Molecular assembler

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A molecular assembler has been defined as a machine of atomically precise construction capable of assembling molecular moieties according to specific instructions to construct a desired product. 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.

Production through self replication

The nanoscale size of a "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 "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.

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.[1]

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.[2] 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”[3] 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.

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).

External links

Nano-Hive: Nanospace Simulator free software for modeling nanotech entities
Foresight Institute proposes guidelines for responsible development of molecular manufacturing technologies
Center for Responsible Nanotechnology
Molecular Assembler website
Rage Against the (Green) Machine article originally in Wired
Biosafety discussion on assembler risk
Government launches nano study UK EducationGuardian, 11 June 2003
Disinfopedia: dangerous technology
Disinfopedia: pro-technology propaganda
"Unraveling the Big Debate over Small Machines"
Paper on assembly
http://www.zyvex.com/nanotech/nano4/merklePaper.html
Kinematic Self-Replicating Machines (http://www.MolecularAssembler.com/KSRM.htm) online technical book: first comprehensive survey of molecular assemblers (2004) by Robert Freitas and Ralph Merkle

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