STAR ARMY

Sci-fi roleplaying and worldbuilding community

User Tools

Site Tools


guide:planets

Differences

This shows you the differences between two versions of the page.

Link to this comparison view

Both sides previous revisionPrevious revision
Next revisionBoth sides next revision
guide:planets [2018/02/12 22:56] – [Examples] frostjaegerguide:planets [2019/06/21 12:19] – Remove forced line breaks wes
Line 212: Line 212:
 ====== Star Army Guide to Types of Planets ====== ====== Star Army Guide to Types of Planets ======
 | :!: **The following article is currently NOT APPROVED for in-character usage.** | | :!: **The following article is currently NOT APPROVED for in-character usage.** |
-As seen on SARP's [[http://stararmy.com/setting/space/star_map_big.html|Star Map]], the Kikyo Sector has a wide variety of star systems, and those star systems have a wide variety of planets. Though every planet has its own unique properties, they can be grouped together into general types. This guide may also help to understand the star system creation guide, by describing the range of environments that might be generated using the Star System Calculator.\\+As seen on SARP's [[http://stararmy.com/setting/space/star_map_big.html|Star Map]], the Kikyo Sector has a wide variety of star systems, and those star systems have a wide variety of planets. Though every planet has its own unique properties, they can be grouped together into general types. This guide may also help to understand the star system creation guide, by describing the range of environments that might be generated using the Star System Calculator.
  
 The broadest way to classify planets is by their overall size. While size alone doesn't determine a planet's type, planets can be classified this way because their black body temperature, in conjunction with the planet's mass, determines the heaviest molecules the world can retain in its atmosphere. This means planets closer to their star, and orbiting brighter stars, might be more massive than colder planets that have been placed into a larger size category. The broadest way to classify planets is by their overall size. While size alone doesn't determine a planet's type, planets can be classified this way because their black body temperature, in conjunction with the planet's mass, determines the heaviest molecules the world can retain in its atmosphere. This means planets closer to their star, and orbiting brighter stars, might be more massive than colder planets that have been placed into a larger size category.
Line 218: Line 218:
 Since helium and hydrogen are the two most common elements in the universe, worlds that are large enough to retain helium usually, but not always, grow large enough to also retain hydrogen, and become gas giants. 'Standard' worlds are too small to retain helium, but still large enough to retain the all-essential water molecule. If they are in a star's habitable zone, they may have liquid-water oceans, a requirement for carbon-based life. Worlds somewhat smaller than this may still be able to retain dense nitrogen-based atmospheres, useful for exploration and terraforming. Smaller worlds never have significant atmosphere, and are only rarely of interest. Since helium and hydrogen are the two most common elements in the universe, worlds that are large enough to retain helium usually, but not always, grow large enough to also retain hydrogen, and become gas giants. 'Standard' worlds are too small to retain helium, but still large enough to retain the all-essential water molecule. If they are in a star's habitable zone, they may have liquid-water oceans, a requirement for carbon-based life. Worlds somewhat smaller than this may still be able to retain dense nitrogen-based atmospheres, useful for exploration and terraforming. Smaller worlds never have significant atmosphere, and are only rarely of interest.
  
-Gas giants themselves come in many sizes, from ten times the mass of a standard world to thousands of times that. Their moons are more likely to draw interest than the gas giant itself, though the radiation belts of gas giants can pose a significant hazard. The largest gas giants grow increasingly dense, eventually reaching the point where they ignite helium fusion in their cores, and become brown dwarf stars.\\  +Gas giants themselves come in many sizes, from ten times the mass of a standard world to thousands of times that. Their moons are more likely to draw interest than the gas giant itself, though the radiation belts of gas giants can pose a significant hazard. The largest gas giants grow increasingly dense, eventually reaching the point where they ignite helium fusion in their cores, and become brown dwarf stars.  
  
 === Units === === Units ===
-Before we can really talk in detail about exoplanets we need to have an understanding of units we use for  Density, Temperature, and Planetary Mass.\\ +Before we can really talk in detail about exoplanets we need to have an understanding of units we use for  Density, Temperature, and Planetary Mass. 
-The Average Density of a Planet is of course roughly a planets mass divided by the Approximate Volume it would have it it was a perfect sphere.  Density is measure either in units of kg/m^3 or g/cm^3.  One kg/m^3 equals 1000 g/cm^3.\\ +The Average Density of a Planet is of course roughly a planets mass divided by the Approximate Volume it would have it it was a perfect sphere.  Density is measure either in units of kg/m^3 or g/cm^3.  One kg/m^3 equals 1000 g/cm^3. 
-The Average Surface Temperature of a planet is measured in either degrees Celsius or degrees Kelvin.  The conversion from Celsius to Kelvin is simple as 0 C = 273.15 K.\\+The Average Surface Temperature of a planet is measured in either degrees Celsius or degrees Kelvin.  The conversion from Celsius to Kelvin is simple as 0 C = 273.15 K.
 The Planetary Mass like all masses is first and foremost measured in units of kilograms.  However, most planets then to have masses on order of 10^24 or 10^27, therefore to make thing more manageable, we use the units of [[wp>Earth_Mass]] (ME) and [[wp>Jupiter_mass]] (MJ),which are based on the Mass of Earth and Jupiter.  Generally Jupiter is 317.8 time more massive than Earth (1 MJ = 317.83 ME), so one normally uses Earth Mass for Terrestrial Planets and Jupiter Masses for Gas Giants.  Compared to the sun; however, Jupiter is very small, in fact 1 Sol or [[wp>Solar_Mass]] 1048 time 1 MJ. The Planetary Mass like all masses is first and foremost measured in units of kilograms.  However, most planets then to have masses on order of 10^24 or 10^27, therefore to make thing more manageable, we use the units of [[wp>Earth_Mass]] (ME) and [[wp>Jupiter_mass]] (MJ),which are based on the Mass of Earth and Jupiter.  Generally Jupiter is 317.8 time more massive than Earth (1 MJ = 317.83 ME), so one normally uses Earth Mass for Terrestrial Planets and Jupiter Masses for Gas Giants.  Compared to the sun; however, Jupiter is very small, in fact 1 Sol or [[wp>Solar_Mass]] 1048 time 1 MJ.
 The table below highlights conversions between various mass units The table below highlights conversions between various mass units
Line 246: Line 246:
   - planet with a silicon crust but completely lacking in a magnetic iron core, meaning it lack at magnetic field   - planet with a silicon crust but completely lacking in a magnetic iron core, meaning it lack at magnetic field
 === Coreless Lava Worlds === === Coreless Lava Worlds ===
-Examples: Venus\\+Examples: Venus
 === Coreless Rocky Deserts === === Coreless Rocky Deserts ===
-Examples: Moon and most other planet barren moons\\+Examples: Moon and most other planet barren moons
  
 ==== Habitable Earth-like Planets ==== ==== Habitable Earth-like Planets ====
-Examples: Earth\\ +Examples: Earth 
-Suggestions?\\+Suggestions?
  
  * [[planet:hanakos_world]]  * [[planet:hanakos_world]]
  
 === Forest Planets === === Forest Planets ===
-Suggestions?\\+Suggestions?
 === Swamp Planets === === Swamp Planets ===
-Suggestions?\\+Suggestions?
  
 ==== Ice Rock and Ice Planets ==== ==== Ice Rock and Ice Planets ====
Line 290: Line 290:
  
 [[wp>Ocean_planet]] [[wp>Ocean_planet]]
-Ocean planets; however, tend to cross over also more into other categories.  Except for a handful or silicon ocean planets that will be covered. Although Theoretically possible no carbon-silicate ocean worlds have been seen\\+Ocean planets; however, tend to cross over also more into other categories.  Except for a handful or silicon ocean planets that will be covered. Although Theoretically possible no carbon-silicate ocean worlds have been seen
  
 ==== General Ocean World ==== ==== General Ocean World ====
Line 309: Line 309:
 ^ **Semi-major Axis**^ > 1 AU ^ ^ **Semi-major Axis**^ > 1 AU ^
  
-Examples: Neptune and Uranus\\+Examples: Neptune and Uranus
 ===== Hot Neptune ===== ===== Hot Neptune =====
 ^ **Semi-major Axis**^ < 1 AU ^ ^ **Semi-major Axis**^ < 1 AU ^

guide/planets.txt · Last modified: 2023/12/20 18:20 by 127.0.0.1