Planetary Classification

Modifying Canon for the Modern World

Projects such as TRAPPIST and the Kepler Telescope have expanded our knowledge of the wide variety of potential planets. We have discovered worlds seldom considered by science before now: "Super-Earths," "Hot Jupiters," and "Ocean Worlds," we have come to understand are quite commonplace. We have also come to know that most stars likely have some planets, and that Type M and Type K stars are the most logical candidates for "Superhabitation"- long periods of habitability that will stretch into tens, even hundreds of billions of years. Reality has trumped some science theory as well- we are finding planets with orbits in binary star systems. Where science and science fiction seem farther apart (at least for now) is finding habitable planets around hot stars: A, B and O type stars. Here, Ulysses continues to take some creative license in the vein of Star Trek's model.

To try to keep up with this, the mods of the Ulysses sim decided to revamp Star Trek's traditional planetary classification system and try to expand it. There have been a few changes, and a little shuffling around. But we hope you will recognize the bones and features set forth by the franchise.

Planetary Classifications

A Chthonic Subtype

Class D (Dead, Dormant)

Lithogelidic Subtype

Lithogelidic Subtypes of Class D are mixes of rock, metals, and ices. Usually, they are undifferentiated (and therefore tend to be small). Lithogelidic bodies can differentiate their materials, but pressures within are not usually enough to alter the planet's structure to become Lithopelagic. Most Lithogelidic planets are similar to Earth's moon- regolith with surface ice hiding in crater shadows.

Lithopelagic Subtype

Lithopelagic subtypes of Class D planets are remarkably common. They tend to exist in the Goldilocks or Frost zone of a star. On the surface they appear very much like a Lithgelidic or standard Class D world. They may or may not have some surface ice. The difference between from Lithogelidic worlds and Lithopelagic worlds is this subtype has differentiated materials. Under a solid crust, increasing pressures have created liquid water "pockets" in the icy-rocky mantle.

Selenic Subtype

Sometimes called "Scam-Type" Class D's, Selenic subtypes lack metals, instead being dominated by metalloids and inorganic compounds (such as sulfur). They tend to be low mass and never had a core capable of generating a magnetic field. Selenic subtypes can be dangerous as Arsenic and Polonium are both toxic metalloids.

Undifferentiated Subtype

A Class E Planet

Class H (Harsh)

Class H worlds are generally habitable, at least in part, but have reduced resources or favorable elements compared to a Class M world. Harsh planets often lack water, have thin but breathable atmospheres, extremely turbulent and destructive weather, or else have wild temperature swings. Life can and does spring from such worlds, but tends to be hardy, homogeneous (alike) and located in the most habitable pockets of the planet. Because so many Class H worlds possess life forms and ecosystems already, they are seldom considered for terraformation. Class L and Class H worlds have some similarities, the criteria being that Class H worlds have pockets or zones of habitability whereas most Class L worlds are universally less conducive to humanoid life.

Class M (Minshara/Habitable)

Class M worlds, or Minshara in the Vulcan planetary classification system, are near-Earth like and generally habitable. However, they come in a wide variety of subtypes and compositions. The criteria for a Minshara class is that it must have a breathable atmosphere for baseline humanoid life, must have tolerable temperate zones conducive to plant and animal life, and must have liquid water to sustain biological life forms. Most Minshara class worlds exist in the "Goldilocks Zone" of a parent star, a swath of potential orbits that allow for liquid water.

A Calidic Subtype

Calidic Subtype

Calidic planets are hot for their classification and could be steaming jungles with saturated humidity, or baked deserts, yet they retain enough water and habitability to avoiding slipping into Class H or Class L status. Such worlds would be, by Earth standards, "Hothouse" or "Greenhouse" worlds.

Furenic Subtype

Furenic worlds of the Class M type are noted as having large, long-lasting and particularly powerful storm and wind events. Their atmospheres tend to be turbulent.

A Gelidic Subtype

Gelidic Subtype

Gelidic Class M Worlds are locked into persistently cooler temperatures, creating expanded continental and oceanic glaciation. While not yet a Class P "Snowball Earth," a Gelidic world is near-permanently in an "Ice Age."

Gracilic Subtype

Gracilic Class M worlds have thin but breathable atmospheres. They may have close-hugging atmospheres with sea-level like conditions that rapidly become unhabitable at higher terrains, or else sea-level atmosphere of the planet is similar to 3,000 meters above sea level on Earth.

Iugosic Subtype

Iugosic worlds have extremely mountainous terrain, often rapidly rising from any sea, ocean or lake. Such worlds tend to create varied "pocket climates" forming habitable valleys but have very little land at sea level. Iugosic worlds are almost always seismically and volcanically hyper-active. A large percentage of Iugosic worlds are geologically "young."

Lacustric Subtype

Lacustric Class M worlds have most of their surface water locked up in rivers, lakes, and inland seas. Such worlds have very few (if any) expansive oceans.

A Lutosic Subtype

Lutosic Subtype

Lutosic Class M worlds have thick atmospheres that usually obscure much of the planet's surface, and have increased air pressure. Often these worlds have dense and humid atmospheres. Habitability to a Human comfort level can likely be attained at a higher elevation. Lutosic subtypes may have plants, but those plants likely rely on a source of energy other than the sun. Lutosic worlds are also (usually) observed to have low light levels.

Paludal Subtype

A Paludal Subtype

Paludal Class M worlds are noted for having a high percentage of low-lying, near or at sea-level terrain which is often marshy or swampy. More than 75% of the planet's land is low-lying.

Pelagic Subtype

Pelagic Class M worlds are approaching Class O status and have surfaces dominated by oceans to a degree that 85% of the surface is under water.

Suptic/Cenotic Subtype

These unusual worlds possess Class M environments below the planet's surface- usually in extensive cavern systems. A great deal of the planet's water is subterranean but accessible in nature. The surface of such a world may or may not be condusive to life, but has a breathable atmosphere.

Tundric Subtype

Tundric Class M worlds are not Class P and are not Gelidic, but are prone to or in the process of entering an Ice Age.

Vadumic Subtype

Vadumic Class M worlds have unusually shallow oceans, often less than a kilometer deep, and at least 25% of the ocean is under less than 100m of water.

Xeric Subtype

Xeric subtypes of Class M planets are arid for the standard and have less surface water than traditional Minshara class. They are not yet defined as Class H.

Class O World

Class O (Oceanic)

Class O planets have all the elements conducive to life as most humanoids understand it. The main criteria for Class O status is that 85% or more of the planet is covered in water. Such worlds vary widely but otherwise meet Minshara requirements. Such worlds are different than Class W worlds- they are terrestrial worlds with rocky-metallic cores whereas Class W worlds are large bodies of differentiated liquids.

Furenic Subtype

Summavadumic Subtype

Summabathyian Subtype

Summabathyian world subtypes are 100% covered in water- no landmass breaks the water level. The depth of the "world ocean" is enough that the entire globe is "open sea:" the planet has extremely deep oceans that never allow land to come close to the surface. Such worlds do not have "shallow waters" and may possess ocean depths unseen on Earth- dozens of kilometers. However, Summabathyian worlds are still terrestrial and possess rocky surfaces- they are simply under a great deal of water.

Summapelagic Subtype

Summapelagic subtypes of the Class O worlds identifies a rocky, terrestrial body with 100% water cover- no landmass breaches the water level. Summapelagic worlds may have zones of relatively shallow, coastal waters.

Summavadumic Subtype

Summavadumic subtypes are terrestrial planets with 100% water cover, but the oceans tend to be quite shallow- less than a kilometer in depth. Though fully inundated, the planet may have regions that are under as little as a few meters of water and much of the planet is under less than 200 meters of water.

Tidal-Paludal Subtype

Tidal-Paludal planets are, for most of the time, covered in at least 85% ocean. However, external forces acting on the planet- a moon, a nearby gravitational body, a trojan world, or the Tidal-Paludal body being a moon itself- creates tidal forces that briefly expose large amounts of landmass (usually for a few hours). Conversely what little land it may have could be inundated by coastal waters as tides change for a similar period. Therefore, any above-ocean landmass on Tidal-Paludial worlds is tenuous and may be partially or completely submerged (or partially retreated from) according to the external factor causing the tides.

Ultrasalinated Subtype

Ultrasalinated Class O worlds are little different than other Class O planets on the surface. They are at least 85% covered in water. The unusual factor is that, below a certain ocean depth, the oceans become so salty that it forms a type of brine. Life finds increasingly alkaline waters too poisonous to exist in for long. Life that tries to enter such depths tend to enter a form of toxic shock. Some native life forms do evolve to exist in such environments.

Class T (Toxic)

Toxic worlds are not conducive to life as Humans and most humanoids understand it. They have geological or atmospheric chemistries that are hostile, harmful, or lethal to most known life forms. Life has been found on such worlds (such as atmospheric archaeobacteria on Venus) but it is seldom recognized as compatible with a life matrix Humans are a part of. Toxic worlds vary widely, classified by their compositional elements more than the features of their terrain. Class T worlds can be found in every orbital zone around a star, but begin life as terrestrial (rocky) bodies. They may have thick or thin atmospheres and may or may not have metallic cores enough to generate a magnetic field.