Cosmos - Carl Sagan [154]
The information in our genes is very old—most of it more than millions of years old, some of it billions of years old. In contrast, the information in our books is at most thousands of years old, and that in our brains is only decades old. The long-lived information is not the characteristically human information. Because of erosion on the Earth, our monuments and artifacts will not, in the natural course of things, survive to the distant future. But the Voyager record is on its way out of the solar system. The erosion in interstellar space—chiefly cosmic rays and impacting dust grains—is so slow that the information on the record will last a billion years. Genes and brains and books encode information differently and persist through time at different rates. But the persistence of the memory of the human species will be far longer in the impressed metal grooves on the Voyager interstellar record.
The Voyager message is traveling with agonizing slowness. The fastest object ever launched by the human species, it will still take tens of thousands of years to go the distance to the nearest star. Any television program will traverse in hours the distance that Voyager has covered in years. A television transmission that has just finished being aired will, in only a few hours, overtake the Voyager spacecraft in the region of Saturn and beyond and speed outward to the stars. If it is headed that way, the signal will reach Alpha Centauri in a little more than four years. If, some decades or centuries hence, anyone out there in space hears our television broadcasts, I hope they will think well of us, a product of fifteen billion years of cosmic evolution, the local transmogrification of matter into consciousness. Our intelligence has recently provided us with awesome powers. It is not yet clear that we have the wisdom to avoid our own self-destruction. But many of us are trying very hard. We hope that very soon in the perspective of cosmic time we will have unified our planet peacefully into an organization cherishing the life of every living creature on it and will be ready to take that next great step, to become part of a galactic society of communicating civilizations.
*Thus all of the books in the world contain no more information than is broadcast as video in a single large American city in a single year. Not all bits have equal value.
†Some sequoia trees are both larger and more massive than any whale.
*There is a curious counterpoint to this story. The preferred radio channel for interstellar communication with other technical civilizations is near a frequency of 1.42 billion Hertz, marked by a radio spectral line of hydrogen, the most abundant atom in the Universe. We are just beginning to listen here for signals of intelligent origin. But the frequency band is being increasingly encroached upon by civilian and military communications traffic on Earth, and not only by the major powers. We are jamming the interstellar channel. Uncontrolled growth of terrestrial radio technology may prevent us from ready communication with intelligent beings on distant worlds. Their songs may go unanswered because we have not the will to control our radio-frequency pollution and listen.
*The arithmetic based on the number 5 or 10 seems so obvious that the ancient Greek equivalent of “to count” literally means “to five.”
*A recent analysis suggests that 96 percent of all the species in the oceans may have died at this time. With such an enormous extinction rate, the organisms of today can have evolved from only a small and unrepresentative sampling of the organisms that lived in late