--Orbiting 886 million miles/1.4 billion kilometers from a vibrant main sequence star in an undisclosed corner of the Milky Way, boasting a bulk density of 1.88 g/cm3, primarily composed of water ice and rocky materials, a dense nitrogen-rich atmosphere of methane and ethane clouds and nitrogen-based smog, and a surface festooned by liquid hydrocarbon features, Terreno personifies the very definition of an alien world hosting life-forms not unlike any encountered on Earth--
Planetary Features
At 5,150 kilometers across with a bulk density of 1.88 g/cm3, Terreno is a relatively small planet composed primarily of water ice and rocky material with a dense, opaque atmosphere, which extends many kilometers above its surface. The planet is differentiated into several layers with a 3,400 kilometer rocky center encompassed by several layers composed of different crystal forms of ice. Though it boasts an extremely gelid surface, Terreno's interior is warm due to a liquid layer of magma consisting of water and ammonia between the ice crystal crust and deeper layers of high-pressure ice. Additionally, the presence of ammonia allows water to remain liquid in a subsurface ocean even at extremely low temperatures.
-Atmospheric Composition-
Possessing an atmospheric composition in the stratosphere containing 98.4% nitrogen with subtle traces of methane and hydrogen as well as ethane, diacetylene, methylacetylene, acetylene, propane, cyanoacetylene, hydrogen, carbon dioxide, carbon monoxide etc., the planet's wealth of hydrocarbons form in its upper atmosphere as a result of reactions from the breakup of methane by its star's ultraviolet light, producing a thick orange smog. In addition to sporting a surface pressure roughly 1.45 times that of Earth's and being nearly 1.20 times as massive as Earth's atmosphere, Terreno's atmosphere rotates much faster than its surface. Its opaque haze layers block most visible light from its home star and other sources, rendering its surface features obscure to any external observer.
If not for the presence of life on the planet, energy from its star would have converted all traces of methane in its atmosphere into more complex hydrocarbons. Though the primary source of methane in Terreno's atmosphere resides in its interior, released via eruptions from cyrovolcanoes (volcanoes that erupt methane). Additionally, its upper atmosphere contains polycyclic aromatic hydrocarbons.
-Climate-
As previously, Terreno is incredibly cold, possessing a surface temperature of -179 Celsius which causes the water ice on the planet to have extremely low vapor pressure, limiting the presence of water vapor to its stratosphere. Receiving very little light from its star, if not for the greenhouse effect on its surface from its atmospheric methane, Terreno would have been a much colder celestial domain. However, its atmospheric haze is counterproductive to this due to its anti-greenhouse effect which reflects starlight back into space, mitigating a portion of the greenhouse effect warming which renders its upper atmosphere significantly hotter than it's frigid surface.
Scattered and variable as they punctuate the overall atmospheric haze, the planet's clouds are composed primarily of methane, ethane as well as other simple organics. Periodically, liquid methane and other organic compounds rain onto its surface.
-Geological Features & Liquids-
Sporting a diverse geology with both rough and smooth areas, Terreno's surface flaunts a wide variety of features such as those that are volcanic in origin, disgorging an amalgamation of water and ammonia onto the surface. Windblown particles have caused streaky features that are hundreds of kilometers in length, while the few impact craters on its surface have been filled in by raining hydrocarbons. Marked by broad regions of bright and dark terrain, Terreno's surface is embellished by a prominent, reflective equatorial area of gargantuan physical dimensions filled with hills and cut by valleys and chasms.
Biological Cycle of Methane
With seas and lakes of ethane rich hydrocarbon, Terreno's surface temperature is between -88 Celsius and -183 Celsius as liquid ethane can only exist when subjected to such temperatures, and as a result, the evaporation process is weak. The ultraviolet radiation from the planet's star engenders complex photochemical reactions in the upper atmosphere by breaking the methane molecules into various compounds such as ethane or acetylene which combine with other molecules to form tholin (in essence, a red sludge). The ethane molecules formed in the upper atmosphere subsequently fall as rain in minuscule quantities.
Under these circumstances, an ecosystem based on methane exists on the planet. The solvent that enabled life to develop on Earth is water, while on Terreno it is liquid hydrocarbon. The living creatures have not developed on the basis of water or carbon dioxide since both molecules are frozen at the surface of the planet. The key compounds of life on Terreno are carbon, hydrogen, methane and ethane. Those elements or molecules are more flexible and more volatile than oxygen and water in the planet's harsh local climate conditions. The creatures absorb the hydrocarbon liquids and breathe the methane gas to produce the organic material and expire hydrogen. The planet's avian species for example, drink ethane rich hydrocarbon liquid, breathe hydrogen released by the planet's extraterrestrial vegetation and expire methane.
Extraterrestrial Life on Terreno
An understandably hostile sphere to the majority of organic life not adapted to its radical environment, Terreno while cold and lacking the atmospheric composition necessary to sustain Earth-based life-forms, is a welcoming haven to the organisms that have evolved to thrive in its exotic environment. Whereas on Earth it is liquid water that is the essential solvent from which life has emerged, on Terreno, contrary to the renown terrestrial planet, liquids of hydrocarbon (ethane, methane etc.), and ammonia are present at the surface, enabling the development of organic molecules, amino acids, proteins etc. Putting together the ingredients of this primitive soup, and the planet births the fundamental chemistry that has developed it's odd life-forms.
In the planet's early stages, its mixture of methane (CH4), ammonia (NH3) etc. was exposed to lightning in a process that led to the development of organic compounds and amino acids necessary for the creation of proteins. Like Earth, Terreno's atmosphere consists largely of nitrogen, however, oxygen is virtually nonexistent as it's life-forms neither breathe oxygen nor use it in feeding processes. As opposed to water, life on Terreno uses ethane or methane as a solvent and does not absorb oxygen or carbon dioxide as carbon dioxide on the planet is frozen and oxygen is an overt atmospheric rarity. Instead, living creatures on the planet absorb hydrocarbon gases such as methane and ethane and release hydrocarbon molecules or ammonia under the action of ultraviolet light that splits the molecules. With lakes and oceans of liquid hydrocarbon and glaciers of ammonia-rich ice from occasional ammonia-based snow, the planet's living species consist mostly of hydrocarbons.
Because of the planet's low gravity, its life-forms are relatively thin with thinner bones and less robust skeletal structures than those of the animals found on Earth. To sustain their own weight, they don't require powerful legs or paws, and the fish-like life-forms in bodies of liquid ethane or methane are lightweight as they move in a liquid of less density than water. Due the planet's low gravity and thick air, its avian species are heavier than those on Earth and their wings are shorter as a result of the cold environment. The denser air enables them to carry out fewer movements of the wings to advance at the same speed when compared to birds etc. on Earth. Because the energy from Terreno's star is too weak due to its distance from the luminous ball of plasma, the planet's life-forms are less pigmented than those on Earth. Additionally, in order to prosper in the planet's cryogenic temperatures, the life-forms on Terreno sport bodies made of highly resistant materials.
They are generally white or slightly red in color with a developed biological structure that enables them to store and manage the little energy they receive. As previously mentioned, the planet's avian species benefit greatly from its low gravity and dense air, enabling a smaller frequency in the movement of their wings so that they expend less energy during flight. The air however, is heavier and more difficult to displace.
-Subsurface Habitats-
Though liquid water does not exist on the surface, liquid water from a past impact has been preserved under a frozen isolation layer. There also exists a liquid-ammonia ocean deep below the planet's surface as well as an ammonia-water solution 200 kilometers deep beneath a water-ice crust with conditions that can sustain life as heat transfer between the interior and upper layers assists in sustaining the subsurface oceanic life.
Rules
- This planet is located in an unnamed (for now) planetary system in the Milky Way Galaxy.
- Anyone is welcome to show up and do whatever. If you want to take over areas of the planet etc. or want to do something prominent involving the planet, PM La_Espada.
- The purpose of the location thread is to help garner some interest in the nU expansion into space-related stuff that some of the other RPG'ers are doing.
- The level of technology, intelligence and stages in civilization of the alien life found on this planet is open to the interpretation of the RPG'ers that come here. You can have a primitive hunter-gatherer society in one corner of the planet and a highly advanced race of intellectuals in another corner.
- In case you weren't paying attention when you were reading the planet's description or if you didn't :P, this planet is completely inhospitable to your character if they evolved on Earth or an Earth-like planet and aren't physically invulnerable, have no need to breathe etc. so if you want to post here, sell the planet's atmospheric composition etc. by wearing some kind of airtight space-suit or erecting a force field or whatever, unless of course your character's body is made of material resistant enough that it won't crack at the cryogenic temperatures on the planet, among other things LOL.
- This one isn't so much a rule as it is a piece of advice. It rains liquid hydrocarbon on Terreno which is basically gasoline-like rain. The planet is like a giant candle waiting to be lit, but combustion needs oxygen and there's virtually no oxygen on the planet, so for you characters who will visit the planet wearing space suits with oxygen tanks, I advise you to be really really really really really careful with your characters' oxygen tanks or oxygen supply. If combustion does happen because perhaps you wanna go crazy ;P don't try and put out the fire with water, because the 'O' in H2O stands for oxygen.
- Have fun :)
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