Planetary Classification: Difference between revisions
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Natural characteristics of planets, such as age, mass and distance from their sun, place them in 20 naturally bounded classes which have been assigned an arbitrary alphabetic designation. | Natural characteristics of planets, such as age, mass and distance from their sun, place them in 20 naturally bounded classes which have been assigned an arbitrary alphabetic designation. | ||
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*'''Diameter:''' 10,000 - 50,000 km | *'''Diameter:''' 10,000 - 50,000 km | ||
*'''Location:''' Hot Zone / Ecosphere / Cold Zone | *'''Location:''' Hot Zone / Ecosphere / Cold Zone | ||
*'''Surface:''' Temperature can exceed | *'''Surface:''' Temperature can exceed 500ÿºK | ||
*'''Atmosphere:''' Turbulent, saturated with toxic chemicals and thermionic radiation | *'''Atmosphere:''' Turbulent, saturated with toxic chemicals and thermionic radiation | ||
*'''Evolution:''' n.a. | *'''Evolution:''' n.a. | ||
Revision as of 00:22, 16 March 2006
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Natural characteristics of planets, such as age, mass and distance from their sun, place them in 20 naturally bounded classes which have been assigned an arbitrary alphabetic designation. Location refers to the planet's relative distance from its primary star (Hot zone is closest, then Ecosphere, then Cold Zone). Depending on the star's magnitude and amount of energy it radiates, the distances of each zone from the star will vary. A planet's mass determines its internal heat generation and - in combination with its zone - its ability to hold an atmosphere. Some planets pass through distinct stages as they form and age, which may put them in separate classes. Evolution refers to the geological evolutionary process of the planetary body itself. It does not refer to life-form evolution. Class A Class A planets are small, typically 1 to 1/10 the mass of Earth, and are in their sun's cold zone. They are newly formed and their surfaces are still molten. Their atmospheres still retain many hydrogen compounds, as well as reactive gases and rock vapors. These planets will cool, becoming Class C.
Class B Class B planets are small, typically 1/10 the mass of Earth, and are in their sun's hot zone. Due to a combination of weak gravity and strong solar radiation, their atmospheres are very tenuous, with few chemically active gases, and their surfaces are extremely hot.
Class C Class C planets are small, typically 1 to 1/10 the mass of Earth and are in their sun's cold zone. Due to a combination of low solar radiation and little heat, their atmospheres are permanently frozen.
Class D Class D planets are small, typically 1 to 1/100 the mass of Earth, or less. Due to low gravity, they have lost their atmospheres. Their surfaces, directly exposed to radiation and meteor impact, are typically lifeless and heavily cratered.
Class E Class E planets are typically of about the mass of Earth and are in their sun's habitable zone. They are newly formed, and their surfaces are still molten. Their atmospheres still retain many hydrogen compounds, as well as reactive gases and rock vapors. These planets will cool, becoming Class F.
Class F Class F planets are typically about the mass of Earth and are in their sun's habitable zone. They are recently formed, and their surfaces are thin. Their atmospheres still contain some hydrogen compounds. These planets will cool further, becoming Class G.
Class G Class G planets are typically about the mass of Earth and are in their sun's habitable zone. They are younger than the Earth, and their surfaces are still crystallizing. Their atmospheres retain small amounts of toxic gases. As these planets continue cooling they may become other classes.
Class H Class H planets are typically about the mass of Earth and are in their sun's hot zone. Their gravity allows them to retain an atmosphere of heavy gases and metal vapors, but due to strong solar radiation, their surfaces are very hot.
Class I Class I planets (Gas Supergiants) are very large, typically 300 to 1,000 times the mass of Earth, and are their sun's cold zone. Low solar radiation and high gravity have allowed them to keep thick atmospheres of hydrogen compounds. High core temperatures cause them to radiate heat.
Class J Class J planets (Gas Giants) are large, typically 10 to 100 times the mass of Earth, and are in their sun's cold zone. Low solar radiation and high gravity have allowed them to keep thick atmospheres of hydrogen and hydrogen compounds.
Class K Class K planets are small, typically 1 to 1/10 the mass of Earth, and are in their sun's habitable zone. Due to weak gravity, their atmospheres are tenuous, but water is usually present.
Class L Class L planets are small, typically 1 to 1/10 the mass of Earth, and are in their sun's habitable zone. Their atmospheres are closer to breathable, and water is usually present if hard to find.
Class M Class M planets are typically about the mass of Earth and are in their sun's habitable zone. Their atmospheres contain significant oxygen, liquid water is a significant surface feature, and lifeforms are generally abundant. With more water they would be class N.
Class N Class N planets are typically of about the mass of Earth and are in their sun's habitable zone. Due to the greenhouse effect of dense atmospheres heavy in carbon dioxide, their surfaces are very hot and water is found in vapor form, if present at all.
Class O Class O planets are typically about the mass of the Earth and are in their sun's habitable zone. Their atmospheres contain significant oxygen, liquid water covers over 80 percent of the surface. Lifeforms are generally abundant. With less water they would be Class M.
Class P Class P planets are typically about the mass of the Earth and are in their sun's habitable zone. Their atmospheres contain significant oxygen, water ice covers over 80 percent of the surface. Lifeforms are generally rare, but resilient. With a higher temperature they could be Class M or O.
Class Q
Class R
Class S-T Class S and T planets (Gas Ultragiants) are very large, typically 10,000 times the mass of Earth, and are in their sun's cold zone. Low solar radiation and high gravity have allowed them to keep thick atmospheres of hydrogen and hydrogen compounds. High core temperatures cause them to radiate visible light. These are the largest possible planets, as more massive bodies generate enough core heat to initiate fusion reactions and become stars.
Class Y Class Y planets (Demon Class) are typically about the mass of earth and are in their sun's habitable zone. Their gravities are about Earth's. Their atmospheres are full of toxic gases, radiation, etc. Their atmospheres release spikes of thermeonic (ther-me-on-ick) radiation. The temperature on the planet is over 500 degrees Kelvin.
NOTE: All information above is taken from Geoffrey Mandel's "Star Trek Star Charts: The Complete Atlas of Star Trek" available from Pocket Books. |
