Cosmic Connection (4 page)

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Authors: Carl Sagan

Tags: #Origin, #Marine Biology, #Life Sciences, #Life - Origin, #Science, #Solar System, #Biology, #Cosmology, #General, #Life, #Life on Other Planets, #Outer Space, #Astronomy

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Further binary numbers are shown in the radial pattern comprising the main part of the diagram at left center. These numbers, if written in decimal notation, would be ten digits long. They must represent either distances or times. If distances, they are of the order of several times 10
11
centimeters, or a few dozen times the distance between the Earth and the Moon. It is highly unlikely that we would consider them useful to communicate. Because of the motion of objects within the Solar System, such distances vary in continuous and complex ways.

However, the corresponding times are on the order of 1/10 second to 1 second. These are the characteristic periods of the pulsars, natural and regular sources of cosmic radio emission; pulsars are rapidly rotating neutron stars produced in catastrophic stellar explosions (see Chapter 38). We believe that a scientifically sophisticated civilization will have no difficulty understanding the radial burst pattern as the positions and periods of 14 pulsars with respect to the Solar System of launch.

But pulsars are cosmic clocks that are running down at largely known rates. The recipients of the message must ask themselves not only where it was ever possible to see 14 pulsars arrayed in such a relative position, but also
when
it was possible to see them. The answers are: Only from a very small volume of the Milky Way Galaxy and in a single year in the history of the Galaxy. Within that small volume there are perhaps a thousand stars; only one is anticipated to have the array of planets with relative distances as indicated at the bottom of the diagram. The rough sizes of the planets and the rings of Saturn are also schematically shown. A schematic representation of the initial trajectory of the spacecraft launched from Earth and passing by Jupiter is also displayed. Thus, the message specifies one star in about 250 billion and one year (1970) in about 10 billion.

The content of the message to this point should be clear to an advanced extraterrestrial civilization, which will, of course, have the entire
Pioneer 10
spacecraft to examine as well. The message is probably less clear to the man on the street, if the street is on the planet Earth. (However, scientific communities on Earth have had little difficulty decoding the message.) The opposite is the case with the representations of human beings to the right. Extraterrestrial beings, which are the product of 4.5 billion years or more of independent biological evolution, may not at all resemble humans, nor may the perspective and linedrawing conventions be the same there as here. The human beings are the most mysterious part of the message.

4. A Message to Earth

T
he golden greeting card placed aboard the
Pioneer 10
spacecraft was intended for the remote contingency that representatives of an advanced extraterrestrial civilization, some time in the distant future, might encounter this first artifact of mankind to leave the Solar System. But the message has had a more immediate impact. It has already been meticulously studied–not by extraterrestrials, but by terrestrials. Human beings all over the planet Earth have examined the message, applauded it, criticized it, interpreted it, and proposed alternative messages.

The graphics of the message have been reproduced widely in newspapers and television programs, small art and literary magazines, and national newsweeklies. We have received letters from scientists and housewives, historians and artists, feminists and homosexuals, military and foreign service officers, and one professor of bass fiddle. Our plaque has been reproduced for commercial sale by an engraving company, a distributor of scientific knickknacks, a manufacturer of tapestry, and an Italian mint specializing in silver ingots–all, incidentally, without authorization.

The great majority of comments have been favorable, some extraordinarily enthusiastic. The large street advertising billboards for the
Tribune
of Geneva, Switzerland, announced “
Message de la NASA pour les extraterrestres
!” One scientist writes to say that the description of the scientific basis of the plaque we published in the American journal
Science
was the first scientific paper he had ever read that moved him to tears of joy. A correspondent in Athens, Georgia, writes, “We’ll all be gone before this particular message in a bottle is picked up by some indescribable spacecomber; nevertheless, its very existence, the audacity of the dream, inevitably produces in me–and many others I know–the feelings of a Balboa, a Leeuwenhoek, a human being being human!”

At the California Institute of Technology, where the graffiti is arcane, some unknown artist drew the message life-size on a barrier at a building site, eliciting friendly greetings from the inhabitants, which we hope will serve as a model for extraterrestrial readers (see the illustration on the facing page).

But there were also critical comments. They were not directed at the pulsar map, which was the scientific heart of the message, but rather at the representation of the man and the woman. The original drawings of this couple were made by my wife and were based upon the classical models of Greek sculpture and the drawings of Leonardo da Vinci. We do not think this man and woman are ignoring each other. They are not shown holding hands lest the extraterrestrial recipients believe that the couple is one organism joined at the fingertips. (In the absence of indigenous horses, both the Aztecs and the Incas interpreted the mounted
conquistador
as one animal–a kind of two-headed centaur.) The man and woman are not shown in precisely the same position or carriage so that the suppleness of the limbs could be communicated–although we well understand that the conventions of perspective and line drawing popular on Earth may not be readily apparent to civilizations with other artistic conventions.

The man’s right hand is raised in what I once read in an anthropology book is a “universal” sign of good will–although any literal universality is of course unlikely. At least the greeting displays our opposable thumbs. Only one of the two people is shown with hand raised in greeting, lest the recipients deduce erroneously that one of our arms is bent permanently at the elbow.

Several women correspondents complain that the woman appears too passive. One writes that she also wishes to greet the universe, with both arms outstretched in womanly salutation. The principal feminine criticism is that the woman is drawn incomplete–that is, without any hint of external genitalia. The decision to omit a very short line in this diagram was made partly because conventional representation in Greek statuary omits it. But there was another reason: Our desire to see the message successfully launched on
Pioneer 10
. In retrospect, we may have judged NASA’s scientific-political hierarchy as more puritanical than it is. In the many discussions that I held with such officials, up to the Administrator of the National Aeronautics and Space Administration and the President’s Science Adviser, not one Victorian demurrer was ever voiced; and a great deal of helpful encouragement was given.

Yet it is clear that at least some individuals were offended even by the existing representation. The Chicago
Sun Times
, for example, published three versions of the plaque in different editions all on the same day: In the first the man was represented whole; in the second, suffering from an awkward and botched airbrush castration; and in the final version–intended no doubt to reassure the family man dashing home–with no sexual apparatus at all. This may have pleased one feminist correspondent who wrote to the New York
Times
that she was so enraged at the incomplete representation of the woman that she had an irresistible urge “to cut off the man’s … right arm!”

The Philadelphia
Inquirer
published on its front page an illustration of the plaque, but with the nipples of the woman and the genitalia of the man removed. The assistant managing editor was quoted as saying, “A family newspaper must uphold community standards.”

An entire mythology has evolved about the absence of discernible female genitalia. It was a column by the respected science writer Tom O’Toole, of the Washington
Post
, that first reported that NASA officials had censored an original depiction of the woman. This tale was then circulated in nationally syndicated columns by Art Hoppe, Jack Stapleton, Jr., and others. Stapleton imagined the enraged citizens of another planet receiving the plaque, and in a paroxysm of moral outrage covering over with adhesive tape the pornographic representation of the
feet
of the man and the woman. One letter writer to the Washington
Daily News
proposed that if the woman was to be censored, then for consistency the noses of the humans should have been painted blue. A tut-tutting letter in
Playboy
magazine complained about this further intrusion of government censorship, already quite bad enough, into the lives of the citizenry. Editorials in sciencefiction magazines also took the government to task. The idea of government censorship of the
Pioneer 10
plaque is now so well documented and firmly entrenched that no statement from the designers of the plaque to the contrary can play any role in influencing the prevailing opinion. But we can at least try.

What sexuality there is in the message also drew epistolary fire. The Los Angeles
Times
published a letter from an irate reader that went:
I must say I was shocked by the blatant display of both male and female sex organs on the front page of the
Times
. Surely this type of sexual exploitation is below the standards our community has come to expect from the
Times
. Isn’t it enough that we must tolerate the bombardment of pornography through the media of film and smut magazines? Isn’t it bad enough that our own space agency officials have found it necessary to spread this filth even beyond our own solar system?

This was followed several days later by another letter in the
Times
: I certainly agree with those people who are protesting our sending those dirty pictures of naked people out into space. I think the way it should have been done would have been to visually bleep out the reproductive organs of the drawings of the man and the woman. Next to them should have been a picture of a stork carrying a little bundle from heaven.
Then if we really want our celestial neighbors to know how far we have progressed intellectually, we should have included pictures of Santa Claus, the Easter Bunny, and the Tooth Fairy.

The New York
Daily News
headlined the story in typical fashion: “Nudes and Map tell about Earth to Other Worlds.”
Some correspondents argue that the function of the sexual organs would not be obvious even had they been graphically displayed, and urged on us a sequence of cartoons from copulation to birth to puberty to copulation. There was not quite room for this on a 6-inch by 9-inch plaque. I can also imagine the letters that would then have been written to the Los Angeles
Times
.

An article in
Catholic Review
criticizes the plaque because it “includes everything but God,” and suggests that, rather than a pair of human beings, it would have been better to have borne a sketch of a pair of praying hands.
Another correspondent maintains that the perspective conventions are insuperably difficult, and urges us to send the complete cadavers of a man and a woman. They would be perfectly preserved in the cold of space, and could be examined by extraterrestrials in detail. We declined on grounds of excess weight.

The front page of the Berkeley, California,
Barb
, apparently intending to convey an impression that the man and woman on the message were too straight, reproduced them with the caption, “Hello. We’re from Orange County.”

This comment touches on an aspect of the representation of the man and woman that I personally feel much worse about, although it has received almost no other public notice. In the original sketches from which the engravings were made, we made a conscious attempt to have the man and woman panracial. The woman was given epicanthian folds and in other ways a partially Asian appearance. The man was given a broad nose, thick lips, and a short “Afro” haircut. Caucasian features were also present in both. We had hoped to represent at least three of the major races of mankind. The epicanthian folds, the lips, and the nose have survived into the final engraving. But because the woman’s hair is drawn only in outline, it appears to many viewers as blond, thereby destroying the possibility of a significant contribution from an Asian gene pool. Also, somewhere in the transcription from the original sketch drawing to the final engraving the Afro was transmuted into a very non-African Mediterranean-curly haircut. Nevertheless, the man and woman on the plaque are, to a significant degree, representative of the sexes and races of mankind.

Professor E. Gombrich, the Director of the Warburg Institute, a leading art school in London, criticizes the plaque in the journal
Scientific American
. He wonders how the plaque can possibly be expected to be visible to an extraterrestrial organism that may not have developed the sense of sight at visible wavelengths. The answer is derived simply from the laws of physics. Planetary atmospheres absorb light from the nearby sun or suns because of three molecular processes. The first is a change in the energy state of individual electrons attached to atoms. These transitions occur in the ultraviolet, X-ray, and gamma-ray parts of the spectrum and tend to make a planetary atmosphere opaque at these wavelengths. Second, there are vibrational transitions that occur when two atoms in a given molecule oscillate with respect to each other. Such transitions tend to make planetary atmospheres opaque in the near infrared part of the spectrum. Third, molecules undergo rotational transitions, due to the free rotation of the molecule. Such transitions tend to absorb in the far infrared. As a result, quite generally, the radiation from the nearby star, which penetrates through a planetary atmosphere, will be in the visible and in the radio parts of the spectrum–the parts that are not absorbed by the atmosphere.

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