CADRS Planetary Classification System, The

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Old Earth, classified as 161622CB76B3A329 on the CADRS scale

The Committee on Astronomical Data Reporting Standards of the Inter-Polity Commission on Metrological Standards has devised a classification system suitable for describing a variety of non-stellar objects in the Galaxy. This system, which is intended to supplement the more familiar Non-Luminous Worlds Classification System (NoLWoCS), is designed for use in various statistical analyses and in studies of comparative Planetology; it is particularly useful in computational planetology and the cataloging of astronomical objects.

The system consists of a 16 by 16 matrix of criteria and ranges of data, each criterion having a range of data that is labeled from 0 (meaning no data is available) to F (in most cases, being the uppermost given data point, though higher values are usually covered by F as well). The criteria are determined by the particular template used; the following criteria are used in Template 1.1510, Sub-Stellar Objects (as per CADRS Resolution 10589.7132-4(a), dated 23 Jung 10589 A.T.):

1: Is the object natural or artificial? (Objects which have been substantially modified are included in the artificial category*)
2: What is the object's period of revolution? (in years)
3: What is the eccentricity of the object's orbit around its primary?
4: What is the object's period of rotation? (in seconds)
5: What is the inclination of the object's orbit relative to the equator of its primary? (in degrees)
6: What is the distance, in radii, of the magnetosphere's "bow shock" from the object?
7: Of what is the object primarily composed?
8: What is the object's mass? (in kilograms)
9: What is the mean density of the object? (in kilograms per cubic meter)
10: What gas is predominant in the object's atmosphere?
11: What is the mean surface (or equivalent) atmospheric pressure of the object?
12: What is the oxidation ratio of a standard iron-57 redox test sample, as
measured by Mossbauer spectroscopy, after prolonged exposure to the object's
atmosphere at the surface (or equivalent)?
13: What fraction of the object's surface (or subsurface) is covered by liquid?
14: What molecule is predominant in the object's liquid zone?
15: What is the mean temperature at the object's surface (or equivalent)?
16: What fraction of the object's total mass is concentrated in a central core,
and is the object geologically active?

The full table of CADRS categories is listed on this web page.
This file can be downloaded here (.doc file)

Earth, as an example, is classified as 161622CB76B3A329.

This translates to: it is a naturally formed object with a period of revolution between 0.5674 and 3.153 years. It has an orbital eccentricity of between 0.0 and 0.076, a rotation period of between 3.704e+6 and 3.914e+7 seconds, and an orbital inclination between 6.43 and 12.86 degrees relative to the equator of its primary. Relative to its radius, the object's magnetospheric "bow shock", as measured at the substellar point, lies between 7.14 and 14.29 radii from the surface. The object is composed primarily of silicates, with a mass between 2.602e+23 and 1.194e+25 kg, and a mean density between 5329 and 6394 kg/m^3. Its atmosphere is primarily composed of nitrogen, with a mean surface pressure between 0.3455 and 14.25 bar. The ratio of Fe2+ to Fe3+, after prolonged contact with the atmosphere at the surface, is between 0.9286:0.0714 and 0.8571:0.1429, which indicates a moderately oxidizing environment. Between 64.29% and 71.43% of the object's surface is covered by liquid, in this case water. The object has a mean surface temperature of between 233.31 and 463.87 Kelvin. Finally, the object's central core represents 10% of the total mass and the object is geologically active.

Each description, if encoded as binary digits, is eight bytes in length; such a short length allows for the description to be repeated an arbitrary number of times within an individual Astronomical Data Report (which typically are several hundred megabytes in length) to ensure redundancy. Similarly, it is a relatively trivial task to compare large numbers of classifications derived from a particular template, as all data fields are fixed in length and placement. There also exist templates for stellar objects, black holes, galaxies, and various other types of objects found within the Known Universe.

*see CADRS addendum 55717 2 Faraday 10564 A.T for definition of 'substantial'
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Text by Radtech497
Initially published on 25 July 2013.