Grey goo

Grey goo, or gray goo, is a term first used by molecular nanotechnology pioneer Eric Drexler in his book Engines of Creation. The term refers to a hypothetical end-of-the-world event involving molecular nanotechnology in which out-of-control self-replicating robots consume all life on Earth while building more of themselves (a scenario known as ecophagy). It is usually used in a science fictional context. In a worst-case scenario, all of the matter in the universe could 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), killing the universe's residents. The disaster is posited to result from an accidental mutation in a self-replicating nanomachine used for other purposes, or possibly from a deliberate doomsday device.

Related Topics:
Eric Drexler - Engines of Creation - End-of-the-world - Molecular nanotechnology - Self-replicating - Earth - Ecophagy - Science fiction - Universe - Mutation - Doomsday device

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It is unclear whether the hypothetical molecular nanotechnology, if ever realized, 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 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 molecules, then it might even find itself being preyed upon by preexisting bacteria and other natural life forms. 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 grey goo in 4 billion years of evolution, it is unlikely that some artificial construct will manage to do so.

Related Topics:
Nanoparticles - Energy - Oxidised - Bacteria

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If nanorobots 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 (coal, for example) it's mostly well-oxidized and sitting in a free-energy minimum.

Related Topics:
Inorganic - Entropy - Coal - Free-energy

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Because of these limitations, grey goo might only be possible in an environment which lacks indigenous life to compete with it for resources. However, some proponents of molecular nanotechnology argue that artificial nanomachines might be able to outcompete natural life because they could have irreducibly complex designs that life could not have developed via natural evolution.

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Drexler has made a somewhat public effort to retract his gray goo hypothesis, in an effort to focus the debate on more realistic threats and misuses associated with knowledge-enabled nanoterrorism and other misuses.

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In Britain, the 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 29th July 2004.

Related Topics:
Britain - Prince of Wales - Royal Society - 29th July - 2004

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Recently, new analysis has shown that the danger of grey goo is far less likely than originally thought. However, other long-term major risks to society and the environment from nanotechnology have been identified.

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