Misplaced Pages

Molecular assembler: Difference between revisions

Article snapshot taken from Wikipedia with creative commons attribution-sharealike license. Give it a read and then ask your questions in the chat. We can research this topic together.
Browse history interactively← Previous editNext edit →Content deleted Content addedVisualWikitext
Revision as of 18:12, 14 March 2007 edit68.0.120.35 (talk) +safety guidelines← Previous edit Revision as of 17:33, 21 March 2007 edit undoBetacommand (talk | contribs)86,927 editsm removing inappropriate link per WP:EL, WP:SPAM, WP:RS, and WP:NOTNext edit →
Line 65: Line 65:
* *
* article originally in Wired * article originally in Wired
* discussion on assembler risk
* UK EducationGuardian, ] ] * UK EducationGuardian, ] ]
* *

Revision as of 17:33, 21 March 2007

A molecular assembler as defined by K. Eric Drexler are "proposed devices able to guide chemical reactions by positioning reactive molecules with atomic precision." Although he also introduced a related term "molecular manufacturing" which he defined as the programmed "chemical synthesis of complex structures by mechanically positioning reactive molecules, not by manipulating individual atoms." Some biological molecules such as ribosomes fit this definition, since while working within a cell's environment, it receives instructions from mRNA and then assembles specific sequences of amino acids to construct protein molecules. However, the term "molecular assembler" usually refers to theoretical man-made or synthetic devices. They are thought to be highly desirable since they have been theorized to manufacture products with absolute precision and thus without any pollution. However, others have warned that the such a powerful technology might get out of control and begin to compete with natural forms of life on earth.

Since synthetic assemblers have never been constructed a lot of controversy exists as to whether they are possible or simply science fiction. Confusion and controversy has also stemmed from their classification as nanotechnology, which is a broadly defined terminology. Nanotechnology is an active area of research which has already been applied to the production of real products; however there are currently no research efforts into the actual construction of "molecular assemblers". A primary criticism of the computational research into "molecular assemblers" is that the structures investigated are thought to be impossible to synthesize. Much as only certain programs can be written for the universal computer, only certain configurations can be constructed with universal assemblers.

Production through self replication

The nanoscale size of a typical science fiction universal molecular assembler requires an extremely large number of such devices in order to produce a practical quantity of a desired product. However, if one were able to construct a single such molecular assembler then it might be programmed to self-replicate, constructing many copies of itself, allowing an exponential rate of production. Then after sufficient quantities of the molecular assemblers were available, they would then be re-programmed for production of the desired product. However, if self-replication of molecular assemblers were not restrained then it might lead to competition with naturally occurring organisms. This has been called the grey goo problem.

Drexler and Smalley debate

A major influence in the discussion of molecular assemblers is K. Eric Drexler founder of the Foresight Institute, who has advocated the position that the introduction of molecular assemblers would transform the world in his book "Engines of Creation: The Coming Era of Nanotechnology," He believes that they would be capable of building anything allowed by the laws that govern the universe with absolute precision and thus without any pollution. He has also stressed that there are great potential dangers from such technology, such as the destruction of life on earth. He asserts that such general assemblers are inevitable and that we need to develop protocols to ensure that their implementation remains benevolent.

Since artificial molecular assemblers remain strictly theoretical Drexler’s position is quite controversial. One of the most outspoken critics of Drexler’s futuristic vision of molecular assemblers is Professor Richard Smalley who won the Nobel prize for his contributions to the field of nanotechnology. Smalley believes that such assemblers are not physically possible and introduced scientific objections to them. One of his main objections he has termed the “fat fingers problem" and the "sticky fingers problem” that he believes excludes the possibility of precision picking and placing of individual atoms. He also believes that Drexler’s speculations about apocalyptic dangers of molecular assemblers threaten the public support for development of nanotechnology.

To address the debate between Drexler and Smalley regarding molecular assemblers Chemical & Engineering News published a point-counterpoint consisting of an exchange of letters that addressed the issues.

Influence on the regulation of nanotechnology

Speculation on the power of artificial molecular assemblers has sparked a wider political discussion on the implication of nanotechnology. This is in part due to the fact that nanotechnology is a very broad term and could include “molecular assemblers.” Discussion of the possible implications of fantastic molecular assemblers has prompted calls for regulation of current and future nanotechnology. There are very real concerns with the potential health and ecological impact of nanotechnology that is being integrated in manufactured products. Greenpeace for instance commissioned a report concerning nanotechnology in which they express concern into the toxicity of nanomaterials that have been introduced in the environment. However, it makes only passing references to “assembler” technology. The UK Royal Society and UK Royal Academy of Engineering also commissioned a report entitled “Nanoscience and nanotechnologies: opportunities and uncertainties” regarding the larger social and ecological implications on nanotechnology. This report does not discuss the threat posed by potential “molecular assemblers.”

Grey Goo controversy

Speculation about the potential dangers of artificial molecular assemblers has led some to envision apocalyptic scenarios. Drexler of the Foresight Institute and others state that artificially created molecular assemblers could represent a competitive threat to all natural life. One scenario suggested danger to life could arise in the form of grey goo which consumes carbon to make more of itself. If unchecked such mechanical replication could potentially consume whole ecoregions or the whole Earth (ecophagy), or it could simply outcompete other natural lifeforms for necessary resources such as carbon, ATP, or UV light (which some nanomotor examples run on). It is worth noting that the 'grey goo' scenario like synthetic molecular assemblers are only based upon speculation.

Possible production strategies

One method to building molecular assemblers is to mimic evolutionary processes employed by biological systems. Biological evolution proceeds by random variation combined with culling of the less-succesful variants and reproduction of the more-succesful variants. Production of complex molecular assemblers might be evolved from simpler systems since "A complex system that works is invariably found to have evolved from a simple system that worked. . . . A complex system designed from scratch never works and can not be patched up to make it work. You have to start over, beginning with a system that works."

However, most published safety guidelines include "recommendations against developing ... replicator designs which permit surviving mutation or undergoing evolution".

safety guidelines

Most assembler designs keep the "source code" external to the physical assembler. At each step of a manufacturing process, that step is read from an ordinary computer file and "broadcast" to all the assemblers. If any assembler gets out of range of that computer, or when the link between that computer and the assemblers is broken, or when that computer is unplugged, the assemblers stop replicating. Such a "broadcast architecture" is one of the safety features recommended by the "Foresight Guidelines on Molecular Nanotechnology" .

See also

In fiction

Molecular assemblers are a popular topic in science fiction. See e.g. the matter compiler in The Diamond Age. The replicator in Star Trek might also be considered a molecular assembler. A molecular assembler is also a key element of the plot of the computer game Deus Ex (called a "universal constructor" in the game).

References

  1. ^ http://pubs.acs.org/cen/coverstory/8148/8148counterpoint.html
  2. http://www.greenpeace.org.uk/MultimediaFiles/Live/FullReport/5886.pdf
  3. Gall, John, (1986) Systemantics: How Systems Really Work and How They Fail, 2nd ed. Ann Arbor, MI : The General Systemantics Press.

External links

Categories: