Pale Blue Dot - Carl Sagan [133]
Another generation later, building on the work of Tsiolkovsky and Goddard, extending von Braun’s technological genius, we were up there in space, silently circumnavigating the Earth, treading the ancient and desolate lunar surface. Our machines—increasingly competent and autonomous—were spreading through the Solar System, discovering new worlds, examining them closely, searching for life, comparing them with Earth.
This is one reason that in the long astronomical perspective there is something truly epochal about “now”—which we can define as the few centuries centered on the year you’re reading this book. And there’s a second reason: This is the first moment in the history of our planet when any species, by its own voluntary actions, has become a danger to itself—as well as to vast numbers of others. Let me recount the ways:
We’ve been burning fossil fuels for hundreds of thousands of years. By the 1960s, there were so many of us burning wood, coal, oil, and natural gas on so large a scale, that scientists began to worry about the increasing greenhouse effect; the dangers of global warming began slowly slipping into public consciousness.
CFCs were invented in the 1920s and 1930s; in 1974 they were discovered to attack the protective ozone layer. Fifteen years later a worldwide ban on their production was going into effect.
Nuclear weapons were invented in 1945. It took until 1983 before the global consequences of thermonuclear war were understood. By 1992, large numbers of warheads were being dismantled.
The first asteroid was discovered in 1801. More or less serious proposals to move them around were floated beginning in the 1980s. Recognition of the potential dangers of asteroid deflection technology followed shortly after.
Biological warfare has been with us for centuries, but its deadly mating with molecular biology has occurred only lately.
We humans have already precipitated extinctions of species on a scale unprecedented since the end of the Cretaceous Period. But only in the last decade has the magnitude of these extinctions become clear, and the possibility raised that in our ignorance of the interrelations of life on Earth we may be endangering our own future.
Look at the dates on this list and consider the range of new technologies currently under development. Is it not likely that other dangers of our own making are yet to be discovered, some perhaps even more serious?
In the littered field of discredited self-congratulatory chauvinisms, there is only one that seems to hold up, one sense in which we are special: Due to our own actions or inactions, and the misuse of our technology, we live at an extraordinary moment, for the Earth at least—the first time that a species has become able to wipe itself out. But this is also, we may note, the first time that a species has become able to journey to the planets and the stars. The two times, brought about by the same technology, coincide—a few centuries in the history of a 4.5-billion-year-old planet. If you were somehow dropped down on the Earth randomly at any moment in the past (or future), the chance of arriving at this critical moment would be less than 1 in 10 million. Our leverage on the future is high just now.
It might be a familiar progression, transpiring on many worlds—a planet, newly formed, placidly revolves around its star; life slowly forms; a kaleidoscopic procession of creatures evolves; intelligence emerges which, at least up to a point, confers enormous survival value; and then technology is invented. It dawns on them that there are such things as laws of Nature, that these laws can be revealed by experiment, and that knowledge of these laws can be made both to save and to take lives, both on unprecedented scales. Science, they recognize, grants immense powers. In a flash, they create world-altering contrivances. Some planetary civilizations see their way through, place limits on what may