Cosmos by Carl Sagan

Big universe, big thoughts

The 1980 PBS TV series Cosmos was a landmark in the history of television. The companion book to that series, also published in 1980, was the bestselling science book of all time (until Stephen Hawking beat it a few years later). The Cosmos book has 13 chapters that parallel the 13 episodes of the TV program. Alexander von Humboldt published the original Cosmos book back in 1845 to 1862, and Sagan does mention Humboldt in a footnote. The intent by both authors was to summarize and encapsulate in one volume the state of scientific knowledge on the heavens and the earth. Though Humboldt’s Cosmos was popular in its day, his was a pretty dry scientific text compared to Sagan’s more accessible and inspirational book. The way Sagan combines science writing with philosophy, skepticism, and freethought reminds me of another book from the end of the 19th century: Ernst Haeckel’s The Riddle of the Universe.

As one would expect from an astronomer and planetary scientist, Sagan spends much of Cosmos discussing the planets and other bodies in our solar system, as well as galaxies, the universe as a whole, space travel, the Big Bang, and the search for extraterrestrial life. In addition, however, he discusses particle physics, the origin of life, DNA, evolution, the history of science and astronomy (particularly in ancient Greece), and the human brain. The final chapter of Cosmos is about nuclear war. Although still a threat, Armageddon is not on people’s minds as much as it was in the ‘80s, and disarmament now seems further from reality.

Like any science book of years gone by, the obvious drawback to Cosmos is that it’s outdated. Sagan doesn’t really say anything wrong in this book, but what’s omitted is notable. There’s no mention of quantum physics or dark matter, for example. Sagan wrote Cosmos after Voyager 2 had performed its flyby of Jupiter but before it had reached Saturn. There was no Hubble Space Telescope. The existence of exoplanets was still suspected, not confirmed. The nearly fifty intervening years since publication, however, didn’t really bother me. I consider myself pretty well-versed in astronomical matters for a general reader, but I still learned many interesting scientific facts from Sagan’s Cosmos. Sagan is great at putting things into perspective, both humanity’s insignificance in the universe and the immensity of space and time. (He’s much more eloquent than the “billions and billions” catch phrase for which he’s known.)

I’d read much of this information before, but never as succinctly nor as elegantly put as Sagan presents things here. The other famous science book of this era was, of course, Stephen Hawking’s A Brief History of Time. Though also aimed at the general reader, Hawking’s book is not easy to understand and his explanations aren’t quite user-friendly for the layman. Sagan, on the other hand, is great at explaining complex scientific phenomena in simple terms that anyone with a high school education can understand, without dumbing down the scientific content or the philosophical implications of the matters discussed.

Sagan stopped short of declaring himself an atheist, but for readers of a freethinking persuasion, he is one of the best areligious writers out there, if not the best. He is a superb rationalist preacher, without the pretensions or cynicism of Richard Dawkins and other “neo-atheists.” Since Sagan’s death, others have tried to assume his role as leading spokesman for science—most recently Neil deGrasse Tyson and Bill Nye—but no one has quite matched his passion, eloquence, and trustworthiness as a public intellectual. Cosmos, although published in the middle of his career, is Sagan’s magnum opus, the distillation of his entire career. His other books may focus in more detail on some of the topics presented here, but no book better encapsulates his thought in its totality as this one. In the 1980s, this book was a must-read, and today it’s still an important and rewarding work for anyone who cares about science.