NANOTECHNOLOGY—TECHNOLOGY ON A MOLECULAR SCALE - Chemistry: Notable Research and Discoveries - page 49

person's life. In the worst case for nanotechnology, uncontrollable ma-
chines might proliferate and consume all resources, making a kind of
“gray goo” that covers the world.
The current state of nanotechnology is not nearly advanced enough
to pose such extreme threats. Yet it is prudent to plan ahead. The prog-
ress of nanotechnology since Richard Feynman delivered his lecture has
been rapid and may quickly attain a point at which tremendous ben-
efits—and risks—are realized. Organizations such as the Center for Re-
sponsible Nanotechnology, a nonprofit research and advocacy group,
are investing time and thought into approaches that are balanced in
terms of risk and reward. The “gray-goo” scenario is unlikely because
any self-replicating machine would be sensitive to its environment—as
are living organisms—which would make it impossible for the machine
to expand beyond certain boundaries. But the potential threat of any
new technology should be considered along with its benefits.
BuIldIngWITHAToMS
Zettl's oscillator exerts control over the motion of a relatively small
number of atoms, but the goal of some nanotechnology researchers is to
manipulate atoms themselves. Thanks to the development of the Scan-
ning Tunneling Microscope (STM) in 1981, this once unthinkable feat
is not only possible, it has been performed.
As described in the sidebar on pages 50-52, the principles of quan-
tum mechanics are involved in the STM's operation. Considering the
scale of operation, this is unavoidable. Although quantum mechanics
consists of some unfamiliar concepts, the equations provide an accurate
and reliable way of understanding behavior on the atomic level.
Although STMs do a splendid job of providing atomic-scale imag-
es, nanotechnology specialists are also interested in the machine's abil-
ity to move a single atom, as mentioned in the sidebar on pages 50-52.
In 1989, the IBM scientist Don Eigler discovered that he could move
around atoms with the STM. He spelled the company letters, IBM, with
xenon atoms on a nickel surface. Since then, scientists have yielded to a
creative impulse and made a variety of artistic pictures with small num-
bers of atoms. (Such art not only requires an STM to make, it also re-
quires one in order for people to see and appreciate.)
Besides creating interesting pictures, one of the projects that inter-
ests IBM is the use of STM to make even smaller electronic circuits.