Grey goo
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/* Grey goo in science fiction */ fixed links to recent dune ref addition
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'''''Grey goo''''' is a hypothetical end-of-the-world scenario involving [[molecular nanotechnology]] in which out-of-control [[self replication|self-replicating]] robots consume all living matter on [[Earth]] while building more of themselves – a scenario known as [[ecophagy]] (''eating the environment'').
The term ''grey goo'' is usually used in a [[science fiction]] or popular-press context. In the worst postulated scenarios (requiring large, space-capable machines), matter beyond Earth would also be turned into goo (with "goo" meaning a large mass of replicating nanomachines lacking large-scale structure, which may or may not actually appear goo-like). The disaster is posited to result from a deliberate [[doomsday device]], or from an accidental [[mutation]] in a self-replicating nanomachine used for other purposes, but designed to operate in a natural environment.
==Living goo==
One convenient analogy for the grey goo problem is to consider bacteria as the most perfect example of biological nanotechnology. As they have not reduced the world to living goo, some consider it unlikely that some artificial construct will manage to do so with grey goo.
The [[cell]] is the archetypal nanomachine and in fact does have many of the properties ascribed to grey goo, particularly, the ability to transform unstructured materials into copies of the replicating agent. Hence, the cell is able to incorporate [[carbon dioxide]], molecular [[nitrogen]] gas, and [[water]] into complex, multifunctional biomolecules, as well as incorporating solid materials such as [[hydroxyapatite]], and other calcium and phosphorus containing compounds. While certainly not the ecocatastrophe posited by grey goo alarmists, the transformative and contaminative nature of cells is impressive. Earth would certainly be a different place without the appearance of the cell (the most impressive of which would be the lack of an atmosphere containing large amounts of oxygen), and the possibility of seeding and contaminating the rest of the Solar System with cells is a real consideration when planning space missions.
Even so, some people argue that living goo, or even a combination of [[nanotechnology]] and [[biotechnology]] to create organic [[replicators]], is a more realistic threat than grey goo. Arguing that bacteria are ubiquitous and extraordinarily powerful, [[Bill Bryson]] (2003) says that the Earth is "their planet" and that we only exist on it because "they allow us to". Margulis and Sagan (1995) go further, arguing that all organisms, having descended from bacteria, ''are'' in a sense bacteria. Many kinds of bacteria are in fact essential for human life and are found in large quantities in the human digestive tract, in a [[symbiotic relationship]].
Thus a living goo could be a [[multicellular organism]] that obtains its raw materials to grow through [[ecophagy]], and then grows through a process of exponential assembly such as [[cell division]].{{Or|date=November 2007}}
A more literal biological analogy to grey goo are [[prions]], which have been implicated in such diseases as [[kuru]], [[Mad Cow disease]], [[Creutzfeldt-Jakob disease]], and [[fatal familial insomnia]]. In all of these conditions, an abnormal protein possesses the ability to unfold and refold other normally functioning proteins into copies of itself. Prions are extraordinarily contagious and difficult to destroy, but their relatively sluggish rate of transformation has prevented them from successfully overrunning the biosphere.
==Risks and precautions==
It is unclear whether the molecular nanotechnology would be capable of creating grey goo at all. Among other common refutations, theorists suggest that the very size of [[nanoparticles]] inhibits them from moving very quickly. While the biological matter that composes life releases significant amounts of [[energy]] when [[oxidisation|oxidised]], and other sources of energy such as sunlight are available, this energy might not be sufficient for the putative nanorobots to out-compete existing organic [[life]] that already uses those resources, especially considering how much energy nanorobots would use for locomotion. If the nanomachine was itself composed of [[organic molecule]]s, then it might even find itself being preyed upon by preexisting bacteria and other natural life forms.
If self-replicating machines were built of [[inorganic]] compounds or made much use of elements that are not generally found in living matter, then they would need to use much of their metabolic output for fighting [[entropy]] as they purified (reduce sand to silicon, for instance) and synthesized the necessary building blocks. There would be little chemical energy available from inorganic matter such as rocks because, aside from a few exceptions it is mostly well-oxidized and sitting in a [[Thermodynamic free energy|free-energy]] minimum.
Assuming a molecular nanotechnological [[replicator]] were capable of causing a grey goo disaster, safety precautions might include programming them to stop reproducing after a certain number of [[generation]]s (see [[cancer]]), designing them to require a rare material that would be sprayed on the construction site before their release, or requiring constant direct control from an external computer. Another possibility is to [[encrypt]] the memory of the replicators in such a way that any changed copy would [[decrypt]] to a meaningless, random bit string.
Drexler more recently conceded that there is no need to build anything that even resembles a potential runaway replicator. This would avoid the problem entirely. In a paper in the journal ''Nanotechnology,'' he argues that self-replicating machines are needlessly complex and inefficient. His 1992 technical book on advanced nanotechnologies [[Nanosystems|''Nanosystems: Molecular Machinery, Manufacturing, and Computation'']] [http://www.e-drexler.com/d/06/00/Nanosystems/toc.html] describes manufacturing systems that are desktop-scale factories with specialized machines in fixed locations and conveyor belts to move parts from place to place. Popular culture, however, remains focused on imagined scenarios derived from his older ideas. None of these measures would prevent a party creating a weaponised grey goo, were such a thing possible.
Oxford based philosopher [[Nick Bostrom]] discusses the idea of a future powerful [[superintelligence]], and the risks that we/it face should it attempt to gain atomic level control of matter.
In [[United Kingdom|Britain]], the [[Charles, Prince of Wales|Prince of Wales]] called upon the [[Royal Society]] to investigate the "enormous environmental and social risks" of nanotechnology in a planned report, leading to much delighted media commentary on grey goo. The Royal Society's report on nanoscience was released on [[29 July]] [[2004]], and dismisses the idea as impossible.
More recent analysis has shown that the danger of grey goo is far less likely than originally thought.<ref>{{cite press release| url=http://www.crnano.org/PR-IOP.htm| date=June 9, 2004| title=Leading nanotech experts put 'grey goo' in perspective| publisher=Center for Responsible Nanotechnology| accessdate=2006-06-17}}</ref> However, other long-term major risks to society and the environment from nanotechnology have been identified.<ref>{{cite web
| url=http://www.crnano.org/dangers.htm| title= Current Results of Our Research| publisher=Center for Responsible Nanotechnology| accessdate=2006-06-17}}</ref> Drexler has made a somewhat public effort to retract his grey goo hypothesis, in an effort to focus the debate on more realistic threats associated with knowledge-enabled [[nanoterrorism]] and other misuses.
==Famous quotes==
* "We cannot afford certain types of accidents", Eric Drexler, ''[[Engines of creation]]'', 1986
* "I wish I had never used the term 'grey goo'", Eric Drexler, ''[[Nature (journal)|Nature]]'', [[10 June]] [[2004]]
==Grey goo in science fiction==
* In Frank Herbert's Dune series, a weapon is being researched at one point which would be 'a self improving thing which would seek out life and reduce that life to its inorganic matter.' Though not nanotechnological in nature, the autonomous but unthinking threat is similar. <ref>"At one time... [...] The lxians contemplated making a weapon-a type of hunter-seeker, self-propelled death with a machine mind. It was to be designed as a self improving thing which would seek out life and reduce that life to its inorganic matter. [...] The lxians do not recognize that machine makers always run the risk of becoming totally machine. This is ultimate sterility. Machines always fail... given time. And when these machines failed there would be nothing left, no life at all." - [[Frank Herbert]], [[God Emperor of Dune]] (1981)</ref>
* In [[Ray Kurzweil]]'s film ''[[The Singularity Is Near]]'', a computer avatar called Ramona discovers that some nanorobots could destroy the world if not stopped.
* In [[Wil McCarthy]]'s sci-fi novel ''[[Bloom (novel)|Bloom]]'', Earth’s ecosystem is destroyed within hours by a grey goo, annihilating all biological [[life]]. The grey goo then develops its own unique “ecosystem”. The only [[human]] survivors are colonists who flee to the outer solar system. The book's protagonists come from [[Jupiter]]’s [[moon]] [[Ganymede (moon)|Ganymede]].<ref> McCarthy, Will ''Bloom'' New York:1998—Ballantine Del Rey Books </ref>
* Although not strictly speaking science fiction, [[Jasper Fforde]]'s ''[[Lost in a Good Book]]'' features a narrowly-averted apocalypse in which all biological life in the world is converted into "Dream Topping" (a whipped cream-like substance) by overenthusiastic [[nanomachines]].
* In the intro to the video game ''[[Deus Ex: Invisible War]]'', a villain uses a ''nanite detonator'', wiping out the entire city of [[Chicago]] with a goo-like substance that seems to freeze/destabilize anything it comes into contact with.
* Self-reproducing nanorobots were heavily featured in Michael Crichton's novel ''[[Prey (novel)|Prey]]''.
* In [[Greg Bear]]'s novel ''[[Blood Music]]'', simple biological computers evolve to become self-aware 'noocytes', which assimilate most of the biosphere of North America before abandoning the normal plane of existence.
* In ''[[Universe at War: Earth Assault]]'', Novus uses a megaweapon called the grey mass launcher, which turns a territory in global mode into a "grey mass".
* [[Smoke (Mortal Kombat)|Smoke's]] ending in ''[[Mortal Kombat Armageddon]]'' describes grey goo consuming the realm of Edenia.
* In [[Walter Jon Williams]]' novel ''[[Aristoi (novel)|Aristoi]]'', Earth was destroyed by gray goo (codenamed "Mataglap") and it is used to destroy an asteroid installation owned by the protagonist.
* In the made-for-TV film ''[[Path of Destruction (film)|Path of Destruction]]'', accidentally released grey goo causes weather problems.
* In [[John Robert Marlow]]'s novel ''[[Nano (novel)|Nano]]'', the invention of self-replicating nanites results in a team of assassins hired by the government on the hunt for a scientist and reporter, nearly ending in the destruction of San Francisco by "incorrectly programmed" grey goo.
* In [[Gargoyles (TV series)|''Gargoyles'']] episode Walkabout, a sentient nanite swarm called "The Matrix" is confronted in the Australian outback.
*In the book ''[[Specials]]'' by [[Scott Westerfeld]] the characters [[Tally Youngblood]] and [[Shay]] use grey goo to break out of the armory in [[New Pretty Town]].
* In ''[[Moonseed_(novel)|Moonseed]]'', the 1998 book by [[Stephen Baxter]], the Earth is consumed by a grey goo-type substance inadvertantly imported from the Moon.
* In the game ''[[Supreme Commander]]'' by [[THQ]] and Gas-Powered Games, the Aeon Illuminate uses a grey goo material to construct all of their buildings and units. The commander shoots a puddle onto the ground and then it starts to rise and shape into the desired object.
* In the game ''[[Outpost 2]]'', the faction of Eden is expirementing on a way to terraform the new planet they have settled to support life. Suddenly the experiment goes horribly wrong and a nanotechnology/terraforming virus is released, eventually taking over the planet and causing the survivors to work together in order to build a new spacecraft to leave the planet to find a new one.
== See also ==
* [[Clanking replicator]] (often called [[John von Neumann|von Neumann]] machine)
* [[Culture shock]]
* [[Ice-9]]
* [[Midas|Midas touch]]
* [[Precautionary principle]]
* [[Self-replicating spacecraft]]
* [[Technology assessment]]
==References==
{{reflist}}
==Further reading==
<div class="references-small">
*[[Lynn Margulis]] and [[Dorion Sagan]] - ''What is Life?'' (1995). Simon & Schuster. ISBN 0-684-81087-5
*Bill Bryson ''[[A Short History of Nearly Everything]]'' (2003)
*[http://www.archive.org/details/NickSzabosEssayGreenGoo-LifeInTheEraOfHumaneGenocide Green Goo - Life In The Era Of Humane Genocide] by Nick Szabo
*[http://www.etcgroup.org/upload/publication/174/01/comm_greengoo77.pdf Green Goo: Nanotechnology Comes Alive!]
*[http://www.wired.com/news/medtech/0,1286,64235,00.html?tw=wn_tophead_5 Green Goo: The New Nanothreat] from Wired</div>
== External links ==
* [http://lifeboat.com/ex/global.ecophagy Some Limits to Global Ecophagy by Biovorous Nanoreplicators, with Public Policy Recommendations]
* [http://www.iop.org/EJ/news/-topic=763/journal/0957-4484 Nanotechnology pioneer slays “grey goo” myths] Paper critical of "grey goo"
* [http://www.nanotec.org.uk/finalReport.htm Online edition of the Royal Society's report ''Nanoscience and nanotechnologies: opportunities and uncertainties'']
* [http://www.nanotech-now.com/goo.htm Goo and Paste Directory]
* [http://www.nanotec.org.uk/ UK Government & Royal Society commission on Nanotechnology and Nanoscience]
[[Category:Nanotechnology]]
[[Category:Artificial life]]
[[Category:Environmental disasters]]
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