Which gets us back to outer space. In our neighborhood alone, there are thousands of asteroids with enormous riches -- in gold, platinum, rare earth metals, etc. Planetary Resources Inc., an asteroid mining firm started last year by director James Cameron (ironic given the politics of his film "Avatar") and some Microsoft and Google billionaires, has its sights on several rocks worth anywhere from hundreds of billions to tens of trillions of dollars. And these are just the chunks scattered around our orbital backyard and near enough to exploit with existing technology. There are also plenty of balls of ice out there that might be convertible into fuel for further space exploration.