Help:Building planets and moons

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on a galactic scale

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Planets are often the basis for your civilization and species. Determining your star first will help evaluate the worlds you use and further explain the culture and society of the species that live there. Once complete, go through the following process to create a planet or moon.

Location Edit

The developer must follow a process to determine what the planet's overall statistics are and will need to be figured out for every planet in the system.

Although almost anything is possible, it should be considered that multiple naturally life-supporting planets in a system are relatively rare, because the planet must lie in the life zone of the star. To have life on other planets you can develop terraforming technology, biodomes or other cultural solutions.

The developer first decides where in the star system the planet is located. Generally, planets are identified by it's position from the primary/largest star in the system. The "scientific attribution" is StarName: Number (e.g. Earth would be Sol III). Then you can give the planet it's original name, known as the "common attribution."

Orbital radius Edit

Next determine the planet's Orbital Radius. This must be somewhat congruent with what position in the star system you chose. Keep the following life zones in mind if the planet must naturally support life.

Class Life Support (Centipars)
1.0 898,856.98 - 511,114.75
2.0 18,492,118 - 14,319,106
3.0 63,100 - 112,797

Radius and density Edit

The radius and density of your planet is completely arbitrary but you should keep in mind what is considered reasonable. For example, gaseous planets like Jupiter tend to be much bigger but not as dense as a planet with a crust and iron core. Following are the Basilicus Weights and Measures units for the Solar System to provide examples of actual figures.

Planet Radius ( SDU) Density ( SMU)
Mercury 1.5097E-59 0.00064798
Venus 3.7446E-59 0.0024954
Earth 3.9463E-59 0.0024127
Mars 2.1018E-59 0.0018153
Jupiter 4.4235E-58 0.00061121
Saturn 3.729E-58 0.0003171
Uranus 1.5814E-58 0.00059283
Neptune 1.5324E-58 0.00075368
Pluto 7.035E-60 0.0009329

Gravity Edit

Density is an arbitrary value, but choose it carefully because it directly contributes to your planet's gravitational pull. To figure out your planet's acceleration due to gravity you must complete a formula.

  1. Take the density of your planet and divide it by Earth's density (5.52 g/cm3)
  2. Take the above value and multiply it by the radius of your planet divided by the radius of Earth (6378.1 km)
  3. This is your gravitational pull relative to Earth, so multiply it by 176230 (the acceleration due to gravity on earth in MDU/STU2)
  4. You now have your planet's acceleration due to gravity in MDU/STU2.

Rotational and orbital period Edit

Rotational period is completely arbitrary and will determine how long the days are. Orbital Period, however, determines the year's length and is directly dependent upon the size of the orbit. Planets closer to the star will have shorter years than those farther away.

Axial tilt Edit

This is an arbitrary decision. However, it will dramatically affect the conditions of your planet. Take the following into account:

  • The Earth's axial tilt (23.4 degrees) allows for the seasons because there are periods of time throughout the year that a point on the planet is further or closer to the sun than it was before. If you want your planet to have seasons like Earth, the planet must be reasonably tilted (15-30 degrees).
  • A 0-degree (vertical) axis would mean there are no seasons and all parts of the world get the same amount of sunlight year round. It would still be warmer at the equator than at the poles due to the curvature of the planet. Note that an elliptical orbit would add some element of seasonality as the planet gets nearer or farther from the star.
  • On a 90-degree (horizontal) axis, each pole faces the star once a year during its respective summer solstice. One hemisphere would be in daylight for half the year (summer) while the other at night (winter). Clearly a planet like this would have extreme polar temperatures.

Moons Edit

You can have as many (or as few) moons as you like. The larger the planet the more likely there will be moons that its gravitational field has trapped, likewise a small planet will likely not have many if any moons at all. When creating moons be sure it is in the orbit it needs to prevent it from breaking apart and becoming a ring (the Roche Limit). You will need to choose a density of the moon(s) like you did with the planet first.

  1. Divide the density of your moon by the density of the planet
  2. Take the cubic root of that value
  3. Multiply that value by the radius of the planet
  4. Multiply that value by 2.423

That is how far away from the center of the planet the moon needs to be, and no less.

Work in progressEdit

Use the following template on your article to illustrate what needs to be done.

This is a task list for this article. When you have completed something that is listed to your satisfaction then type an "x" in between the brackets on the edit screen. If you find something that is not complete to your satisfaction and it is "checked", then remove the "x" within the bracket. If all tasks are complete, go ahead and delete this section.


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[ ] Region
[ ] Official Name
[ ] Indigenous Name
[ ] Flag/Banner
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[ ] Motto
[ ] Anthem
[ ] Capital
[ ] Largest Civilization
[ ] Official Language(s)
[ ] Government
[ ] Government Leader(s)
[ ] Star Class
[ ] Average Temperature
[ ] Planetary Classification
[ ] Orbital Radius
[ ] Acceleration Due to Gravity
[ ] Rotational Period
[ ] Orbital Period
[ ] Axial Tilt
[ ] Primary Atmospheric Composition
[ ] Escape Velocity
[ ] Natural Satellites
[ ] Stations
[ ] Planet Mass
[ ] Planet Radius
[ ] Planet Age
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