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Search For Non-Terragen Intelligence

Looking for signs of alien civilisation

Milky Way Civilisations (revised)
Image from The Astronomer, MiyuwiAuthor, adapted from an ESA image
The Milky Way holds two separate High Energy Emission Civilisations; very few galaxies have one such civilisation, let alone two.


The Initial Failure of Radio Detection

In 1959 c.e. (10 BT) Giuseppe Cocconi and Philip Morrison outlined the possibility of a determined Search for ExtraTerrestrial Intelligence, or SETI, using the instruments available at that time, and radio astronomer Frank Drake made the first search the next year. The noisy technosphere of Earth made detection of weak signals very difficult.

In 2009 CE (40 AT), the Kepler space observatory began to detect a very large number of exoplanets, including several Earth-sized objects. But at this time no more than a few erratic radio signals had been detected by Earth-based SETI searches, and these were attributed at the time to random noise and distorted transmissions of human origin. More recent analysis of this historical data suggests that some of these early signals may indeed have been of xenosophont origin, for instance intership relay communications of the type routinely intercepted in later years.

Before any interstellar probes were launched, the local stars had all been surveyed with enough resolution to detect a number of worlds which seemed to support a biosphere (the closest of which was in the Delta Pavonis system), and several candidates for terraforming. This gave a terrific spur to the colonisation movement, but still little evidence for data-bearing radio traffic had been found, although the search now covered the entire galaxy.

The first detection of an extraterrestrial technosignature was in 2230 c.e. (261 AT), by Julie Denley and a team of Space Adapted astronomers, using the PanTrojan Baseline between the L4 and L5 points of Jupiter. The artificial origin of the modulated laser signal coming from 14.7 million ly distant in the galaxy M83 was undeniable, although the data could not be decoded, and reoccurred only a few times over the next two hundred years before ceasing altogether.

This source (now known as Medium Energy Emission Civilisation MEEC-M83-1) has since been observed by more sensitive instruments and is still active, but seemingly no longer attempts to message distant civilizations, indicating that such programs are generally short-lived. MEEC-M83-1 was only detected because of such deliberate transmissions, but was not in itself a particularly high-energy civilisation. Despite its loss of interest in such messaging, it evidently is doing quite well in its local space, and may one day become a HEEC.

Before the Technocalypse several more technosignatures had been discovered, all more than 10,000 ly distant. The first within the Milky Way was in 340 AT, when the superbright astronomer Sam Mwiraria detected artificial infrared emissions from postulated megastructures in a small region of the galaxy about 12,700 ly distant, in the direction of Circinus. The Federation restarted the search, with the advantages of much longer baselines, and a better idea of the quality of emission expected from a distant civilisation by observing the various colonies as they developed. Soon this civilisation, today known as for classification purposes as MEEC-MW-1, had been mapped in some detail and the detected megastructures analysed. These structures are now known to be efficient Dyson swarms surrounding red dwarf stars, but other evidence for civilisation is largely absent, so this civilisation has been thought to be relatively isolationist in outlook, possibly an aioid civilisation like the Terragen Diamond Network. More recently, MEEC-MW-1 is thought to be the likely origin of the Trader ships, in contact with the Soft Ones.

Throughout the region known as the Terragen C-Horizon an increasing number of false detections of alien intelligence were occurring because of the independent spread of rogue artificially intelligent space probes. Entities aligned with the so-called Diamond Network and the Solipsist Panvirtuality often established themselves in systems well outside the reach of human colonisation efforts, and their emissions were often mistaken for alien civilisations until contact was made. When the first alien civilisation was finally contacted in 3831, expectations were once again proved wrong; after its unusual high CO2 ecology was detected by interferometry millennia before, To'ul'h had been a target for exploration, but the low-tech civilisation discovered there would never have been found from any great distance.

During this period several worlds were discovered which held relics of long-vanished civilisations, including a significant number of worlds which seemed to have been seeded artificially with complex life. Indeed, in many parts of the Terragen Sphere, worlds which had been modified by xenosophonts (or their agents) to support biospheres were somewhat more commonplace than life-bearing worlds that had evolved naturally.

So, by learning about the incredible diversity that intelligent life could take, the search became more accurate; such species as the Cthonids and the Ultimates were detected first by their emission characteristics, while others such as the Paulans, the Kammerer sentient forest and the Whisperweed were only found by close range survey of Gaian planets, all of which had been accurately surveyed at great distances without any detectable signs of intelligence. One very high technology civilisation restricted to a single solar system was only detected by close examination of their homeworld; the Silent Ones have become withdrawn and self-absorbed, using very secure communication channels which were indistinguishable from random noise to an observer. Such withdrawn species may be widespread but undetectable in the Milky Way galaxy and elsewhere.

Beyond the C-horizon

Using the thousand-light year baseline of the Argus Array, the Milky Way galaxy and the other members of the Local Group of galaxies have been comprehensively surveyed over the last seven thousand years. It is likely that all civilised intelligent species have been located except many of the well-hidden Null Energy Emission Civilisations (thought to make up nearly 90% of the total). The most spectacular results have been in the Triangulum Galaxy, assisted by an unsolicited data transmission giving many details of the society found there.

Within the Milky Way 13 medium emission civilisations have been found, all emitting energy somewhere between Kardashev Type I and II levels, comparable to the Solar System before the emergence of the Archailects. One of these, MEEC-MW-7, has shrunk over the millennia, and is now classified as LEEC-MW-153.

High Energy Emission Civilisations

The Milky Way is unusual in that it contains two separate High Energy Emission Civilisations; the Terragen Sphere, a rapidly expanding volume of colonisation originating in the Old Solar System, and a distant civilisation that appears to be spread in a ring around the galactic centre.

The civilisation HEEC-MW-1 has been observed in great detail but still retains many mysteries. See the entry in this article about civilisations observed in the Laniakea Supercluster.

A vast area of the galaxy in the Counterspinward direction seems to have no high or medium emission civilisation at all - this may be due to a depopulation event or a high civilisation now using advanced energy efficient technology such as reversible computation. Civilisations which do not emit detectable radiation are known as Null Energy Emission Civilisations, although some of these locations may be detectable as life-bearing worlds using telescopic observations.

The rest of the galaxy is outside our effective C-horizon; no light from the Terragen Sphere has reached them since the development of spaceflight. Unless (as is sometimes suspected) there exists a secret network of alien communication wormholes, the rest of the Universe is unaware of the existence of Humanity's mind children.

The following are dates at which Terragens are known to have first detected or discovered xenosophont civilizations by various methods.

Date

261 ATFirst unequivocal xenosophont technosignature detected (undecodable modulated laser signal in M83 14.7 million ly distant, by Julie Denley, using the PanTrojan Baseline; source eventually known as MEEC-M83-1)
1681 ATFirst artifact of an extinct xenosophont civilization discovered
3831 ATFirst direct contact (the To'ul'hs, by the MPA explorer transapient Fortunate Cloud)
5845 ATFirst intergalactic HEEC signal intended for reception (Triangulum Transmission, unsolicited)
7480 ATFirst detection of radio emissions leading to direct contact (Cthonids, by the Andian Mission)
10404 ATFirst extragalactic object/envoy (Semblance of Eternity; possibly a hoax)

 
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Appears in Topics
Alien Civilisations Outside the Terragen SphereSignificant Historical EventsXenology
Xenosophonts
 
Development Notes
Text by Steve Bowers, additions by Stephen Inniss
Initially published on 04 March 2003.

Further Reading

The G Infrared search for Extraterrestrial Civilisations with large energy supplies
The G Infrared search for Extraterrestrial Civilisations with large energy supplies Part Two
 
 
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