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PH V SICS Of THE IMPOSSIBLE
nology.) If one is given a PC and a tableful of spare electronic parts, it
would be quite difficult to build a machine that would have the capability of making a copy of itself. So if a self-replicating machine is difficult to build on a tabletop, building one on the atomic scale would be
even more difficult.
Second, it's not clear how one would program such an army of
nanobots from the outside. Some have suggested sending in radio signals to activate each nanobot. Perhaps laser beams containing instructions could be fired at the nanobots. But this would mean a separate set
of instructions for each nanobot, of which there could be trillions.
Third, it's not clear how the nanobot would be able to cut, rearrange, and paste atoms into the proper order. Remember that it has
taken nature three and a half billion years to solve this problem, and
solving it in a few decades would be quite difficult.
One physicist who takes the idea of a replicator or "personal fabricator" seriously is Neil Gershenfeld of MIT. He even teaches a class at
MIT called "How to Make (Almost) Anything," one of the most popular classes at the university. Gershenfeld directs the MIT Center for
Bits and Atoms and has given serious thought to the physics behind a
personal fabricator, which he considers to be the "next big thing." He
has even written a book, FAB: The Coming Revolution on Your Desktop-From Personal Computers to Personal Fabrication, detailing his
thoughts on personal fabrication. The goal, he believes, is to "make
one machine that can make any machine." To spread his ideas he has
already set up a network of laboratories around the world, mainly in
third world countries where personal fabrication would have the maximum impact.
Initially, he envisions an all-purpose fabricator, small enough to
place on your desk, which would use the latest developments in lasers
and microminiaturization with the ability to cut, weld, and shape any
object that can be visualized on a PC. The poor in a third world country, for example, could ask for certain tools and machines they need on
their farms. This information would be fed into a PC, which would access a vast library of blueprints and technical information from the Internet. Computer software would then match existing blueprints with
PH V SICS Of THE IMPOSSIBLE
nology.) If one is given a PC and a tableful of spare electronic parts, it
would be quite difficult to build a machine that would have the capability of making a copy of itself. So if a self-replicating machine is difficult to build on a tabletop, building one on the atomic scale would be
even more difficult.
Second, it's not clear how one would program such an army of
nanobots from the outside. Some have suggested sending in radio signals to activate each nanobot. Perhaps laser beams containing instructions could be fired at the nanobots. But this would mean a separate set
of instructions for each nanobot, of which there could be trillions.
Third, it's not clear how the nanobot would be able to cut, rearrange, and paste atoms into the proper order. Remember that it has
taken nature three and a half billion years to solve this problem, and
solving it in a few decades would be quite difficult.
One physicist who takes the idea of a replicator or "personal fabricator" seriously is Neil Gershenfeld of MIT. He even teaches a class at
MIT called "How to Make (Almost) Anything," one of the most popular classes at the university. Gershenfeld directs the MIT Center for
Bits and Atoms and has given serious thought to the physics behind a
personal fabricator, which he considers to be the "next big thing." He
has even written a book, FAB: The Coming Revolution on Your Desktop-From Personal Computers to Personal Fabrication, detailing his
thoughts on personal fabrication. The goal, he believes, is to "make
one machine that can make any machine." To spread his ideas he has
already set up a network of laboratories around the world, mainly in
third world countries where personal fabrication would have the maximum impact.
Initially, he envisions an all-purpose fabricator, small enough to
place on your desk, which would use the latest developments in lasers
and microminiaturization with the ability to cut, weld, and shape any
object that can be visualized on a PC. The poor in a third world country, for example, could ask for certain tools and machines they need on
their farms. This information would be fed into a PC, which would access a vast library of blueprints and technical information from the Internet. Computer software would then match existing blueprints with