The Pale Blue Dot

And a Bright Evening Star

On Christmas Eve, 1968, Jim Anders snapped one of the most profound photographs in history. Anders was one of three men aboard Apollo 8, the first manned spacecraft to orbit the Moon, and as they circled the Moon they suddenly noticed an incredible sight—the Earth was rising off the Moon’s horizon. The photograph became known as “Earthrise” and its incredible perspective of our beautiful planet sparked the rise of the environmental movement. It is in Life magazine’s list of “100 Photographs that Changed the World.”

Four years later the last manned mission to the Moon took another famous photograph of Earth, shortly after departing Earth orbit for the Moon. It may be the most widely distributed image in human history and is called “The Blue Marble” because from the perspective of the crew, the Earth was about the size of a marble.

In 1990 Voyager 1, a small NASA spacecraft, had finished its tour of the solar system and took a picture of Earth as it headed for interstellar space. Voyager 1 was the first spacecraft to leave the solar system and today is the farthest man-made object from Earth. For almost ten years leading up to the 1990 photograph, astronomer and science popularizer Carl Sagan had promoted the idea of Voyager 1 taking a picture of Earth as the spacecraft made its way out of the solar system. But concerns about instrument damage from the Sun’s glare delayed the photograph, and shrinking budgets and staff put it at risk altogether. Finally the NASA Administrator intervened to have the photograph taken. The photo is called “The Pale Blue Dot” for at a distance of almost 4 billion miles Earth appears as a tiny blue dot (see blue pixel right of center in the brown band). That name also served as the title of Sagan’s 1994 book about the future of space travel and much more. Sagan was a proponent of what historians call the Copernican Principle—the idea that Earth, and more generally the human race, are not special or privileged, but rather are merely a statistical result of chance evolutionary events—which was an important theme in Sagan’s book. Like the ancient Epicureans, Sagan used the inconceivable vastness of the universe, as implied by The Pale Blue Dot photograph, to advance the Copernican Principle theme (though its sixteenth century namesake astronomer, Nicolaus Copernicus, would not have agreed) and its underlying evolutionary ideas:

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.
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Look again at 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.

And if the reader did not properly infer the religious implications, Sagan made them clear:

Ann Druyan suggests an experiment: Look back again at the pale blue dot of the preceding chapter. Take a good long look at it. Stare at the dot for any length of time and then try to convince yourself that God created the whole Universe for one of the 10 million or so species of life that inhabit that speck of dust. Now take it a step further: Imagine that everything was made just for a single shade of that species, or gender, or ethnic or religious subdivision. If this doesn’t strike you as unlikely, pick another dot. Imagine it to be inhabited by a different form of intelligent life. They, too, cherish the notion of a God who has created everything for their benefit. How seriously do you take their claim?

Clearly photographs can convey, or be used to convey, ideas that go far beyond the photograph itself. That is why it just may be important that this week another profound photograph was taken of Earth.

The NASA rover Curiosity has been exploring the surface of the planet Mars. It has discovered many interesting things, but in the twilight hours after sundown on January 31, the robotic explorer turned a camera upwards to the sky, and toward home. With the Martian hills on the horizon, Curiosity photographed a bright “Evening Star” in the Martian sky called Earth. What will this photograph inspire?