Book Review: Pale Blue Dot

Pale Blue Dot by Carl Sagan
Pale Blue Dot by Carl Sagan

Pale Blue Dot: A Vision of the Human Future in Space by Carl Sagan is the FIRST work by Sagan I’ve ever read. Sagan wrote many books both fiction and non-fiction, and I’ve yet to get to any of them. I suppose the closest I’ve come is seeing the movie Contact (1997), with Jodi Foster playing Eleanor Arroway (a great movie!).
Pale Blue Dot is a non-fiction, however, and is Sagan’s analysis of the role space will play in humanity’s future. It was written in 1994, and therefore one of his last publications, as Sagan tragically died in 1996.
The title of the book, Pale Blue Dot, was taken from the instantly infamous Pale Blue Dot photograph taken by Voyager 1 in 1990. The back story to that image is worth describing before actually talking about the book itself.

After the Voyager 1 space craft had completed its primary mission and sailed past the furthest planet (Pluto at the time), Carl Sagan requested that the Voyager team turn the cameras of the distant space probe back at the centre of the Solar System and take images, thereby taking a ‘family portrait‘ of Earth and its planetary siblings. It was only able to capture Jupiter, Earth, Venus, Saturn, Uranus, and Neptune (Mercury, Mars, and Pluto were too hard to image). As important as the family portrait is, the image of Earth left most breathless. It was with prescience that Sagan pushed for the family portrait. I’m sure he didn’t know exactly what the images would behold, but he knew it would be important. Here is the image, can you see Earth?

[Roll mouse over to animate] The infamous image. Taken by Voyager 1, a space probe launched by a species inhabiting that tiny little mote of dust, suspended in a sunbeam.

Can you see it? Can you see our tiny little Earth? Look harder. There, ‘suspended in a sunbeam,’ is a tiny pale blue dot. This is what Sagan had to say:

From this distant vantage point, the Earth might not seem of any particular interest. But for us, it’s different. Consider again that dot. That’s here. That’s home. That’s us. On it everyone you love, everyone you know, everyone you ever heard of, every human being who ever was, lived out their lives. The aggregate of our joy and suffering, thousands of confident religions, ideologies, and economic doctrines, every hunter and forager, every hero and coward, every creator and destroyer of civilization, every king and peasant, every young couple in love, every mother and father, hopeful child, inventor and explorer, every teacher of morals, every corrupt politician, every “superstar,” every “supreme leader,” every saint and sinner in the history of our species lived there – on a mote of dust suspended in a sunbeam.

It’s hard to imagine the immensity of space and time. Our brains are designed to think in distances that scale roughly with our ability to travel regularly, and in time that scales roughly with our lifespan. In looking at the above image, Sagan hoped you would see the fragility of our planet. Giving you a taste of the feeling that almost all astronauts get after seeing Earth from orbit. A realization of just how important it is for us to work together.
In his book, Pale Blue Dot, Sagan took this a step further, creating a short analysis of the importance of the human exploration of space. Over my years as an astronomer and science communicator, I’ve developed lots of good reasons and justifications for our continued foray into the unknown ocean of space. These reasons ranging from spin-off technology (seriously…a huge upside) to the intrinsic value of exploration and discovery. What struck me about Sagan’s book was that although he talked extensively about these as, in general, good reasons to explore space, they weren’t the BEST reason. Or rather, they weren’t enough. Not ENOUGH? What could possibly be better than the reasons I’ve already thought up and read about? Sagan goes on to argue that the single greatest reason to explore space is the survival of the species.
Although I had heard this argument before (from everyone to my colleagues/friends to Stephen Hawking), I had not given it as much thought as perhaps I should have. It is possible that we could destroy ourselves through nuclear war, yes, but that’s not the survival Sagan is talking about. He’s speaking about asteroids. There is a very non-zero chance that at some point in the future a rock big enough to destroy human life will collide with Earth. Exploring space and developing new technologies is the only way to search out and redirect incoming asteroids. Further, if incoming asteroids cannot be redirected it is of vital importance to the species that we have settled elsewhere.
A great book; it is worth every page. Highly recommend reading.
PostScript: These don’t have really much to do with the notes I made above, but were things I wanted to remember.
1. Lucretius Carus (99 BC to 55 BC). Sagan indicated in the book that Lucretius was one of the first to popularize science. Lucretius wrote a poem called De Rerum Natura (‘On the Nature of Things’), wherein he describes the physics of nature (or at least..that known at the time) through beautiful language and poetic imagery. Though I haven’t read it yet, this piece on the New Yorker looks like it covers Lucretius’ work very well.
2. Quote: ‘Travel is broadening.’ I wrote this quote down while reading the book (I wish I marked the page number). It struck me personally. I love traveling (I have a whole tag dedicated to it), and see traveling as a way to both learn and explore new places, but also reflect upon where I’ve been so far. Half of the learning you do while travelling is done when you return to your place of origin and look at it through eyes with more experience. Travel IS broadening. Well said Sagan.
3. Planetary Conjunction. Sometimes planets align in the sky, but rarely do all 5 naked eye planets meet. In Sagan’s book he indicates a date where this did happen: just before dawn on 4 March 1953 BC. This intrigued me. I wondered what it would look like. Happily, I happen to have access to a planetarium (though I could have used free software) and went and checked it out. After playing around a bit, I realized I had to put in the year 1952 BC. Either that means I wrote it down wrong (probable), Sagan wrote it down wrong (doubtful), or the issue was in how year zero was counted. Meh. Either way….it would be amazing to see all the planets in one little group like that.

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