Cauldron

(This world idea is for a sci-fi mod for some sort of civilization type game, hopefully one with multiple map abilities.  I'm not sure if this will happen, but have come up with some general ideas for the mechanics and worlds for it.)



General Description

Cauldron is about the size of earth, though is in orbit closer to its star.  It is similar in composition and mass, with some smallish moons nearby.  (One about pluto size, one about charon size.)  The tilt is about 10 degrees, with a day of about 17 hours.

The planet itself is named for its high temperatures, ranging from hot earth desert temperatures at the poles to higher than the boiling point of water near the equator.  Though not as hot as planets like Venus, the planet has its own dangers from radiation, a corrosive atmosphere and lakes, and large areas of active volcanoes.


Surface Features

From far away, Caldron has appears to have a system of continents and oceans, much like earth, although the oceans are somewhat smaller than those on earth.  The oceans are a mixture of Sulfuric acid and water, with small amounts of other dissolved materials, allowing the oceans to remain liquid under conditions that evaporate pure water.  The oceans themselves have large numbers of island arcs, some in long lines, some independent, though with larger islands on average than equivalents on earth.  Occasional spots of green and orange can be seem in the oceans, which appear to be clusters of acid dwelling bacteria that cluster in nutrient rich areas.

The continents, like earth's, have large regions of mountains and plains, although the mountains are mostly steeper and more jagged than comparable ones on earth.  These mountains have considerably more volcanoes than those seem on earth.  The terrain in these areas changes rapidly from year to year, as lava tunnels and channels continually form and collapse, explosive eruptions regularly coat and erode large areas, and the shifts in the ground can change the terrain on their own and trigger landslides.

On less mountainous areas, lava flows are still common, with volcanic "bulge provinces" often hosting lava fields and  their own ragged terrain.  Outside the volcanic areas, the terrain is filled with highly pulverized material, much like soil or sand.  In wetter areas, bacterial patches can be found, coloring the ground different shades of red, orange, and green.

The most unusual features on the continental plains are irridiated areas.  These area seem to be found on older, less eroded volcanic sites.  The radiation in these sites can get highly concentrated, enough in some areas to cause sicknesses in unshielded people, but is mostly more diffused, and more dangerous over time. Travel in these areas can be dangerous both due to radiation damgage, and to the ruggedness of the terrain, plus corrosion and electrical problems increased by radiation.


Atmosphere

The atmosphere of Cauldron is composed of Mostly nitrogen, with about 15% Carbon Dioxide, 10% oxygen, and small amounts of trace gases.  It has a pressure of about 1.5x that of earth's atmosphere.

Throughout the lower atmoshere, large patches of Sulfuric acid clouds block views of the surface, covering about 2/3 of the surface at a time.  Depending on weather patterns, the clouds may be composed of anything from pure acid to slightly acidic water.  In a few areas (With mediumly strong updrafts and large amounts of water), pure water or ice clouds appear high in the atmosphere.  Rain and Virga fall from these clouds, with virga more common underneath diluted clouds, high temperature areas, and low altitudes.

The winds on Caldron are slower, on average, than winds on earth, although the large scale patterns are similar.  On smaller scales, higher level acid clouds cool the surface significantly, resulting in constantly changing surface wind patterns.  The oceans and lakes themselves create winds as well, in a similar manner as earth.

Oceans/Rivers/Lakes

Similar to Earth's water system, the oceans on Cauldron are fed by a series of rivers and lakes, many starting in mountainous areas of the planet, ultimately fed by mainly by rain.   Depending on the weather, the fraction of sulfuric acid within small rivers can change significantly from day to day, with some drying up when too little sulfuric acid flows through them.  In general, higher altitude rivers are less acidic, both due to water evaporation at higher temperatures, and by being fed by rain with a higher percentage of water on average.

The water cycle of Cauldron works similarly to that of earth, with water evaporting mainly from oceans and lakes, feeding clouds, than raining out, and flowing back into surface water again.  However, far less life exists that can influence the cycle, and no water ice exists on Cauldron apart from a few very high clouds.

Sulfur operates on a much longer cycle on the planet.  Sulfur in the atmosphere mostly comes from Volcanoes, with a small amount coming from bacteria.  Once rained out, the sulfur is absorbed into rocks, and into the oceans, and subducted back to the interior to be erupted again.

Ocean currents operate on a similar system as on earth, with both a wind driven and temperature system in action.

Life

Some life does exist on cauldron, throughout most of the planet are high temperature, acid loving bacteria.  Clusters of such bacteria form on wetter areas of land, and in areas of the ocean with more concentrated nutrients.  Most of these bacteria are identified by color, with green, orange, and red the most common.

Photosynthetic bacteria, and eaters of photosynthetic bacteria, are the most common.  Most of these bacteria can photosynthesize carbon dioxide and water to oxygen and other material, as earth bacteria do, but use different chemical pathway so do so.  Volcanic energy is the next most common source of energy, with bacterial colonies commonly found near hydrothermal areas, and land based volcanoes.  Radiation serves as a source of energy for underground bacteria, and bacteria near irradiated areas,  but these areas are often dryer than other areas, usually limiting their growth.

Most oxygen in the atmiosphere is generated and used by bacteria.  Sulfur is also moved from one area to another by bacteria, with bacteria in dry areas generating acid to help conserve water, while bacteria in wet areas often use the acid as an oxidant, releasing sulfur dioxide to the air.

Explanation

(Disclaimer:  I am not in fact any sort of geologist, atmospheric scientist, planetary scientist, or anything related.  While I do occasionally attempt to read some papers, and more complex books, about planets for fun, I'm nowhere near an expert on any of this, and am making up these planets to have interesting characteristics, whether or not they would be be possible, and the resulting attempts at planets will read appropriately.  If any one of the above types of scientists is reading this and pulling their hair out, I understand completely.  :)  )

This world is being created to combine features of Venus and Io, as well as more generic "hot and dangerous" worlds (radioactive, barren deserts, volcanic, etc.)  The plan for the mod also leads to me wanting some sort of water like oceans on the planet.  This planet , along with Cryolith and Phobis Terra (will link to future posts), will be starting planets.  I'm planning on having sea technology, but in order to be useful on other planets, and still make sense, a water like ocean terrain will be needed (I figure a sulfuric acid/water mixture would need different materials, but would otherwise be similar enough to a water ocean so that the same technology and types of boats would make sense for both.)

The starting explanation for this planet's geology would be the planet having a much larger amount of radioactive elements than earth does.  This would lead to greater volcanic activity in general, and some of this activity I imagine as concentrating radioactive elements in particular areas.  (This is how I think pitchblende is formed, and a lot of ores seems to be formed this way, but is not something I know about in detail.)  The increased activity would also speed up tectonics, which I think would create less smooth terran.  The oceans would, though, give tectonics similar to earth.

The orbit I imagine would be farther out than venus's (I imagine these planets orbiting a sun like star), but still closer than earth, allowing the temperature to get higher while still sloowing the water/sulfuric acid mixture.  The increased volcanoes would put out more sulfur to form the clouds (based off of Venus mainly), and these clouds would help keep the planet cooler.  The sulfuric acid is also a way to allow water based oceans to exist on a hotter planet than otherwise would be the case.  Weather is something that feels harder to simulate or guess at in detail, so I've left the details vague.

The life is added mainly to make the planet more interesting.  Other characteristics, like the moons, magnetic field, or upper atmosphere, are things I'm not as sure of what might happen, so these I'm either making similar to earth, or just ignoring.