Part of a series of articles on |
Nanotechnology |
---|
Impact and applications |
Nanomaterials |
Molecular self-assembly |
Nanoelectronics |
Nanometrology |
Molecular nanotechnology |
Gray goo (also spelled as grey goo) is a hypothetical global catastrophic scenario involving molecular nanotechnology in which out-of-control self-replicating machines consume all biomass (and perhaps also everything else) on Earth while building many more of themselves, [1] [2] a scenario that has been called ecophagy (the literal consumption of the ecosystem). [3] The original idea assumed machines were designed to have this capability, while popularizations have assumed that machines might somehow gain this capability by accident.
Self-replicating machines of the macroscopic variety were originally described by mathematician John von Neumann, and are sometimes referred to as von Neumann machines or clanking replicators. The term gray goo was coined by nanotechnology pioneer K. Eric Drexler in his 1986 book Engines of Creation . [4] In 2004, he stated "I wish I had never used the term 'gray goo'." [5] Engines of Creation mentions "gray goo" as a thought experiment in two paragraphs and a note, while the popularized idea of gray goo was first publicized in a mass-circulation magazine, Omni , in November 1986. [6]
The term was first used by molecular nanotechnology pioneer K. Eric Drexler in Engines of Creation (1986). In Chapter 4, Engines Of Abundance, Drexler illustrates both exponential growth and inherent limits (not gray goo) by describing "dry" nanomachines that can function only if given special raw materials:
Imagine such a replicator floating in a bottle of chemicals, making copies of itself...the first replicator assembles a copy in one thousand seconds, the two replicators then build two more in the next thousand seconds, the four build another four, and the eight build another eight. At the end of ten hours, there are not thirty-six new replicators, but over 68 billion. In less than a day, they would weigh a ton; in less than two days, they would outweigh the Earth; in another four hours, they would exceed the mass of the Sun and all the planets combined — if the bottle of chemicals hadn't run dry long before.
According to Drexler, the term was popularized by an article in science fiction magazine Omni, which also popularized the term "nanotechnology" in the same issue. Drexler says arms control is a far greater issue than gray goo "nanobugs". [7]
Drexler describes gray goo in Chapter 11 of Engines of Creation:
Early assembler-based replicators could beat the most advanced modern organisms. 'Plants' with 'leaves' no more efficient than today's solar cells could out-compete real plants, crowding the biosphere with an inedible foliage. Tough, omnivorous 'bacteria' could out-compete real bacteria: they could spread like blowing pollen, replicate swiftly, and reduce the biosphere to dust in a matter of days. Dangerous replicators could easily be too tough, small, and rapidly spreading to stop — at least if we made no preparation. We have trouble enough controlling viruses and fruit flies.
Drexler notes that the geometric growth made possible by self-replication is inherently limited by the availability of suitable raw materials. Drexler used the term "gray goo" not to indicate color or texture, but to emphasize the difference between "superiority" in terms of human values and "superiority" in terms of competitive success:
Though masses of uncontrolled replicators need not be grey or gooey, the term "grey goo" emphasizes that replicators able to obliterate life might be less inspiring than a single species of crabgrass. They might be "superior" in an evolutionary sense, but this need not make them valuable.
Bill Joy, one of the founders of Sun Microsystems, discussed some of the problems with pursuing this technology in his now-famous 2000 article in Wired magazine, titled "Why The Future Doesn't Need Us". In direct response to Joy's concerns, the first quantitative technical analysis of the ecophagy scenario was published in 2000 by nanomedicine pioneer Robert Freitas. [3]
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: Molecular Machinery, Manufacturing, and Computation [8] describes manufacturing systems that are desktop-scale factories with specialized machines in fixed locations and conveyor belts to move parts from place to place. None of these measures would prevent a party from creating a weaponized gray goo, were such a thing possible.
King Charles III (then Prince of Wales) called upon the British Royal Society to investigate the "enormous environmental and social risks" of nanotechnology in a planned report, leading to much media commentary on gray goo. The Royal Society's report on nanoscience was released on 29 July 2004, and declared the possibility of self-replicating machines to lie too far in the future to be of concern to regulators. [9]
More recent analysis in the paper titled Safe Exponential Manufacturing from the Institute of Physics (co-written by Chris Phoenix, Director of Research of the Center for Responsible Nanotechnology, and Eric Drexler), shows that the danger of gray goo is far less likely than originally thought. [10] However, other long-term major risks to society and the environment from nanotechnology have been identified. [11] Drexler has made a somewhat public effort to retract his gray goo hypothesis, in an effort to focus the debate on more realistic threats associated with knowledge-enabled nanoterrorism and other misuses. [12]
In Safe Exponential Manufacturing, which was published in a 2004 issue of Nanotechnology, it was suggested that creating manufacturing systems with the ability to self-replicate by the use of their own energy sources would not be needed. [13] The Foresight Institute also recommended embedding controls in the molecular machines. These controls would be able to prevent anyone from purposely abusing nanotechnology, and therefore avoid the gray goo scenario. [14]
Gray goo is a useful construct for considering low-probability, high-impact outcomes from emerging technologies. Thus, it is a useful tool in the ethics of technology. Daniel A. Vallero applied it as a worst-case scenario thought experiment for technologists contemplating possible risks from advancing a technology. [15] This requires that a decision tree or event tree include even extremely low probability events if such events may have an extremely negative and irreversible consequence, i.e. application of the precautionary principle. Dianne Irving admonishes that "any error in science will have a rippling effect". [16] Vallero adapted this reference to chaos theory to emerging technologies, wherein slight permutations of initial conditions can lead to unforeseen and profoundly negative downstream effects, for which the technologist and the new technology's proponents must be held accountable.
The Foresight Institute (Foresight) is a San Francisco-based research non-profit that promotes the development of nanotechnology and other emerging technologies, such as safe AGI, biotech and longevity.
Kim Eric Drexler is an American engineer best known for introducing molecular nanotechnology (MNT), and his studies of its potential from the 1970s and 1980s. His 1991 doctoral thesis at Massachusetts Institute of Technology (MIT) was revised and published as the book Nanosystems: Molecular Machinery Manufacturing and Computation (1992), which received the Association of American Publishers award for Best Computer Science Book of 1992. He has been called the "godfather of nanotechnology".
Molecular nanotechnology (MNT) is a technology based on the ability to build structures to complex, atomic specifications by means of mechanosynthesis. This is distinct from nanoscale materials.
Nanotechnology is the manipulation of matter with at least one dimension sized from 1 to 100 nanometers (nm). At this scale, commonly known as the nanoscale, surface area and quantum mechanical effects become important in describing properties of matter. This definition of nanotechnology includes all types of research and technologies that deal with these special properties. It is common to see the plural form "nanotechnologies" as well as "nanoscale technologies" to refer to research and applications whose common trait is scale. An earlier understanding of nanotechnology referred to the particular technological goal of precisely manipulating atoms and molecules for fabricating macroscale products, now referred to as molecular nanotechnology.
Robert A. Freitas Jr. is an American nanotechnologist.
Ecophagy is a term coined by Robert Freitas that means the consumption of an ecosystem. It derives from Greek οἶκος (oikos) 'house, household' and φαγεῖν (phagein) 'to eat'.
A molecular assembler, as defined by K. Eric Drexler, is a "proposed device able to guide chemical reactions by positioning reactive molecules with atomic precision". A molecular assembler is a kind of molecular machine. Some biological molecules such as ribosomes fit this definition. This is because they receive instructions from messenger RNA and then assemble specific sequences of amino acids to construct protein molecules. However, the term "molecular assembler" usually refers to theoretical human-made devices.
Mechanosynthesis is a term for hypothetical chemical syntheses in which reaction outcomes are determined by the use of mechanical constraints to direct reactive molecules to specific molecular sites. There are presently no non-biological chemical syntheses which achieve this aim. Some atomic placement has been achieved with scanning tunnelling microscopes.
Engines of Creation: The Coming Era of Nanotechnology is a 1986 molecular nanotechnology book written by K. Eric Drexler with a foreword by Marvin Minsky. An updated version was released in 2007. The book has been translated into Japanese, French, Spanish, Italian, Russian, and Chinese.
Utility fog is a hypothetical collection of tiny nanobots that can replicate a physical structure. As such, it is a form of self-reconfiguring modular robotics.
A self-replicating machine is a type of autonomous robot that is capable of reproducing itself autonomously using raw materials found in the environment, thus exhibiting self-replication in a way analogous to that found in nature. The concept of self-replicating machines has been advanced and examined by Homer Jacobson, Edward F. Moore, Freeman Dyson, John von Neumann, Konrad Zuse and in more recent times by K. Eric Drexler in his book on nanotechnology, Engines of Creation and by Robert Freitas and Ralph Merkle in their review Kinematic Self-Replicating Machines which provided the first comprehensive analysis of the entire replicator design space. The future development of such technology is an integral part of several plans involving the mining of moons and asteroid belts for ore and other materials, the creation of lunar factories, and even the construction of solar power satellites in space. The von Neumann probe is one theoretical example of such a machine. Von Neumann also worked on what he called the universal constructor, a self-replicating machine that would be able to evolve and which he formalized in a cellular automata environment. Notably, Von Neumann's Self-Reproducing Automata scheme posited that open-ended evolution requires inherited information to be copied and passed to offspring separately from the self-replicating machine, an insight that preceded the discovery of the structure of the DNA molecule by Watson and Crick and how it is separately translated and replicated in the cell.
The use of nanotechnology in fiction has attracted scholarly attention. The first use of the distinguishing concepts of nanotechnology was "There's Plenty of Room at the Bottom", a talk given by physicist Richard Feynman in 1959. K. Eric Drexler's 1986 book Engines of Creation introduced the general public to the concept of nanotechnology. Since then, nanotechnology has been used frequently in a diverse range of fiction, often as a justification for unusual or far-fetched occurrences featured in speculative fiction.
The history of nanotechnology traces the development of the concepts and experimental work falling under the broad category of nanotechnology. Although nanotechnology is a relatively recent development in scientific research, the development of its central concepts happened over a longer period of time. The emergence of nanotechnology in the 1980s was caused by the convergence of experimental advances such as the invention of the scanning tunneling microscope in 1981 and the discovery of fullerenes in 1985, with the elucidation and popularization of a conceptual framework for the goals of nanotechnology beginning with the 1986 publication of the book Engines of Creation. The field was subject to growing public awareness and controversy in the early 2000s, with prominent debates about both its potential implications as well as the feasibility of the applications envisioned by advocates of molecular nanotechnology, and with governments moving to promote and fund research into nanotechnology. The early 2000s also saw the beginnings of commercial applications of nanotechnology, although these were limited to bulk applications of nanomaterials rather than the transformative applications envisioned by the field.
The Feynman Prize in Nanotechnology is an award given by the Foresight Institute for significant advances in nanotechnology. Two prizes are awarded annually, in the categories of experimental and theoretical work. There is also a separate challenge award for making a nanoscale robotic arm and 8-bit adder.
The following outline is provided as an overview of and topical guide to nanotechnology:
The societal impact of nanotechnology are the potential benefits and challenges that the introduction of novel nanotechnological devices and materials may hold for society and human interaction. The term is sometimes expanded to also include nanotechnology's health and environmental impact, but this article will only consider the social and political impact of nanotechnology.
Wet nanotechnology involves working up to large masses from small ones.
The Drexler–Smalley debate on molecular nanotechnology was a public dispute between K. Eric Drexler, the originator of the conceptual basis of molecular nanotechnology, and Richard Smalley, a recipient of the 1996 Nobel prize in Chemistry for the discovery of the nanomaterial buckminsterfullerene. The dispute was about the feasibility of constructing molecular assemblers, which are molecular machines which could robotically assemble molecular materials and devices by manipulating individual atoms or molecules. The concept of molecular assemblers was central to Drexler's conception of molecular nanotechnology, but Smalley argued that fundamental physical principles would prevent them from ever being possible. The two also traded accusations that the other's conception of nanotechnology was harmful to public perception of the field and threatened continued public support for nanotechnology research.
This glossary of nanotechnology is a list of definitions of terms and concepts relevant to nanotechnology, its sub-disciplines, and related fields.
Ethics of nanotechnology is the study of the ethical issues emerging from advances in nanotechnology and its impacts.