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Goo is a general term for replicators, especially but not exclusively small replicators, often with the implication of hazard from possible uncontrolled replication. A nanoswarm capable of spreading and growing, particularly if it has escaped its original parameters, is commonly referred to as goo. Originally the term was invented for neumann-capable (self-reproducing) nanobots, but at the modosophont level such devices are often quite fragile and typically cannot survive (or only survive for a limited time) outside of environments they are optimized for. In practice this may mean that that goo operations build in the expectation of constant replenishment or recycling of failed units or include the creation of a protective environment for the replicators. Such environments are analogous to bacterial biofilm and, in the case of micro and nanoscale systems, can have an appearance very similar to biological goo or slime. Despite this, goo as actually encountered and commonly described is a much broader term for swarms of devices or naturally evolved organisms that are capable of reproduction because of their internal nanoscale machinery. The most capable types of goo actually tend to be composed of units many orders of magnitude larger than nanobots.

Within the broad and loose parameters of the term, goo is typically distinguished by its origin, composition, or purpose. Types include Grey Goo (replicators focused primarily on converting matter into more of themselves), Khaki Goo (specifically military goo), Black Goo (disassembler goo, used to create feedstock for other processes, molecular and atom scale analysis, or sometimes as a weapon), Golden Goo (resource collecting goo), Green Goo (out of control biologicals or bionanotech devices), and many more. The most common defense against undesirable goo events is called Blue Goo. Without Blue Goo, controls and counters must be environmental.

Just like anything else that is neumann-capable, goo has environmental limits. Available materials (typically some limiting nutrient), ambient energy, thermodynamic considerations, and interference and competition between units are all factors that make even true grey goo a logistical threat, not an exponential one. In terms of direct physical measures against goo, hard radiation, temperatures outside its natural range, or substances that 'poison' its nanotech components may be employed. The most powerful (and dangerous) kinds of goo are able to adapt, either through simple Darwinian processes, complex programming, or both; this is one of the many reasons that a versatile (but suitably safe and controlled!) Blue Goo is often regarded as the standard for dealing with a goo infestation.

Replicator management has grown hugely in sophistication since the dawn of the Golden Age, and types other than preventive and unobtrusive Blue Goo are not often seen in the Civilized Galaxy. Nevertheless, exponential and explosive growth and the often innately chaotic processes of population dynamics are a potent combination, and mistakes do occur. The use of Neumann-capable devices is heavily regulated by law and tradition in most places, and new and experimental designs are often discouraged. Transapients are of course more adept at producing and controlling wide-ranging and highly adaptable replicators than ordinary sophonts, but even they sometimes commit errors.

Some use the word 'goo' in the loosest sense to refer to anything that spreads and replicates, especially if they believe it is a hazard or nuisance. 'Goo' in this sense is a relative term, and depends very much on who is using it. The ahuman and antihuman ais, have long regarded humans specifically, or embodied modosophonts generally, as a type of goo, and some of the most hostile Archailects in the antihuman category apparently regard any beings of any toposophic level below their own, except possibly those under their strict and complete control, as a goo infestation.

For safety reasons many kinds of swarm-tech do not carry the code for their construction inside themselves, but are manufactured by nanoforge or bioforge systems; swarms manufactured in this way are known as pastes. Other swarms are capable of self-replication, but only when supplied with the replication code from a remote location; this concept is known as Bicameral von Neumann Machine Architecture.

Commonly Referenced Goo Types:

Grey Goo:

Self-replicating nanotech devices that spread uncontrollably, building copies of themselves using all available material. Consists of a disassembler swarm (Black Goo) combined with assembler units programmed to create more Grey Goo. In practice, truly 'universal' Grey Goo is unknown, though there are some very versatile goo swarms, usually of transapient design, that can live on a wide range of materials in a wide variety of environmental conditions. Though the Grey Goo units of popular fiction are often the size of dust particles, actual Grey Goo is most effective when it includes a variety of sizes, from microscopic up to 'digester' units weighing hundreds of kilograms that break up materials for use by smaller units.

Truly accidental cases of Grey Goo are debatable; it may well be that most or even all Grey Goo incidents are intentional, and that behind apparent disasters there is some responsible hostile party who has simply not been identified.

Khaki Goo:

The military potential of self-replicating micro- and nanotechnology, popularly known as Khaki Goo, was imagined as far back as the Information Age, but not truly realised until the Federation Age, especially against soft targets (organic materials and unprotected infrastructure particularly). Early on, various treaties against the development or deployment of such weapons were enacted, but enforcing them, particularly over interstellar distances, was generally found to be impractical.

Early khaki goo was limited in its usefulness by various factors, such as the amount of stored energy each bot could carry and vulnerabilities that were relatively easy to exploit via various countermeasures. Later advancements overcame or bypassed many of these limitations, sometimes after multiple generations of technological improvement in both weapons and counter-measures.

Once established, goo infestations can be difficult to remove, particularly if they are programmed to lie dormant and/or attack vulnerable targets such as personnel, consumables, and data resources. On a planetary surface or the larger space habs, Khaki Goo is even more difficult to contain or remove; bionanotech Khaki Goo may hide in the local ecosystem, and drytech Khaki Goo may be disguised within the mechosystem.

The worst-case scenario is one in which a sufficiently sophisticated Khaki Goo weapon is deployed and results in the complete conversion of an ecosystem and/or mechosystem into suites of Goo units. This scenario has rarely happened in reality, one of the few cases being the destruction of Makintairas during the Second Consolidation War.

Blue Goo:

Defensive systems that are used as protection against adverse forms of goo such as Grey Goo, Khaki Goo, Golden Goo and so on; a mechosystem's equivalent to biological immune cells. The most powerful forms of Blue Goo have wide-ranging capabilities, can lie dormant in the form of spores throughout the environment they are meant to protect until a burgeoning threat triggers their activation, and can undergo explosive growth and hyperadaptation as the hazard they are designed to counter attempts to autoevolve around whatever countermeasures the Blue Goo is using. 'Blue Goo' is sometimes used to denote any form of benign and protective neumann-capable technology.

Black Goo:

Goo specifically designed to break down target materials into its molecular or atomic components with no intent of reconstruction into something else. This may be for the relatively benign purpose of creating feedstock, or it may be used in a hostile action. Applied outside of an industrial setting, Black Goo breaks down infrastructure and personnel, and may be part of a scorched earth policy. Where it can exploit a chemical gradient (for instance diamondoid or organic material in an oxygen-bearing atmosphere) Black Goo is particularly effective. Otherwise it is dependent on energy borne in the original units, and quickly 'runs out of steam' unless new energy is provided.

'Black Goo' is sometimes used, by analogy, as a descriptor for destructive social action, in particular disassembly and appropriation of the living spaces, tools, food, or permissions and rights of other beings.

Golden Goo:

A type of goo associated with resource collection and concentration. The name originates from an early Information Age hypothetical scenario in which self-replicating nanotech devices would be used to filter gold from seawater. Golden Goo is sometimes named instead for the substance or element it manipulates (thus Carbon Goo, Aluminium Goo, etc.).

Green Goo:
  1. A plague of bionanotech (non-drexlerian) or purely biological goo; especially of strong biotic form.
  2. Colloquial term for biological life spreading throughout the galaxy.
  3. In archaic usage, the scenario of nanomachines or bio-engineered organisms being used for human population control, either by governments or eco-terrorist groups, generally by sterilizing people with otherwise harmless infections.
Shadow Goo:

Goo that is hard to detect. This may be achieved in a variety of ways, some of which may be combined with one another. Shadow Goo may function at low concentrations and on small energy gradients. It might operate alongside or within other sorts of goo, it might disassemble once it has completed its function.

Emotive Goo:

Bionanotech / biomemetic replicators that use various methods such as pheromonal flooding and eidetic subliminals to incite different emotions or behaviors among any sapient bionts in the vicinity who have that capability. They may be spread using a variety of methods including transmission through air, water, some foodstuffs, and behaviour that results in exchange of bodily fluids.

Containment of Emotive Goo can be complicated by the fact that if the infection takes hold and spreads there may be whole societies or sub-cultures of individuals who strenuously reject attempts at being cured. Forced inoculation of these unwilling subjects may result in suicide, vandalism, or other dysfunctional forms of behaviour unless palliative psychoware is also employed. This is one of the aspects of mind-altering goo that distinguishes it from the other versions.The class as a whole is seen as a highly sophisticated descendant of the ancient Disinhibition Plagues of the Technocalypse.

Crude forms of Emotive Goo, some of them recreational, date back to the early Federation Age, and many designs have been developed since. Most currently active Emotive Goo is based around Dionysian Erotocracy, Zoeific, or Disarchy templates.

Pink Goo:

A curious disparaging term for the human species, in reference to the fact that it has spread out across the galaxy, replicating and filling available niches. There are two theories about this name. One is that it was invented by vec or aioid anti-biont chauvinists and has to do with the colour of the human interior (cf. 'Meatling') and the other is that the term was first invented by humans themselves on Old Earth in the First Century AT among a group of baselines who were particularly fair-skinned, especially as infants (so that babies would have been particularly pink). Either or both origins might be true.

Pink Goo is still sometimes used to refer to the Terragen Expansion as a whole, despite the fact that many individuals in the Terragen Sphere are not remotely human. It is also sometimes used by vecs and aioids to refer to bionts in general.

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Development Notes
Text by M. Alan Kazlev
amended & expanded by Anders Sandberg, Stephen Inniss, Steve Bowers, John B, Peter Kisner, updated by Todd Drashner
Initially published on 31 October 2001.

Revised 28 August 2015

Revised 19 October 2019