.
Carbon rich worlds, deprived of water, silicates and other oxygen-bearing compounds. They are cold worlds, which have an Ammonia based hydrological cycle. Life tends to evolve in liquid ammonia rather than in water. Any water there is consists of hard ice, taking the place of rock.
- EoAmunian - Young Amunian world with an atmosphere of ammonia, methane and water droplets. May have Ammonia oceans towards the end of this cycle.
- MesoAmunian - A cooled Amunian world with nitrogen/caron-monoxide atmospheres.
- EuAmunian - Ammonia versions of EuGaian worlds. Have a biosphere, though it's incompatible with human life.
- BathyAmunian - Warm ammonia based world with a thick atmosphere that allows Ammonia to stay liquid at warmer temperatures and pressures.
Rich in methane and carbon compounds.
These are terrestrial worlds with a global ocean tens of kilometres deep.
There are geologically active worlds covered in global oceans of liquid Ammonia.
- Nunnic - Global ocean of liquid ammonia
There are geologically active worlds covered in global oceans of liquid Methane.
- Teathic - Global ocean of liquid methane