Introduction Being interested in science fiction, I like to dream up systems of planets that exist outside of our Solar System. It's interesting to imagine what kind of worlds might be out there, and inventing your own is a good way to express your ideas about alien planets. This is a process called "world-building", which can be used to construct realistic planets (if you follow known mathematical laws). I've taken the time to create computer-generated images of the planets that I have invented, so you can get a better feel for how they look. There is also a set of links at the bottom of this page that you can use to explore world-building from the perspective of other people, and maybe even create your own worlds.
The Peradis System My planetary system is based around Peradis, a white, main-sequence type star with the spectral type F5. It is both hotter and larger than the Sun. Peradis has a family of 7 planets, most of which are inhospitable to life as we know it. The names of these planets, in order from first to last, are Pyropheus, Temori, Aurumos, Sanada, Caretopas, Cyanos and Zenith. The images of the planets were generated in the Rhinoceros 3-D modeling program, whereas the surface views were generated in the Terragen program. The following is a detailed list of data about each planet. But first, I'll describe what each piece of data means (to those of you who are inexperienced in planet dynamics).
- Designation - This the systematic name of the planet. It is the combination of the parent star's name and the planet's order from that star. For example, the Earth's systematic name is Sol III. This is because it's star is Sol (another name for the Sun) and it is the 3rd planet from this star.
- Phaseotype - This is the classification of the planet according to my phaseotypic classification system, which I have explained here.
- Diameter - This is a measure of how wide the planet is, and is measured across the equator. No planet is perfectly spherical, so the diameter across the planet's equator will differ slightly from it's diameter as measured from its north pole to its south pole. Due to centrifugal force, the equator diameter will be slightly larger than the polar diameter.
- Gravity - This is the strength of the gravitational field of the planet in comparison to that of Earth (whose gravity equals 1.00 G).
- Rotational Period - This is the time it takes for the planet to make a complete rotation once. This is the also called the planet's "day".
- Orbital Period - This is the time it takes for the planet to travel around it's parent star once. This is also called the planet's "year".
- Average Orbital Distance - This is the average distance from the planet to its parent star. Since planets typically travel in egg-shaped or oval orbits, the distance from the planet to its star can vary quite a bit depending on its time of year. Thus, I use an average distance for simplicity.
- Average (Surface/Cloud-top) Temperature - For planets with discernable surfaces (usually terrestrial planets), this is a measure of the planet's average temperature at its surface. Since some planets don't have a discernable surface, such as gas giants, the average temperature is measured from the point in the planet's atmosphere where the pressure is equal to Earth's atmospheric pressure.
- Average Surface Pressure - This is a measure of how much pressure the planet's atmosphere exerts. It is measure in ATM, in which 1 ATM equals Earth's atmospheric pressure at sea level. For planets with very thin or nonexistent atmospheres, the pressure is not given but rather thought of as "negligible". For gas giants with huge atmospheric pressures, the pressure is given as "immense".
- Atmospheric Composition - This is the list of major chemicals that the planet's atmosphere contains.
- Hydrographics - This is the percentage of the planet's surface that is covered by liquid. This may constitute to seas, rivers, or even oceans. For reference, Earth's hydrographics are 70%. The chemical identity of the liquid is also given (in Earth's case it's water).
- Satellites - This is the number of satellites that the planet has. A satellite is a planet-like or asteroid-like object that orbits a planet.
Pyropheus
Designation Peradis I Phaseotype IIIa Diameter 18,426 miles Density 3.26 grams per cubic centimeter Gravity 1.37 G Rotational Period 18 hrs Orbital Period 96 Earth Days Average Orbital Distance 38 million miles Average Surface Temperature 3,141 degrees Fahrenheit Average Surface Pressure 21 ATM Atmospheric Composition H2 Hydrographics 100% (molten rock) Satellites 3 A turbulent planet with a surface hot enough to melt titanium, Pyropheus is inhospitable to any form of life. It's face is covered by a vast, all-consuming sea of molten rock, which constantly churns with convection currents. Because of the intense heat, the planet glows an eerie orange, which is slightly masked by its thick layer of dark clouds. Below its deep, searing ocean is a core made of solid iron. This core generates a magnetic field whose strength exceeds that of Earth's. With an active, unbreathable atmosphere, and metal-melting temperatures, Pyropheus is a planet that any astronaut would avoid.
Temori
Designation Peradis II Phaseotype IIIc Diameter 7,259 miles Density 5.36 grams per cubic centimeter Gravity 0.89 G Rotational Period 21 Hours Orbital Period 2.4 Earth Years Average Orbital Distance 168 million miles Average Surface Temperature 67 degrees Fahrenheit Average Surface Pressure 0.94 ATM Atmospheric Composition N2, O2, Kr Hydrographics 58% (water) Satellites 2 Relatively similar to the Earth in size and composition, Temori is an abode for life. Its lack of an axial tilt means that there are no seasons here, making its weather uniform year-round. Though it does not have as much water as the Earth, it still has plenty enough to power diverse ecosystems. Intelligent aliens, called the "serlisks" dwell here and have developed technology that exceeds our own. Although they call this planet home, they have ventured to other planets and solar systems. Temori has two moons, Baruna and Chassid. Chassid is quite small, but Baruna is larger than our own moon. It acts as a stabilizing device to keep Temori from wobbling in its orbit. More information on Temori is available here. Information on the aliens of Temori is available here.
Aurumos
Designation Peradis III Phaseotype IIc Diameter 9,042 miles Density 6.05 grams per cubic centimeter Gravity 1.25 G Rotational Period 1.33 Earth Days Orbital Period 3.8 Earth Years Average Orbital Distance 226 million miles Average Surface Temperature 30 degrees Fahrenheit Average Surface Pressure 1.33 ATM Atmospheric Composition N2, CO2 Hydrographics 0% Satellites 3 Deserts only make up a relatively small portion of Earth's climate. Not so for Aurumos. This entire planet could be likened to a giant, cold desert. Planetwide, Aurumos is dry as a bone and never receives rain. Thus, the sky is mostly cloudless, except for the occasional icy cirrus cloud. Although the atmospheric pressure and gravity are relatively tolerable by human standards, the lack of water and oxygen makes it a dangerous place to be. If any water were here, it would be frozen as ice during most parts of the year. It's 3 tiny moons are similar to asteroids.
Sanada
Sanada is the smallest of the major planets in the Peradis System, even smaller than our Moon. Because of its small size, the planet is incapable of holding any kind of appreciable atmosphere. Thus, it is left with a thin veil of gas that is slowly disappearing over time. Because of the lack of air, the planet has no weather and experiences no erosion. Therefore, landforms are changed little over time. There isn't much internal heat in the planet, so plate tectonics never produced large mountains. The most common features to disrupt the otherwise smooth surface of Sanada are craters, which come from occasional meteorite impacts. Its pinkish color is due to iron compounds present in surface rocks. The presence of iron may be used as a resource by a space-faring species, but Sanada has litte else to offer.
Designation Peradis IV Phaseotype IIc Diameter 1,985 miles Density 4.80 grams per cubic centimeter Gravity 0.22 G Rotational Period 7 Earth Days Orbital Period 4.8 Earth Years Average Orbital Distance 265 million miles Average Surface Temperature -60 degrees Fahrenheit Average Surface Pressure Negligible Atmospheric Composition CH4, H2 Hydrographics 0% Satellites 0
Caretopas
Perhaps similar to Uranus or Neptune, Caretopas has a thick, cloudy atmosphere. As one descends deeper into its dark atmosphere, it becomes increasingly thick and liquid-like. Deeper down, there is a large pressurized soup of an ocean composed of various chemicals, mostly methane, ammonia and water. In the center of Caretopas is a hot core of molten rock and metal, thus showing that the entire planet is fluid and in constant motion. The brown color of the planet is derived from various organic compounds and the trace gas nitrogen dioxide. Without a surface to land on, explorers would only be able to experience Caretopas by a quick fly-by mission.
Designation Peradis V Phaseotype IIId Diameter 29,069 miles Density 1.35 grams per cubic centimeter Gravity 0.90 G Rotational Period 21 hours Orbital Period 16.9 Earth Years Average Orbital Distance 610 million miles Average Cloud-top Temperature -98 degrees Fahrenheit Average Surface Pressure Immense Atmospheric Composition H2, He Hydrographics 100% (ammonia/methane/water) Satellites 7
Cyanos
A giant larger than Jupiter, Cyanos is the king of the Peradis System. It's enormous gravity has attracted a large family of moons, which it has more of than any other planet in the system. Like Jupiter, it has several layers: a fluctuating atmosphere, a thick region of liquid hydrogen, an underlying shell of liquid metallic hydrogen, and a core of molten rock. The presence of metallic hydrogen generates a whopper of a magnetic field, many times stronger than Earth's. Storms brew constantly in Cyanos' blue atmosphere, drawing their rotational energy from the planet's spin and internal heat. Slight traces of methane give the planet its characteristic azure color. As with Caretopas, not spaceship can land on Cyanos.
Designation Peradis VI Phaseotype IIId Diameter 91,337 miles Density 1.53 grams per cubic centimeter Gravity 3.19 G Rotational Period 12 hours Orbital Period 82 Earth Years Average Orbital Distance 1.75 billion miles Average Surface Temperature -250 degrees Fahrenheit Average Surface Pressure Immense Atmospheric Composition H2, He Hydrographics 100% (liquid hydrogen) Satellites 40
Zenith
Last, but not least, is the icy planet named Zenith. This planet is quite a bit larger than our ice planet, Pluto, and even has a relatively thick atmosphere. However, the very low temperature and slow rotational rate of Zenith prevent much prominent weather from taking place. Plate tectonics here are weak, but have produced some small mountains. Zenith is home to a relatively large assortment of moons, all of which are asteroid-like. In this respect, it is like Mars. The planet's crust is covered with snow and ice, most of which is frozen ammonia and water. Water ice could be potentially important for space pioneers who visit Zenith, as it could be harvested for drinking water and rocket fuel. However, since all of the water is frozen, no native life exists here.
Designation Peradis VII Phaseotype IIb Diameter 7,115 miles Density 3.65 grams per cubic centimeter Gravity 0.59 G Rotational Period 3.7 Earth Days Orbital Period 175 Earth Years Average Orbital Distance 2.9 billion miles Average Surface Temperature -326 degrees Fahrenheit Average Surface Pressure 0.45 ATM Atmospheric Composition H2, N2 Hydrographics 0% Satellites 5
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