Prizes are proving themselves as powerful tools to accelerate goal-specific innovation. Diamandis, the founder and chairman of the X Prize Foundation, has built on the success of the $10 million Ansari X Prize that inaugurated private-sector spaceflight in 2004 with Burt Rutan's SpaceShipOne. Currently in play are new prizes for a $10,000 human genome, for a private Moon landing, and for a super-efficient car, with more in the pipeline.

But prize contests so far have focussed on near-term goals---spectacular achievements that can be accomplished in a decade or two. What might be prize-worthy hundred-year goals, or thousand-year goals? What goals might a century of focussed effort transform from the clearly impossible to the merely difficult?