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Like any science book of years gone by, the obvious drawback to Cosmos is that it’s outdated.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.

Pale Blue Dot: A Vision of the Human Future in Space by Carl Sagan

Big thoughts inspired by unmanned space exploration

When astronomer and science educator Carl Sagan (1934-1996) was at the height of his fame and influence in the 1980s and early ’90s, I was a little too young to appreciate what he had to say. Later in life, however, I have come to enjoy his books and consider him a sort of intellectual hero. Sagan’s Pale Blue Dot, a book on planetary science for a popular audience, was published in 1994. Like many of Sagan’s books, this is a collection of essays and articles, some of which were previously published in magazines and journals, that have been adapted to form a cohesive whole. In this case, the common theme tying the chapters together is our solar system and all the worlds therein: the planets, moons, asteroids, comets, and everything in between. Sagan reviews what we’ve already learned (up until 1994) from unmanned spacecraft launched by NASA and the space agencies of other Earth nations. From there, he ventures into informed speculation on future spaceflight missions, manned and unmanned, and the possibility of colonizing other celestial bodies within our solar system.

The pale blue dot referenced in the title is, of course, our Earth. Pale Blue Dot is also the title of a famous photograph taken by the Voyager 1 spacecraft in 1990. In the photo, shot from beyond the orbit of Neptune, the Earth is an infinitesimal dust mote in a sea of black. Sagan specifically discusses the photo in this book of the same title (but the Ballantine ebook edition has no photos, so I had to look it up online). The image is a potent illustration of our insignificance in the universe. In the first few chapters of the book, Sagan dwells on mankind’s tendency towards anthropocentrism, and how each successive astronomical discovery over the past several centuries has proven time and time again that humans from Earth are not the center of the universe. Our insignificance is nothing to be ashamed of, just a matter of fact, and Sagan argues that we can find humble satisfaction in knowing our place as part of the greater whole. 

Not surprisingly, Sagan spends much of the book advocating for a bigger space program and more space missions to learn more about the wonders of our solar system. He argues that although a space program is expensive, NASA’s budget is but a tiny fraction of what the United States spends on weaponry and defense. Much of the was written shortly after Voyager 2’s flybys of Jupiter, Saturn, Uranus, and Neptune. Sagan also discusses at length the findings of some of the earlier Mars and Venus probes. Thirty years after publication, some of the science here maybe outdated, but the philosophical discussions Sagan draws from the science are still valid, and the issues that he raises concerning the space program are still relevant today. Sagan is a big advocate for unmanned space missions. He also debates the pros and cons of manned spaceflight, first asking if it’s really worth the cost in money and lives, then building an argument for a mission to Mars. Other more futuristic projects that Sagan contemplates are developing technology to deliberately redirect asteroids and comets, terraforming other planets and moons for human colonization, and a beefing up of the SETI program’s monitoring of radio waves from space.

Sagan points out that if mankind wants to perpetuate its species forever, we are going to have to eventually spread out and colonize other astronomical bodies before we destroy the Earth or our dying Sun does it for us. Can’t argue with that logic. Sagan, however, might strike some as extreme in his urging that we start working towards such an extraterrestrial diaspora right now. I for one find his “Why wait?” attitude inspiring. Even if we never succeed in building a hotel on Mars, imagine all we would learn in the attempt. Throughout his career, Sagan was driven by the excitement of unlocking the secrets of the universe and building upon humanity’s shared storehouse of knowledge. When you read Pale Blue Dot, that excitement is infectious.

The Demon-Haunted World: Science as a Candle in the Dark by Carl Sagan

Championing skepticism over superstition

The Demon-Haunted World, published in 1996, is a collection of essays by astrophysicist turned popular science communicator Carl Sagan (1934–1996). Many of these essays were originally published as articles in various magazines and then adapted for this book. In particular, Sagan mentions Parade magazine, a nationwide Sunday newspaper supplement, as one recurring venue for his writings. Four of the book’s 25 chapters were cowritten by Sagan’s wife and frequent collaborator Ann Druyan.

In this book, Sagan tackles many different categories of the paranormal or pseudoscience, including angels and demons, reincarnation, ghosts, spiritualism, communication with the dead, hypnotism, UFOs, witchcraft, and more. Sagan begins by assessing the state of each belief in today’s society, and then talks about ways of addressing such topics. By explaining the scientific method and the logic techniques of “baloney detection,” Sagan instructs readers in how to practice intelligent skepticism. Probably because of his astronomical interests, the most thoroughly covered topic in this volume is that of UFOs and alien abductions. Sagan looks for scientific reasons behind why so many people claim to have been abducted and sexually abused by extraterrestrials, which leads him into the psychology of hallucinations and false memories. In addition to such supernatural myth-busing, Sagan also laments the sorry state of science education in America and offers suggestions on how we can improve scientific literacy. He is also critical of the scarcity of sound science presented in the news media, political rhetoric, and popular entertainment.

There are few figures of my lifetime that I admire more than Sagan. As far as I can recall, I agree with everything he has to say about matters pertaining to science and religion. He was a veritable knight in elbow-patched blazer the way he fearlessly championed rationalism and science to an overly religious and superstitious American public. The fact that I agree with his views so unilaterally, however, makes the reading of his writings less than exciting for me. I find this common when reading other writers of an atheist or freethinking bent. They’re basically just telling me things I’ve already figured out for myself. Sagan doesn’t have to convince me, because I was already convinced before I picked up the book. 

For similarly minded readers, the best this book has to offer is its revelations on just how pervasively pseudoscience and superstition have permeated our society. Since the book was published in 1996, I would assume the statistics Sagan cites regarding the number of Americans who believe in biblical literalism, ghosts, psychics, alien abductions, and so on are outdated, but I’m afraid those statistics have probably only gotten worse since then. The internet (which existed in 1996 but didn’t dominate our lives to the extent it does now) has only amplified conspiracy theories and tall tales of the paranormal, and it seems like American politicians become more religious and less scientific with each election. If you are a rationalist, and you weren’t already ashamed of American anti-intellectualism, you’ll likely be mortified after reading The Demon-Haunted World.

Fortunately, this book is so well-written that Sagan may very well have changed many minds that were on the fence about astrology, witchcraft, UFO abductions, and the like. His tone throughout the book is that of a hopeful educator. He wants to change people’s minds, but he doesn’t stoop to insulting people’s beliefs. He does, however, go after some prominent paranormal hucksters. Though I felt like much of the book’s content was familiar and just plain common sense, I’m glad somebody wrote this book. The world (or at least the United States) really needs it, and no one could have written it better than Sagan.

Broca’s Brain: Reflections on the Romance of Science by Carl Sagan

Interdisciplinary grab bag
Broca’s Brain, a book by astronomer and science writer Carl Sagan, was published in 1979. The title refers to the 19th century French neuroscientist Paul Broca, who is discussed in the first chapter. The subtitle, Reflections on the Romance of Science, is not entirely successful as a blanket statement sufficiently generic enough to encompass the contents of what is essentially a grab bag of 25 miscellaneous articles, essays, and lectures that have been repurposed into a book. The writings collected in this volume were previously published from 1974 to 1979 and vary widely in subject matter, interest, and degree of difficulty.

The chapters are divided into categories, but even those are loose enough to be almost arbitrary. One chapter is a brief biological sketch of Albert Einstein that focuses as much on his political and humanitarian efforts as his scientific accomplishments. Another chapter is a critical essay on science fiction in which Sagan names some of his favorite novels. The bulk of the book, however, is devoted to Sagan’s bread and butter, planetary science. The contents of this book were written at a time when the Viking spacecraft had recently landed on Mars and Voyager had not yet reached Saturn, so most of Sagan’s speculations on the solar system have since been either confirmed or disproved by subsequent unmanned space exploration. Sagan also devotes much discussion to the possibility of life on other worlds and our ability to find it, and his erudite thoughts on these topics are still very much relevant today. Though Sagan was known for the accessibility of his scientific writings, not every piece in this collection was intended for the general reader. His chapter on the history of 19th century astronomy, for example, is clearly aimed at practitioners in that field, and one would probably need a master’s degree in the subject to fully understand everything the author is saying.

A section of the book entitled Paradoxers includes chapters in which Sagan refutes various forms of faux science. Sagan was one of the world’s foremost advocates for science over superstition and mysticism. While I admire him for taking on that role, those reading a book by Sagan have probably already made up their minds in favor of science. The biggest disappointment with Broca’s Brain is that Sagan spends twenty percent of the entire book disproving the theories of Immanuel Velikovsky, who made all kinds of ridiculous and unsubstantiated claims about the history of the solar system. There is also a chapter about a man who declared himself the second coming of Christ. Someone had to step up and answer these false prophets, and I am glad Sagan took up the challenge, but I didn’t feel these chapters were a productive use of my reading time. Rest assured, however, that elsewhere in the book Sagan more thoughtfully and philosophically addresses the contentious relationship between science and religion, proving himself one of rationalism’s most outspoken and eloquent proponents.

After reading Broca’s Brain, I would not hesitate to call Sagan a genius. The man can write intelligently and articulately about any subject he puts his mind to, within or without the realm of science. Even so, I can’t say I enjoyed every one of the 25 essays included here, for the reasons discussed above. Still, I’m glad I read the book, and overall this collection of Sagan’s writings on the wonders of the universe left me with a profound feeling of secular inspiration. If that’s what he means by the “romance of science,” then so be it.
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