Pale Blue Dot - Carl Sagan [102]
which are now left mainly to unfounded fantasy, could be more soberly treated without ceasing to be interesting and could show to even the most adventurous of the young that a world without war need not be a world without adventurous and hazardous glory.* To this kind of contest there is no limit. Each victory is only a prelude to another, and no boundaries can be set to rational hope.
In the long run, these—more than any of the “practical” justifications considered earlier—may be the reasons we will go to Mars and other worlds. In the meantime, the most important step we can take toward Mars is to make significant progress on Earth. Even modest improvements in the social, economic, and political problems that our global civilization now faces could release enormous resources, both material and human, for other goals.
There’s plenty of housework to be done here on Earth, and our commitment to it must be steadfast. But we’re the kind of species that needs a frontier—for fundamental biological reasons. Every time humanity stretches itself and turns a new corner, it receives a jolt of productive vitality that can carry it for centuries.
There’s a new world next door. And we know how to get there.
*Even then it wasn’t easy. The Portuguese chronicler Gomes Eanes de Zurara reported this assessment by Prince Henry the Navigator: “It seemed to the Lord Infante that if he or some other lord did not endeavor to gain that knowledge, no mariners nor merchants would ever dare to attempt it, for it is clear that none of them ever trouble themselves to sail to a place where there is not a sure and certain hope of profit.”
*Russell’s phrase is noteworthy: “adventurous and hazardous glory.” Even if we could make human spaceflight risk-free—and of course we cannot—it might be counterproductive. The hazard is an inseparable component of the glory.
CHAPTER 17
ROUTINE INTERPLANETARY VIOLENCE
It is a law of nature that Earth and all other bodies should remain in their proper places and be moved from them only by violence.
—ARISTOTLE (384–322 B.C.), PHYSICS
There was something funny about Saturn. When, in 1610, Galileo used the world’s first astronomical telescope to view the planet—then the most distant world known—he found two appendages, one on either side. He likened them to “handles.” Other astronomers called them “ears.” The Cosmos holds many wonders, but a planet with jug ears is dismaying. Galileo went to his grave with this bizarre matter unresolved.
As the years passed, observers found the ears … well, waxing and waning. Eventually, it became clear that what Galileo had discovered was an extremely thin ring that surrounds Saturn at its equator but touches it nowhere. In some years, because of the changing orbital positions of Earth and Saturn, the ring had been seen edge-on and, because of its thinness, it seemed to disappear. In other years, it had been viewed more face-on, and the “ears” grew bigger. But what does it mean that there’s a ring around Saturn? A thin, flat, solid plate with a hole cut out for the planet to fit into? Where does that come from?
This line of inquiry will shortly take us to world-shattering collisions, to two quite different perils for our species, and to a reason—beyond those already described—that we must, for our very survival, be out there among the planets.
We now know that the rings (emphatically plural) of Saturn are a vast horde of tiny ice worlds, each on its separate orbit, each bound to Saturn by the giant planet’s gravity. In size, these worldlets range from particles of fine dust to houses. None is big enough to photograph even from close flybys. Spaced out in an exquisite set of fine concentric circles, something like the grooves on a phonograph record (which in reality make, of course, a spiral), the rings were first revealed in their true majesty by the two Voyager spacecraft in their 1980/81 flybys. In our century, the Art Deco rings of Saturn have become an icon of the future.
At a scientific meeting in the late 1960s, I was asked to summarize