The “Pale Blue Dot” was part of a Family Portrait series of images exploring the Solar System.

But we owe the actual recognition of Earth in the legendary photograph to Candice Hansen-Koharcheck, one of the two University of Arizona scientists who developed the command sequence that controlled the timing for each photograph’s exposure. That day, she was sitting in front of a computer at NASA’s Jet Propulsion Lab with her shades drawn when she noticed the tiny speck on an image sent back by the camera she had helped design, which was now 4 billion miles away. She told NPR a few years ago:

It was just a little dot, about two pixels big, three pixels big, so not very large. … You know, I still get chills down my back because here was our planet, bathed in this ray of light, and it just looked incredibly special.

And yet photograph almost never happened — the NASA imaging team feared that aiming the camera at the Sun would damage it. But Sagan himself lobbied long and hard for an attempt. Vice Adm. Richard Truly, former head of NASA, recalls:

I did get a visit from Carl Sagan. We talked about a lot of things. And somewhere in that conversation he mentioned this idea. I thought, heck, with Voyager so far away, if it could turn around and take a picture of the different planets including the Earth, that that would really be cool. And so I was a great advocate of it, although I can’t take any credit for it.

(Those were the golden days when NASA made historic decisions simply because something seemed “cool.”)

Fortunately, it did happen. And four years later, Carl Sagan wrote of the iconic image in the preface to his book titled after it, Pale Blue Dot: A Vision of the Human Future in Space (public library):

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.

But Sagan’s beautiful and timeless words might not be entirely his own — perhaps a manifestation of neurologist Oliver Sacks’s insights on memory and (inadvertent) plagiarism. As historian Robert Poole notes in Earthrise: How Man First Saw the Earth (public library), after the equally iconic Apollo 8 “Earthrise” photograph made its debut in 1968, the poet Archibald MacLeish penned an essay ‘Riders on the Earth,’ in which he articulated a strikingly similar sentiment:

For the first time in all of time, men have seen the Earth. Seen it not as continents or oceans from the little distance of a hundred miles or two or three, but seen it from the depths of space; seen it whole and round and beautiful and small… To see the Earth as it truly is, small and blue and beautiful in that eternal silence where it floats, is to see ourselves as riders on the Earth together, brothers on that bright loveliness in the eternal cold—brothers who know that they are truly brothers.

The essay appeared in The New York Times on Christmas Day that year.

Then again, the similarity in language might simply be an inevitable expression of the overview effect. Whatever the case, the “Pale Blue Dot” endures as a sublimely beautiful cosmic Valentine that reminds us, more than two decades later, of the ineffable relativity of our human scale.

Celebrate the “Pale Blue Dot” and its legacy with some stunning animated adaptations of Sagan’s words.