Pale Blue Dot - Carl Sagan [39]
It is conventional wisdom now that anything built by the government will be a disaster. But the two Voyager spacecraft were built by the government (in partnership with that other bugaboo, academia). They came in at cost, on time, and vastly exceeded their design specifications—as well as the fondest dreams of their makers. Seeking not to control, threaten, wound, or destroy, these elegant machines represent the exploratory part of our nature set free to roam the Solar System and beyond. This kind of technology, the treasures it uncovers freely available to all humans everywhere, has been, over the last few decades, one of the few activities of the United States admired as much by those who abhor many of its policies as by those who agree with it on every issue. Voyager cost each American less than a penny a year from launch to Neptune encounter. Missions to the planets are one of those things—and I mean this not just for the United States, but for the human species—that we do best.
*Since women astronauts and cosmonauts of several nations have flown in space, “manned” is just flat-out incorrect. I’ve attempted to find an alternative to this widely used term, coined in a more unself-consciously sexist age. I tried “crewed” for a while, but in spoken language it lends itself to misunderstanding. “Piloted” doesn’t work, because even commercial airplanes have robot pilots. “Manned and womanned” is just, but unwieldy. Perhaps the best compromise is “human,” which permits us to distinguish crisply between human and robotic missions. But every now and then, I find “human” not quite working, and to my dismay “manned” slips back in.
CHAPTER 7
AMONG THE MOONS OF SATURN
Seat thyself sultanically among the moons of Saturn.
—HERMAN MELVILLE, MOBY DICK, CHAPTER 107 (1851)
There is a world, midway in size between the Moon and Mars, where the upper air is rippling with electricity—streaming in from the archetypical ringed planet next door, where the perpetual brown overcast is tinged with an odd burnt orange, and where the very stuff of life falls out of the skies onto the unknown surface below. It is so far away that light takes more than an hour to get there from the Sun. Spacecraft take years. Much about it is still a mystery—including whether it holds great oceans. We know just enough, though, to recognize that within reach may be a place where certain processes are today working themselves out that aeons ago on Earth led to the origin of life.
On our own world a long-standing—and in some respects quite promising—experiment has been under way on the evolution of matter. The oldest known fossils are about 3.6 billion years old. Of course, the origin of life had to have happened well before that. But 4.2 or 4.3 billion years ago the Earth was being so ravaged by the final stages of its formation that life could not yet have come into being: Massive collisions were melting the surface, turning the oceans into steam and driving any atmosphere that had accumulated since the last impact off into space. So around 4 billion years ago, there was a fairly narrow window—perhaps only a hundred million years wide—in which our most distant ancestors came to be. Once conditions permitted, life arose fast. Somehow.
The first living things very likely were inept, far less capable than the most humble microbe alive today—perhaps just barely able to make crude copies of themselves. But natural selection, the key process first coherently described by Charles Darwin, is an instrument of such enormous power that from the most modest beginnings there can emerge all the richness and beauty of the biological world.
Those first living things were made of pieces, parts, building