Image/Data/Interview – KW


In the Pale Blue Dot photograph a spectrum of light rays shine at a slight angle across the black background. Near the middle of the most defined ray of light is a pale dot. This grainy image is not impressive on its own, but Carl Sagan believed that it was worth endangering the instruments of the Voyager 1 spacecraft to obtain it and he would title a book after it. In the first chapter of that book Sagan reads this image in sweeping and rich language that establishes the responsibilities that people have to each other and to their home planet. The photograph presents a cosmic viewpoint that informs the need for these responsibilities.

Sagan begins his reading with a description of how the image was taken by the Voyager 1 spacecraft from a distance beyond the orbits of the most distant planets. He describes the spacecraft receiving an “urgent” message from Earth and how it “obediently” obeyed the message by turning its cameras back towards the Solar System.i Although Sagan later bemoans the use of language that invests inanimate objects with agency he is very willing to use this language in regards to the semi-autonomous computer intelligence of the Voyager spacecraft. Sagan then relates the technical details of how the image is formed by pixels, something that was not a household technology at the time, and how the signal carrying the data obtained by Voyager traversed light-hours over a period of months to finally emerge as a series of images.ii The implied message is that this image is the product of science, even if it does not exist to fulfill a scientific goal.

There was opposition to the image being obtained because it was not in pursuit of a scientific goal. Although Sagan began to press for the image in 1981, after Voyager 1 had completed its close approach to Saturn, the image was not taken until 1990. Pointing Voyager‘s camera back towards Earth meant pointing in the direction of the Sun and a risk of destroying the instruments. Even after both Voyager spacecraft had completed all potential close encounters the opposition remained. Eventually the NASA administrator intervened in favor of taking the images that would include the Pale Blue Dot. Sagan believed this delay was ultimately beneficial to the end product.iii The image he hoped would show the small and insignificant Earth showed it from an even greater distance. The delay also allowed the image of Earth to be taken as part of a series of photographs attempting to image all the planets as they would appear from the edge of the Solar System.

Sagan initially presents the contents of the Pale Blue Dot in prosaic language. The planets seen from this distance are “like the planets seen with the naked eye from the surface of the Earth- luminous dots, brighter than most of the stars.” This establishes that an observer at this distance can only know very little about the planet Earth. Sagan dismisses the ray of light which encompasses the Earth as an “accident of geometry and optics.”iv The sun is not shining on Earth in any special way. The blue and white coloration of Earth is explained in terms of the interactions of light with air and water, but Sagan points out that we are only aware that air and water are the source of the coloration because we live here, to an outside observer Neptune is also blue despite having a very different composition. Sagan states that the Earth “might not seem of any particular interest” from this perspective.v This outsider perspective is used recurrently by Sagan throughout his works and is normally couched in terms of how an intelligent alien visitor may view our world, our species, and our societies.

Sagan then abandons the outsider perspective and asks the reader to look again at the image saying “That’s here. That’s home. That’s us”. Sagan precedes in an attempt to encapsulate the breadth of human experience, on both the personal and mass scale, in the span of three paragraphs. He establishes that he is speaking about the home of “every human being who ever was” and that the Earth contains the sum of all human experience, every belief, and every culture. It is “the aggregate of our joy and suffering.” A list of pairs, often opposites, follows. Beginning with “every creator and destroyer of civilization” the list establishes a semi-poetic rhythm. It returns to the ray of light that Sagan had previously dismissed as an accident. Now the Earth is “a mote of dust suspended in a sunbeam.” That image evokes the idea of something that is nearly weightless and insubstantial, but which can be mesmerizing when viewed in the right light. In the next paragraph Sagan bemoans the scale of human violence and makes a direct appeal to the reader to consider “the endless cruelties visited by the inhabitants of one corner of this pixel on the scarcely distinguishable inhabitants of some other corner”. The insignificance of Earth from this distance conveys how petty attempts at conquest and domination The isolation of Earth against “the great enveloping cosmic dark” is presented as a reminder that we must save ourselves.

In the final two paragraphs of the chapter science returns as a tool for interpreting this new understanding of our position in the Cosmos. We know from experience that Earth is hospitable to life, and we know from science that there is no other world in which we can currently take refuge. While the later sections of the book Pale Blue Dot is about Sagan’s hopes for humanities future in space, he makes it clear at the beginning that “for the moment the Earth is where we make our stand.” Sagan calls astronomy a “humbling and character building process” and positions the Pale Blue Dot image as part of that process. Sagan concludes that the lesson he takes from the image is to be more kind to each other and to protect our only home.vii

Sagan sought out this photograph because he hoped it would provide this humbling perspective. He saw it as a continuation of the process of changing perspective begun by the whole Earth photographs returned by Apollo. I believe there is a qualitative, rather than merely quantitative difference between whole Earth and the Pale Blue Dot. Sagan recognizes the absences important to the whole Earth image: the lack of borders, and the inability to discern any signs of human civilization. He describes humans on this scale as “inconsequential, part of a thin film of life.”viii The absences that make the Pale Blue Dot meaningful convey new ideas that communicate Sagan’s Cosmic perspective. The inability to discern landmasses, oceans, the hint of green grasslands and forests, or clouds make Earth one, but not the only, blue world in our Solar System. The “thin film of life”, let alone humanity, can no longer be discerned. In the collection of images that include the Pale Blue Dot other worlds can be seen as other dots, but the distances between the dots are so great that no two appear in the same frame. Each is isolated against the vastness of space. This presents the Earth as far less significant than the frame filling Apollo photos. The Earth fills the frame of those photos, and so it is possible to imagine that the distance to the next hospitable world may not be so far. The Pale Blue Dot makes the isolation of the Earth explicit. The whole Earth diminishes human pride with its absence of borders and landmarks, but the Pale Blue Dot goes beyond obliterating pride to make us contemplate our isolation and vulnerability.

iCarl Sagan, Pale Blue Dot (New York: Random House, 1994), 1, Kindle

iiIbid. pp 2

iiiIbid. pp 4

ivIbid. pp 5

vIbid. pp 6

viIbid. pp 6

viiIbid. pp 7

viiiIbid. pp 3

Tags: Nuclear, Global, Air, Environmentalist, Popular Culture