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Energy Emissions and Civilization Types
A classification system for civilisations observed outside the Terragen Sphere based on energy emission levels | |
.PNG) Image from The Astronomer, MiyuwiAuthor, adapted from an ESA image | |
| HEECs and MEECs in the Milky Way Galaxy | |
Ever since the Industrial Age, Terragens have sought to discover what biospheres and civilizations may exist beyond their physical reach by searching for biosignatures and technosignatures using ever more powerful telescopes. For millennia, the foremost tool for this purpose has been the Argus Array. With its extensive capabilities, details about many distant garden worlds and civilizations have been discovered. In addition, a few civilizations have sent transmissions meant to be decoded, using 'primers' of scientific and mathematical principles to establish the basics of communication and working their way to further complexity from there.
Civilizations are classified into four energy emission classes, based on what technosignatures are observable. Terms used in classification are based on level of technological advancement, not brightness - even a high-energy emission civilization is usually mostly or even completely undetectable with pre-Federation technology, and most were only gradually discovered and characterized over millennia. Each civilization is given a catalog number, which contains its emission class, the galaxy it is in, and the order of discovery in that galaxy, with a new number assigned if further study or changes in the civilization warrant moving it to a new class. Civilization class is also distinct from the toposophic level of the controlling beings in that civilization, which is usually not known with certainty, but lower limits can often be inferred based on observed technology and upper limits from its emission class (e.g. a low-emission civilization is too small to have archailects).
Civilizations are strongly concentrated in large galaxies, especially spiral galaxies. Small dwarf galaxies have a very low abundance of elements heavier than hydrogen and helium, lacking the necessary material to form planets and evolve life. As a result, civilizations are almost entirely absent from them.
The general characteristics and number of civilizations of each class discovered to date are as follows:
- High Energy Emission Civilization (HEEC): A HEEC exceeds K2 on the ancient Kardashev scale, consuming more than 1E26 watts of energy, and ranging in size from a single luminous star to tens of billions of stars, though larger ones are far rarer. There are 86 HEECs in Laniakea, 82 of which are the only examples in their respective galaxies, with only the Milky Way and one other galaxy hosting two HEECs each. Over 99% of large galaxies have no HEECs. The vast majority of visible HEECs, like other civilization classes, are not changing in size. However, a few are growing at various speeds while others are shrinking. Occasionally, HEECs are observed to suddenly stop growing, collapse, and/or even cease all emissions; such observations are of concern and the cause of much uncertainty among futurologically-minded Terragens, seemingly including at least some higher toposophics. The Terragens have been a HEEC since the Middle Federation Age.
- Medium Energy Emission Civilization (MEEC): A MEEC is above K1 on the Kardashev scale, using significantly more than 1E16 watts of energy, and may be as large as a K2. Most MEECs are limited to a single star system, or even a single, heavily developed world, but some do at least occasionally engage in interstellar travel. On average, a Milky Way-sized galaxy has about 9 MEECs, with the Milky Way itself hosting 12. MEECs undergo collapse more often than HEECs, but not nearly as often as lower-emission civilizations. A few MEECs, with time, may expand and become HEECs. The Terragens were a MEEC during the Solsys Golden Age and the early Federation era.
- Low Energy Emission Civilization (LEEC): A LEEC is at most K1, and is usually smaller, though it still emits at least some detectable electromagnetic technosignatures such as radio waves. LEECs are usually limited to a single planet, though some have outposts on other planets or even around other stars. Other LEECs span significant swaths of interstellar space, but make little use of the vast majority of the resources in their vicinity. A galaxy the size of the Milky Way is home to about 110 LEECs on average; the Milky Way itself has 131 of them. LEECs have a much higher risk of collapse than larger civilizations, although a few go on to become MEECs. A few have been observed to shrink their technosignature gradually, either due to a decrease in capability or size, or possibly to developing a Hider-like mentality. Terragens were a LEEC between the Industrial and Interplanetary Ages.
- Null Energy Emission Civilization (NEEC): NEECs emit no electromagnetic technosignatures, although their homeworld is often detectable as a garden world, and some alterations of the environment such as buildings may be observable. Most NEECs are primtech, though a few, such as the Silent Ones, are more advanced, but deliberately conceal themselves from the rest of the universe. Recent extrapolations by the Hamilton Institute of Exopaleontology, based on study of living and extinct xenosophonts and Argus Array surveys, indicate that a galaxy the size of the Milky Way has about 1,000 NEECs at any given time, of which nearly all will go extinct without ever developing electromagnetic technology. Similarly, the vast majority of garden worlds will never give rise to sophonts. Pre-Industrial Age humanity was a NEEC for all of the hundreds of thousands of years of its history.
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Development Notes
Text by ProxCenBound and The Astronomer
from an original article by Stephen Inniss and Steve Bowers
Initially published on 26 June 2006.
Revised 5 October 2024.
from an original article by Stephen Inniss and Steve Bowers
Initially published on 26 June 2006.
Revised 5 October 2024.
