Like the Romans, who once mistakenly thought that their empire ruled “all the world that mattered,” humans until recently could be content in their belief that they were already teh lords of the only relevant piece of cosmic real estate. We now know that such self-satisfied belief was ignorance. We realize now that the universe “that matters” is far vaster than our one little world. A few years ago it was possible for a scientifically educated person to believe that our galaxy contained only one inhabited planet.
The evidence is now before us that we live in a system containing billions of habitable and inhabited worlds. A few years ago, no one knew that incoming extraterrestrial objects, asteroids, have had a decisive influence on the survival and evolution of life on Earth. Now we know, and in knowing are faced with the fact that humanity’s span on Earth can only be made secure if we gain control of the solar system’s flight traffic. A few years ago, “practical” people with full access to all relevant facts could reasonably assert that the necessary costs involved in space travel were so large as to make the notion of a spacefaring civilization a chimera. But now we know that technologies can be brought into existence that can make this wider universe accessible to us, a universe that, therefore, in all probability, is already being accessed by others.
Under such circumstances, to be content with the Pax Mundana, humanity must not only blind itself, but lobotomize itself as well.
We stand on the threshold of the universe, considering whether we should step forward or step back. The question has been posed to us: Will humanity retreat and allow itself to be, and to see itself as, mere passengers adrift in a sea of stars? Or will we step forward and, in taking hold of our solar system, take charge of our destiny, a species fully capable of contending with the challenges to come? The choice is ours.
Robert Zubrin | Entering Space: Creating A Spacefaring Civilization