Cosmos

Sagan argues that the same processes that led to life on Earth should operate on countless stars and planets both younger and older than our solar system.

If alien life forms exist, what might they know? Binary digits or bits can measure the amount of information known, as Sagan explains in detail; beings on other worlds may have 10, 100, or 1,000 times more bits of knowledge (and of different kinds) than any human or combination of humans.

Among the dominant intelligences and grandest inhabitants of the Earth are the great whales. Whales’ lives feature long childhoods, suckling mothers, and a great deal of play. They actually evolved from land mammals, contrasting with the common story of animal evolution going from aquatic to terrestrial. Whales have adapted to murky depths where sight is limited by developing a tremendous sense of sound. Whale song is still not understood, but its length (15 minutes to an hour) and frequent repetitions, the fact that whales can pick up particular songs where they left off, and the fact that groups of whales sing together, are fascinating features. Humans are the primary danger to the whales, who did not have to deal with humans for 99.9% of their existence. Human noise pollution alone, since the invention of the steamship, has systematically limited the whales’ ability to communicate over the same ocean distances they once did.

A single cell contains the full catalogue of how to recreate a full being—DNA. Additionally, the emotions and behavior patterns of a brain are not confined to humans, and many animals have feelings. However, what sets humans apart is the development of the cerebral cortex, which developed when the prior human brain could no longer store all the information necessary to survive.

For the author, civilization best shows its potential for liberation through the modern library. In general, writing is perhaps the greatest of human inventions: “Books break the shackles of time, proof that humans can work magic” (281). The author briefly traces the evolution of writing and printing and concludes that the health of a civilization can be gauged by how well those within it support and sustain their libraries.

The author wonders whether humanity would have developed if conditions were even slightly different. For example, no one knows what wiped out the tremendously powerful and plentiful dinosaurs—the explosion of a nearby star is one hypothesis—but whatever happened, the demise of these enormous animals lessened the pressure on mammals. To imagine how other civilizations might develop, humans should study the intelligent inhabitants of the Earth—whales, apes, humans—but that this is, ultimately, limiting.

The two Voyager spacecraft were equipped with two kinds of equipment: one set for gathering information, and another portraying the humans who made the crafts. Information about our genes, brains, and libraries was sent out to any interstellar being who might be able to intercept and interpret it. Sagan ends the chapter with the hope that if humanity is able to unify the Earth peacefully, its inhabitants “will be ready to take the next great step, to become part of a galactic society of communicating civilizations” (289).

To date, there is no compelling evidence for extraterrestrial visits to Earth. As a prelude to discussing possible communication with extraterrestrials, Sagan traces the history of Jean Francois Champollion, a 19th-century Frenchman who was a key figure in the attempts to interpret Egyptian hieroglyphics. Champollion resisted the idea that the hieroglyphs were simply a “substitution cypher,” with, for example, a lion corresponding to a letter “l”, and an eagle to a letter “a”, and so on (296). By translating hieroglyphics, Champollion opened a one-way communication with another civilization not heard from for centuries.

Radio waves provide one possible means for communication over interstellar distances. The largest semi-steerable radio/radar observatory on Earth is the Arecibo Observatory in Puerto Rico, which has been used to listen for intelligent signals from space and to send one out. It could communicate with an identical radio telescope on a planet as far as 15,000 light years away. Since many and perhaps most stars have planets, there could be as many as a billion planets upon which technologically advanced civilizations could have arisen at least once, which is not to say they would still be in existence. The author fears that the greatest impediment to communicating with other civilizations may be their penchant for destroying themselves once they reach a certain technological phase. This is in addition to the vast reach of the Cosmos: Messages from Earth may simply not have reached other civilizations as of yet.

The author outlines his concerns about the possibilities of nuclear war and the shocking magnitude of such a war if it were to happen. English mathematician L. F. Richardson, who collected data on hundreds of wars fought between 1820 and 1945, found that the more people killed in a war, the less likely a war of that type was to happen. Over time humans have tempered the “reptilian” (326) parts of the brain with greater use of reason, but given the corresponding increase in the power of human weapons, Sagan wonders whether humanity’s reliance on reason has improved enough. Full-scale nuclear war has never happened, but if it does, it will be too late to re-do the statistics.

The author does find some optimism in some recent fundamental societal changes, such as the near-elimination of abject slavery, a move toward equality between men and women, some wars being stopped at least in part due to the revulsion of regular citizens of the aggressor nations, and a new consciousness developing that all humans are of one species. He believes it would be a great thing if the people of the Earth could somehow be integrated without destroying cultural differences. This era could be memorable for avoiding self-destruction and beginning the human journey to the stars.