ABSTRACT
Today, ‘Spaceship Earth’ has become a compelling and familiar metaphor, conjuring a picture of all the people on earth hurtling through space, dependent for life support on each other and the planet’s limited resources. But there is another equally compelling metaphor needed to make the story complete. It is the image of ‘Time Machine Earth’: the inexorable movement through time from out of the past into the future. Thus, not only are all people on earth space travelers, they are also time travelers. Their tickets through time, however, are good only for a one-way trip. They can travel only forward toward the future.
