In his 1986 book Engines of Creation: The Coming Era of Nanotechnology, Eric Drexler, an engineer and futurist, imagined a theoretical scenario in which self-reproducing nanometre-sized machines called replicators – powered by the sun, blown about by the wind, and feeding on naturally occurring chemicals – chewed up every living thing on Earth and left in their wake a “grey goo.”
Drexler’s idea was a theoretical extreme, but the notion took hold among sci-fi writers, and “grey goo” became closely (and, many have argued, unfairly) associated with nanotechnology. Michael Crichton used the idea as the basis for his 2002 novel Prey, in which swarms of tiny, flying, evolving robots “infect” people, causing them to melt. Crichton imagined a world where nano-bots and humans become locked in a species’ struggle to survive.
Recently, however, Drexler consigned the “grey goo” scenario to myth. In an opinion piece published in June in the journal Nanotechnology, he and co-author Chris Phoenix argue that there are too many barriers for runaway replication to occur. They point out that the chemicals that occur in nature are simply too varied (think of the difference between the chemical makeup of a dandelion and a lion) to allow replicators to feed on everything.
They also express concern that scaremongering over the near-impossible “grey goo” scenario has hampered rational public debate about nanotechnology and diverted attention from real safety concerns. “Nanotechnology-based fabrication can be thoroughly non-biological and inherently safe,” according to the opinion piece, which also states that nano-bots can be made without the ability to move about, use natural resources or undergo incremental mutation.