“From this vantage point, our obsession with nationalism is nowhere in evidence. The Apollo pictures of the whole Earth conveyed to multitudes something well known to astronomers: On the scale of worlds—to say nothing of stars or galaxies—humans are inconsequential, a thin film of life on an obscure and solitary lump of rock and metal.”

Sagan describes the response to the first photograph of the whole Earth by the crew of Apollo 11. It is the first image in human history that captures Earth as a single object. As Sagan notes, the photograph also impresses upon the viewer that things humans find important, like national identity, are short-lived human constructs.

“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.”

Sagan here is describing his response to the “pale blue dot” photograph taken by Voyager 1 in 1990. This quote, perhaps the most reprinted of Sagan’s career, captures his belief that journeying into space will provide the perspective we need to recognize that humans should work collectively to make the future a better place. Earth is a limited resource, and human misconceptions and self-serving actions are currently threatening our survival.

“After the Earth dies, some 5 billion years from now, after it is burned to a crisp or even swallowed by the Sun, there will be other worlds and stars and galaxies coming into being—and they will know nothing of a place once called Earth.”

The scale dramatized by the “pale blue dot” photograph and implied by any other image of the cosmos is often thought of as only spatial. The universe is huge and the distance between stars is almost inconceivable. But Earth, only 4.5 billion years old, is also insignificant in the context of time.