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.