The Voyager 1 spacecraft was launched by NASA on September 5, 1977 aboard a Titan IIIE rocket. The space probe was designed to study the outer solar system, flying by Jupiter, Saturn, and then flying through the heliosphere, and eventually into interstellar space. At a speed of about 38,027 mph, the intrepid Voyager 1 covers a distance of about 325 million miles per year. And remarkably — 37 years later — the spacecraft is still sending data to NASA (messages from more than 12 trillion miles away take about 17 hours to reach Earth). Back in 1990, astronomer Carl Sagan, who was a member of the Voyager’s imaging team, persuaded NASA to send commands to turn the spacecraft’s camera around to take one last photo of the Earth (at a distance of about 3.7 billion miles away). The final image shows the Earth as a mere speck (less than 1 pixel) suspended in a brownish band of light, surrounded by the blackness of space. The spectacular photo inspired Sagan to reflect on the significance of life on this tiny planet, a pale blue dot, dwarfed by the mind-boggling vastness of the cosmos:
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.
The Earth is a very small stage in a vast cosmic arena. Think of the rivers of blood spilled by all those generals and emperors so that in glory and triumph they could become the momentary masters of a fraction of a dot. Think of the endless cruelties visited by the inhabitants of one corner of this pixel on the scarcely distinguishable inhabitants of some other corner. How frequent their misunderstandings, how eager they are to kill one another, how fervent their hatreds. Our posturings, our imagined self-importance, the delusion that we have some privileged position in the universe, are challenged by this point of pale light. Our planet is a lonely speck in the great enveloping cosmic dark. In our obscurity – in all this vastness – there is no hint that help will come from elsewhere to save us from ourselves.
The Earth is the only world known, so far, to harbor life. There is nowhere else, at least in the near future, to which our species could migrate. Visit, yes. Settle, not yet. Like it or not, for the moment, the Earth is where we make our stand. It has been said that astronomy is a humbling and character-building experience. There is perhaps no better demonstration of the folly of human conceits than this distant image of our tiny world. To me, it underscores our responsibility to deal more kindly with one another and to preserve and cherish the pale blue dot, the only home we’ve ever known.
For further reading: Pale Blue Dot: A Vision of the Human Future in Space by Carl Sagan, Ballantine Books (1997)
Cosmos by Carl Sagan, Ann Druyan, and Neil deGrasse Tyson, Ballantine Books (2013)
Universe by Robert Dinwiddle, Philip Eales, David Hughes, and Iain Nicolson, DK (2012)