It's clear that the future of the human race lies beyond the finite limits of our home planet. Whether it's mining asteroids or exploring distant stars, the potential applications of space travel are infinite. At present, however, we are held back from our conquest of the cosmos by our lack of technological sophistication.

Today, the most inspiring feats of engineering occur at a scale that is invisible to the naked eye. In stark contrast to skyscrapers, space shuttles, and other examples of macroengineering that dramatically shaped the 20th century, the 21st century will be defined by its feats of nanonengineering, which is engineering that occurs at the smallest possible scales.