The Singularity is Near: When Humans Transcend Biology

by Ray Kurzweil

Nanotubes Are Still the Best Bet. In The Age of Spiritual Machines, I cited nanotubes—using molecules organized in three dimensions to store memory bits and to act as logic gates—as the most likely technology to usher in the era of three-dimensional molecular computing. Nanotubes, first synthesized in 1991, are tubes made up of a hexagonal network of carbon atoms that have been rolled up to make a seamless cylinder.7 Nanotubes are very small: single-wall nanotubes are only one nanometer in diameter, so they can achieve high densities. They are also potentially very fast. Peter Burke and his colleagues at the University of California at Irvine recently demonstrated nanotube circuits operating at 2.5 gigahertz (GHz). However, in Nano Letters, a peer-reviewed journal of the American Chemical Society, Burke says the theoretical speed limit for these nanotube transistors “should be terahertz [1 THz = 1,000 GHz], which is about 1,000 times faster than modern computer speeds.”8 One cubic inch of nanotube circuitry, once fully developed, would be up to one hundred million times more powerful than the human brain.9