To'ul'h Prime
To'ul'h Prime
Galaxy The Milky Way
Region Near NGC 6633
System H'tat'sa'thoss
Suns H'tat'sa'thoss
Moons None
Rotation period 19 h 12 min
Class Terrestrial, Gaian-Cytherean
Diameter 14,086 km
Mass 1.45 Earth
Atmosphere Greenhouse, dense
Climate Chaotic, constant temperatures
Gravity 1.2 g
Primary terrain Ocean, mountain, plateaus, forests
Surface water 45%
Primary languages To'ul'hoss
Government AI-cracy
Population 140,000,000 near-baseline To'ul'hs
Demonym To'ul'hian, To'ul'hese
Behind the Scenes
Universe Orion's Arm
Creator Stephen Inniss

To'ul'h Prime or Tohul is the second planet from the star H'tat'sa'thoss, with a naturally-evolved biosphere in which its native intelligent extraterrestrial To'ul'hs made first contact with Terragens in the Orion's Arm science fiction universe.[1]

Physical characteristics Edit

To'ul'h Prime has a radius of 7,043 km, thus having a surface area of 623.3 million km2 and a volume of 1.4634·1012 km3.

With 1.45 Earth masses or 8.7194·1024 kg, To'ul'h Prime has a density of 5.958 g/cm3, making it 8,7% more dense than Earth.

The aforementioned mass and radius yield a gravitational acceleration of 11.732 m/s or ~1.2 g on the surface.

The planet orbits its primary at a distance of 0.8 AU or about 119.7 million km, with an average orbital speed of 21,332 m/s and an eccentricity of 0.05.

To'ul'h Prime's atmosphere is 50% carbon dioxide, 38% nitrogen, 9% oxygen and 3% water vapor and other gases. It exerts a surface pressure of 62.2 atmospheres.

The surface temperature is about 135 ºC, or 408 K.

Natural history Edit

To'ul'h Prime rotation

To'ul'h Prime without its clouds.

To'ul'h Prime is an atypical example of a primeval Venus-like planet that narrowly avoided a runaway greenhouse effect, preventing the evaporation of its oceans while conserving a thick atmosphere. In real life, Earth also used to be like To'ul'h Prime, but the collision with proto-planet Theia eliminated the primeval thick atmosphere avoiding the risk of suffering a runaway greenhouse effect.[2]

Since To'ul'h Prime lacks a moon, it has no neighboring body to transfer angular momentum into, still keeping a quick rotation. Along with its Earth-like size, a strong magnetic field is generated due to this and plate tectonics has been going on for billions of years.

The initial runaway greenhouse effect left the planet with a 45% water coverage. The atmosphere preserved many volatiles needed for life.

Abiogenesis took place once as on Earth or other Gaian worlds, beginning with single-celled prokaryotic life. Biochemistry is analogous to that of terrestrial life, however, proteins and enzymes are hyperthermostable and some do not denature until reaching temperatures of 150 ºC.

Within this hot environment, (hyper)thermophilic life thrived and diversified through evolution. Certain organisms are able to live in the colder, Earth-like temperatures of the upper atmosphere, becoming extremophiles from To'ul'h standards.

Current environment Edit

Surface gravity is 20% stronger than on Earth.

To'ul'h Prime is covered by a thick, cloudy and particulate-rich atmosphere. While the bare atmosphere would already reflect a great deal of sunlight (like Venus does), airborne photosynthetic life makes the surface completely dark, only lit up by occasional lighnings.

By volume, carbon dioxide constitutes half of the atmospheric composition, creating a powerful greenhouse effect. Though temperatures fluctuate between 120 and 140 ºC, with a pressure of 62.2 atmospheres water does not boil until reaching 286 ºC.

A dense atmosphere combined with nearly no axial tilt mean that temperature changes in To'ul'h Prime depend on altitude rather than latitude and that there are no seasonal changes. On the sea level, uniform global temperature prevents thermal gradients needed for circulation, so oceans are anoxic after 100 meters deep.

The high fraction of carbon dioxide in the atmosphere also acidifies the oceans, since it partially dissolves in water releasing protons. Together with traces of dissolved sulfuric acid, water in rain and rivers has a pH of 4 (moderately acidic). Water varies from fresh to hypersaline.

The hydrosphere covers about 45% of the crust or roughly 280.4 million km2. Unlike Earth, To'ul'h Prime has more land than sea, with ocean basins being only half-full. Being geologically active, subduction zones might be present on land then, an uncommon phenomena on Earth.

On the land, the six continents[3] are actually plateaus and there are no deserts, since rainfall is more or less uniform. It can also be inferred that rain is more common than on Earth, since a particle-rich air offers more area to condense water droplets.[4] However, instead of plant life, the dark, wet and warm surface offer an idoneous opportunity for fungi to form authentic 'forests', feeding upon dead creatures and all the biomass falling from above.

Biosphere Edit

To'ul'hian biochemistry is comparable to Earth life. It uses carbon compounds, water as solvent and even some organisms use oxygen for catabolism or produce it through photosynthesis.

Proteins are most likely thermostable, with amino acids forming a lot of hydrogen bonds and disulfide bridges (a bond between two cysteines).[5] Luckily, sulfur is more common on To'ul'h Prime, triggering their synthesis. Higher temperatures mean that enzymes make metabolism faster, ultimately making evolution itself faster.

Some differences come with the use of metals, though. The H'tat'sa'thoss System has a greater metallicity, which combined with To'ul'h Prime's hot, wet and acidic environment, results in mercury, tin and antimony being volatile and taking part in the metabolism of the To'ul'hs themselves.

Phylogenetically, all current To'ul'hian life can be divided into three large groups, all of which ultimately trace back their origins to single common ancestor 2 billion years ago.[6] Each of these groups began as a 'prokaryote group', eventually producing three unrelated branches of eukaryotic life.

  • Photosynthilia (primary skyplankton) - Contains three kingdoms and thrives on the clouds at 35 ºC.
    • Skyalgae - Photosynthetic autotrophs, they are the most diverse kingdom and can be divided into 4 phyla.
      • Blue
      • Brown
      • Green-golden
      • Red
    • Skyfungi - Saprophytes (heterotrophs) and retain little or no photosynthetic capability.
    • Skyzooplankton - Though heterotrophic and mobile, some still retain photosynthetic capability.
  • Thermophilia (thermophiles) - They thrive at 85 ºC and divided into three kingdoms. Though some are photosynthesis-capable, their type is not related to that of skyplanton.
    • Crustose - Colonize dust particles.
    • Midlevel autotrophic - Capable of photosynthesis with dimmer light.
    • Medusoid - Resemble airborne jellyfish.
  • Hyperthermophilia (hyperthermophiles) - Heterotrophs that thrive at 135 ºC, near or on the surface and sorted into 4 kingdoms.
    • Animal - They have internal digestion and sorted into 3 phyla.
      • Bilateral
      • Tetraradial
      • Worm-like
    • Fungoid - Multicellular fungi completely unrelated to skyfungi.
    • Poriferoid - Sponge-like organisms, such as the Tho'rahl'shothan.
    • Saprophyte - Tree and grass-like non-photosynthetic saprophytes.

The To'ul'hs belong to the tetraradial phylum inside the thermophylic animal kingdom, descending from sessile organisms not unlike an Earth crinoid.

Native species Edit

References Edit

  1. To'ul'h Prime. Encyclopedia Galactica. 22 July 2006.
  2. Giant-impact hypothesis. Wikipedia.
  3. First Plague, The (To'ul'h Prime). Encyclopedia Galactica. 8 August 2016.
  4. Reich, H. Rain's Dirty Little Secret. MinuteEarth. 8 May 2015.
  5. Thermostability. Wikipedia.
  6. To'ul'h Prime Phylogenetic Tree. Encyclopedia Galactica. 9 July 2014.

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