Terrestrial Planets

These are the planets most like the Earth.

 

–

• E, F, G (10-15k km),
  
• H (8-15k km) desert, L (10-15) barren,
  
• M,
  
• N (10-15) Venus/reducing gases,
  
• O (10-15) 80%water, P (10-15) >80% water,frozen.
  
• Q (4-15) (could be some of the dwarf terrestrials) variable star or eccentric orbit, XYZ
  

Proto-Active

Epi-stellar 

• Jani-Vesperian:  (possible L-class) atypical, borderline Vesperian worlds, either most of the surface water frozen out on the night-side, or the volatiles having been depleted during the planetary formation process.  Native biology is sustained by the thickened atmospheres, but due to the lack of large bodies of water they suffer major climatic extremes. Most surface water located in the twilight regions, as well as the biomass.
• Eu-Vesperian:  mature Vesperian worlds, typically support lush biomes.  Depending on continental configuration, and amount of surface water, there may be a night-side ice cap of varying size and thickness — the oceans and, to a somewhat lesser extent, the atmosphere aid in evenly distributing the heat of the star across the globe, leaving only extreme temperatures under the star and near the night-side polar cap.
• Bathy-Vesperian:  high temperature, deep oceanic basins, atmospheres quite dense. tend to have complete cloud cover, and a lack of any sort of night-side ice cap. atmosphere and ocean tends to evenly distribute global temperatures, although there may be an oceanic “dead zone” near the surface directly underneath the star. Temperatures in this region can easily reach nearly 250 degrees Fahrenheit.
• Chlori-Vesperian:  (possible L-class) biospheres that release free chlorine through photosynthesis. can only form when there is a high percentage of hydrogen chloride in addition to the water. believed to be exceptionally rare, especially when taken with the relative rarity of Vesperian worlds themselves.

Telluric

Arid

Tectonic

• Eo-Gaian:  young Gaian, age roughly between 800 MYO and 3 BYO, rich and thick carbon dioxide and methane atmospheres. The presence of such a thick atmosphere, generated largely by methanogen bacteria, creates a major greenhouse effect and a fairly active water cycle. atmospheric methane forms thick layers of hydrocarbons in the upper atmosphere, covering the planet (appear) in an orange haze.
• Meso-Gaian:  Age roughly 3 – 4 BYO.  Life prominent microbiological ecosystems.  Atmospheres largely cleared of methane, although carbon-dioxide remains prevalent. As the present microbiological forms of life become more complex and evolve, however, they begin to release oxygen into the atmosphere, slowly transforming the planet into a Eu-Gaian state.
• Eu-Gaian:  Class M, mature Gaian, fully developed geological, hydrological, and biological systems. Life usually quite diverse, although there may be cases where evolution beyond simple microbial forms never occurred, simply because there was no environmental pressure to do so. even in these cases, the life present produces oxygen and carbon dioxide as a bi-product, making the atmosphere unique and generally friendly for non-native lifeforms. In short, these are the archetypical “blue marbles” that are so covetously sought after by Humankind.

• Bathy-Gaian:  (Class O) could be regarded as cooler and relatively drier versions of Bathy-Pelagic, or very hot and high surface pressured Eu-Gaian.  Appear Superficially: similar to true Cytherean, their massive atmospheres consisting of carbon dioxide, and their surfaces concealed beneath dense cloud layers. surfaces are under 10-100 bars of pressure and 200-400 degrees Fahrenheit, although the high pressure keeps that water from evaporating. surface is covered by a global ocean ~7 km deep.  Life nearly always present, with more complex forms found in the deeper waters. ocean bottom is barren and largely anoxic, but possesses its own particular set of biomes.  Plate tectonics present, but continental crust almost entirely missing.
• Chloritic-Gaian:  Class H (desert)?  Quite rare, orbit usually around warmer G and cooler F-type stars.  Typically little / no complex surface life, with most forms remaining in marine environments.  Marked by large quantities of integrated chlorine in the environment, which is integral to any biomes present.  Appearance:  oceans and clouds somewhat greenish, while continents usually somewhat barren brown.
• Amu-Gaian:  15-85% ammonia ocean coverage.  Atmospheres methane-rich.  Cold climates despite the presence of a greenhouse gas, with the ammonia content in the water aiding in keeping them liquid.  Typically orbit cooler K and M-type stars.  Life can be present, but employs processes to balance the mixed ammonia-water chemistry of their environments.
• Thio-Gaian:  based on sulfur photosynthesis rather than oxygen photosynthesis. The protein S8, which is produced in photosynthesis, is carried to the upper atmosphere and shields the surface from radiation, while the sulfuric acid which is also produced by this process is used to produce sulfur dioxide by plankton-like fauna-forms or microbes, which is then produced by other life forms, which in turn produce carbon dioxide and hydrogen sulfide as a waste product.  These are then used by the flora-forms to continue the cycle.  Appearance: usually yellowish skies, and soil may be stained red from extensive rust deposits.
• Gaian-Gelidian:  settled into a frozen climatic equilibrium, either due to biological or orbital placement reasons.  Complex life, if it develops, or remains extant, tends to be concentrated within sub-glacial seas. However, if such a world has entered into this state after the evolution of complex life, then that life will have most likely gone extinct.  Atmospheres:  oxygen-deprived and nitrogen-rich. Air usually devoid of major cloud formations, and with Aeolian forces being dominant, the land areas will likely be barren of ice as past glaciers will no longer have the means to grow, and their surface areas will be desiccated by the wind.
• Post-Gelidian:  (later examples: Class L) begun to lose large amounts of surface water, typically due to the beginning of their star’s evolution off of the main sequence.  Early stages: dense, cloud-covered, water-rich atmospheres.  Often, plant life will undergo an explosion of diversity and growth.  Later examples of these worlds : largely desert, very restricted ,highly saline seas located in the lowest elevations. Life, if it remains, will be microbial extremophiles.

• Eo-Amunian:  Age: young, atmosphere of gaseous ammonia, methane, small amounts of water droplets. As the planet ages and cools, these components will be broken down into nitrogen, carbon monoxide, and a hydrocarbon ‘tar’ that will rain down on the surface. Ammonia oceans will condense on the surface during this period, and the earliest forms of life will develop. These organisms will be acidophilic due to the presence of dissolved water, but they will begin converting the present oxygen into sulfur dioxide as a part of their metabolic processes.
• Meso-Amunian:  have cooled, atmospheres composed almost entirely of nitrogen and carbon monoxide.  Primitive life will begin to use a hydrogen-methane cycle, thus increasing the amount of methane within the atmosphere. Cycles which incorporate nitrogen and carbon monoxide will also be used and eventually incorporated into the growing planetary ecology.  Temperature:  as levels of methane increase the planet will once again begin to warm.
• Eu-Amunian:  often considered to be ammonia analogues of Gaian.  Plate tectonics, dynamic climate, differences in climate, hydrology, meteorology, and geology, all of which are significant.  Sometimes an advanced biosphere.  Colder than Gaian.  Orbit: forming beyond the habitable zone, (cold or hot?).  Receive enough energy to melt ammonia. Because ammonia ice is denser than liquid ammonia, polar caps are located beneath the polar oceans.  Appearance : greener than Gaian, because of the gases involved, and their atmospheres usu. dense and rich in nitrogen, with significant amounts of methane and hydrogen.
• Bathy-Amunian:  much stronger greenhouse effects than Eu-Amunian.  Atmospheres very dense , retain large amounts of carbon monoxide and ‘humid’ with ammonia. capable of supporting liquid ammonia at higher temperatures because of the greater atmospheric pressure. may contain significant amounts of volcanic and possibly sulfuric gases, depending on the inherent geological activity. Large portions of the extant biomass located in the upper atmosphere, where it is cooler, as well as within the oceans and seas. Such organisms are extremophiles by the standards of the rest of the planet.  The extreme worlds, highest in pressure, can actually support liquid ammonia at temperatures which are more common on Eu-Gaian.

• Eu-Tartarian:  often considered to be methane analogues of Gaian worlds.  Plate tectonics, dynamic climate, differences in climate, hydrology, meteorology, and geology, all of which are significant.  Sometimes an advanced biosphere.  Colder than Gaian.  Orbit: forming beyond the habitable zone, (cold or hot?).  Receive enough energy to melt methane, atmospheres usually dense and rich in nitrogen, with significant amounts of methane and hydrogen.

Oceanic

• Eu-Pelagic:  200+ times the water found on Eu-Gaian worlds.  Atmospheres oxygen rich due to several ocean-related factors. Some worlds have an oxygen content > 90%.

• Bathy-Pelagic:  highest water amounts, global oceans 20-200+ km deep, atmospheres extremely dense. intense atmospheric pressure keeps the ocean liquid, and keeps it from boiling away. surface evaporation and re-condensation is so high that the demarcation line between ocean and atmosphere is difficult to determine.  Surface temperature can reach 200+ degrees Fahrenheit,

• Pelagic-Gelidian:  (Class P)  crusts: frozen over due to a variety of reasons, most often a dimming star. Tidal or subsurface geological stresses often create cracks in the global ice coverage, allowing a thin atmosphere oxygen , nitrogen to form. Were it not for constant replenishment from these rifts, the atmosphere would desiccate within 3 million years.

–

Superclass E-G

Class E:

–

Class F:

–

Class G:

–

Class H:

–

Class L:

–

Class M:

–

Class N:

–

Class O:

–

Class P:

–

Class Q:

–