(Suit la biographie du Dr. Sagan: )
Le Dr. Carl Sagan est Professeur Adjoint en Astronomie au Centre de Radiophysique et de Recheche Spatiale de l'Université de Cornell, Ithaca, New York. Il a obtenu ses A. B. et B.S., une M. S. en Physique et son Ph. D. en Astronomie et Astrophysique, tous de l'Université de Chicago. Il a depuis tenu des positions à l'Université de Californie, Berkeley; à l'Ecole Médicale de l'Université de Stanford (en tant que Professeur Adjoint de Génétique); et à l'Université d'Harvard et à l'Observatoire Astrophysique Smithsonian.
Les principaux intérêts de recherche du Dr. Sagan sont sur la physique et la chimie des atmosphères et surfaces planétaires, l'origine de la vie sur Terre, et l'exobiologie. Il a joué un rôle primordial en établissant, par exemple, que la surface de Vénus est très chaude et que des grandes différences d'altitude existent sur Mars, et a été un principal exponent of the view that organic molecules are to be found on Jupiter.
Dr. Sagan a servi dans de nombreux groupes de conseil de l'Administration Nationale de l'Espace et de l'Aéronautique et de l'Académie Nationale des Sciences, ainsi que des organisations internationales telles que le COSPAR et l'International Astronomical Union. Il a été membre du Comité visant à réexaminer le Projet Blue Book pour le Comité de Conseil Scientifique de l'Armée de l'Air.
Lauréat du Prix Smith à Harvard en 1964 et Condon Lecturer dans l'Etat de l'Oregon en 1968, le Dr. Sagan is shortly to assume additional duties as Editor of the planetary sciences journal, ICARUS. He has been active in educational innovations, regularly teaches in the South, and is a lecturer in the astronaut training program in Houston.
En plus de bien plus d'une centaine d'articles scientifiques, et plusieurs articles écrits pour les Encyclopedias Britannica et Americana, le Dr. Sagan est co-auteur de The Atmospheres of Mars and Venus (1961), Planets (1966) et Intelligent Life in the Universe (1966).
Dr. Sagan. Merci beaucoup, Congressman Roush.
Tel que je le comprends ce que le comité voudrait de moi, c'est une discussion sur la probabilité de vie extraterrestre intelligente, et since this estimate is to be made in this symposium, clearly it is the hypothesis that unidentified objects are of extraterrestrial origin which the committee must have in mind.
I'm delighted to tell about contemporary scientific thinking along these lines, but let me begin by saying that I do not think the evidence is at all persuasive, that UFO's are of intelligent extraterrestrial origin, nor do I think the evidence is convincing that no UFO's are of intelligent extraterrestrial origin.
I think as each of the preceding speakers has mentioned, but perhaps not sufficiently emphasized, that the question is very much an open one, and it is certainly too soon to harden attitudes and make any permanent contentions on the subject.
I find that the discussion, like elsewhere, is best evaluated if we consider the question of life on earth. I suppose that if you had all your prejudices removed and were concerned with the question of whether the earth was populated by life of any sort, how would you go about finding out?
If, for example, we were on some other planet, let's say Mars, and looking at the Earth, what would we see? Fortunately we now have meteorological satellite photographs of the earth at various resolutions, so we can answer the question. The first large slide.
This is a photograph of the earth. That is the full earth, which you are looking at which is primarily cloud cover. This is the Pacific Ocean. You can see southern California in the upper right, and, as advertised by the local chamber of commerce, you can see it is cloud free. [Laughter.]
Dr. Sagan. Now, it is clear that very little information about the earth, much less possibility of life on it, is obtained by a picture at this resolution.
The next large slide is a TIROS photograph of the earth at about 1-mile resolution, that is, things smaller than a mile cannot be seen, and very prolonged scrutiny of the entire eastern seaboard of the United States shows no sign of life, intelligent, or otherwise.
We have looked at several thousand photographs of the earth, and you may be interested to see that there is no sign of life, not only in New York or Washington, but also in Peking, Moscow, London, Paris, and so on.
The reason is that human beings have transformed the earth at this kind of scale very little, and therefore the artifacts of human intelligence are just not detectable photographically in the daytime with this sort of resolution.
The next slide shows one of the few successful finds of intelligent life on earth that we made; down toward the lower left you can see a kind of grid, a kind of crisscross pattern, a rectangular area. This is a photograph taken near Cochran, Ontario, in Canada. What we are looking at are swaths cut by loggers through the forest. They cut many swaths in parallel, then another parallel sequence of swaths at right angles. Then the snow fell, heightening contrast, so that is the reason for the tic-tac-toe pattern. The sequence of straight lines there is anomalous. You would not expect it by geological processes. If you found that on another planet you would begin to expect there is life there. This is a photograph at about a tenth of a mile resolution, and is far better than the best photographs we have of Mars. The photographs we have of Mars are, of course, better than of any other planet. Therefore, to exclude intelligent life on another planet photographically is certainly premature. We could not exclude life on earth with this same sort of resolution.
However, there are other reasons why intelligent life on the other planets of this solar system are moderately unlikely.
To continue this sequence of photographs, I should say there are only about one in a thousand photographs where this resolution of the earth gives any sign of life.
The next photograph, however, shows a resolution about three times better. That is a Gemini capsule in the lower left-hand corner and we are looking at the vicinity of the Imperial Valley in California. You are just on the verge of resolving the contour patterns of fields, for agricultural purposes.
The next slide shows us an area between Sacramento and San Francisco, which has a very clear geometric pattern. It is quite obvious that this is the result of some intelligent activity on the earth.
You can see an airport, a railway, the monotonous pattern of housing developments in the upper right. You can see the patterns of contour fields. And this is such a highly geometrized picture, that it is clearly the result of some intelligence.
However, a photograph taken of this same area, only let's say 100,000 years ago, when there certainly was lots of life on earth, would show none of these features, because these are all the signs of our present technical civilization.
So even though the earth was full of life, and human beings were very much in evidence 100,000 years ago, none of this would be detectable by such photography. To detect individual organisms on earth, we have to have a photographic resolution about 10 times better than this, then we occasionally see things like these in the next slide. All those little dots casting shadows are cows in a field in California.
There are other ways of detecting intelligent life on the earth. From the vantage point of Mars, detecting, say, the lights of cities at night, is extremely marginal, and in fact the only way of doing it would be to point a small radio telescope at the earth, and then as the North American Continent turned toward Mars, there would be this blast of radio emission from domestic television transmission that prolonged scrutiny would indicate some sign of intelligent life on the earth.
In fact, it is radio communications which is the only reasonable method of communications over very large distances. It is a remarkable fact that the largest radio telescope on the earth at the present time, the Arecibo dish in Puerto Rico, is capable of communicating with another dish, similarly outfitted if one existed at the incredible distance of 1,000 light years away, a light year being about 6.6 trillion miles, and the distance to the nearest star being a little over 4 light years.
Now, let me then go to the question of the cosmic perspective of where we are.
We are, of course, sitting on a planet, the third from the Sun, which is going around the Sun, which is a star-like, and the other stars visible on a clear night to the naked eye.
The first small slide will give an impression of what happens when you point a moderate telescope in the direction of the center of the Milky Way Galaxy.
This is a photograph of a star cloud. You are looking at tens of thousands of suns here. In fact, the number of suns in our galaxy is about 150,000 million.
They are collected into a disk-shaped pattern, shown in the next slide; the next slide will show a photograph of the nearest galaxy like our own. That fuzzy spiral thing in the middle is M-31, that is also known as the Great Galaxy Andromeda, and if that were a photograph of our galaxy, we would be situated extremely far out, in fact, a little far off the slide, very much in the galactic boon docks. The Sun is nowhere near the center of the galaxy. It is a very out-of-the-way rural location we happen to be in.
Now, in [the] collection of 150,000 million stars in the Milky Way Galaxy, our sun is just one, and there are at least billions of other galaxies, and the last slide, will show you what happens if you point a telescope away from the obscuring dust and stars in the galaxy. You then start seeing dozens of other galaxies, everyone of those funny-shaped spiral and irregular-shaped things there, and some of the spherical-shaped ones, are other galaxies, each of which are containing about 100 billion stars as well.
So it is clear that there are in the accessible universe, some hundreds of billions of billions of stars, all more or less like our own.
Now, if we want to assess the likelihood that there are intelligent civilizations somewhere in advance of our own, on planets of other stars in our own galaxy, we have to ask questions which cover a variety of scientific subjects, some of which are fairly well known, some of which are extremely poorly known. For a numerical assessment of whether there is likely intelligence in other parts of the galaxy in a form we do not have at present, let me indicate the kinds of things we know. It depends on the rate of star formation.
It depends on the likelihood that the given star has planets. It depends on the likelihood at least one of those planets is at a position from the essential star which is suitable for the origin of life. It depends on the likelihood that the origin of life actually occurs on that planet. It depends on the probability life once arisen on that planet will evolve to some intelligence. It depends on the likelihood that intelligence, once emerged, will develop a technical civilization. And it depends on the lifetime of the technical civilization, because technical civilization of a very short lifetime, will result in very few technical civilizations being around at any given time. We know something about some of these. There is some reason to believe that planets are a reasonable likely accompaniment of star formation, that the solar system in other words is a fairly common event in the galaxy and is not unique. There are laboratory experiments on the origin of life, in which the early conditions on earth have been duplicated in the laboratory. It turns out that at least the molecules fundamental to living systems, are produced relatively easy [sic], physics and chemistry apparently made in such a way that the origin of life may be a likely event.
Beyond that it is difficult to do laboratory experiments, because evolution takes billions of years, and scientists aren't that patient. Therefore, it is just a question of intelligent and knowledgeable estimates.
Here, some scientists believe that the evolution of intelligence and technical civilization is very likely. Others believe it is a very remarkable and unusual event and by the merest fluke did it happen here.
I don't think that this is the place to go into this very difficult question in any great detail. Let me merely say that much more important than these uncertainties is the question of the life of a technical civilization, judging from the events on the earth, one might say the likelihood of our civilization lasting only a few decades more, might be a fairly high probability, and if that is typical of other civilizations, then it is clear there aren't any other humans around.
On the other hand, if civilizations tend to have very long lifetimes, it may be there are large numbers of technical civilizations in the galaxy.
Now, one thing is clear, which is this: If there are other technical civilizations, any random one of them is likely to be vastly in advance of our own technical civilization. For example, we are only 10 or 15 years into having the technology of interstellar communication by radio astronomy. It is unlikely there is any other civilization in the galaxy that is that backward in their technical expertise.
Mr. Miller. Doctor, didn't Sir Bernard Lovell receive electrical pulses he can't explain?
Dr. Sagan. Yes, sir. There are now five objects in the heavens called pulsars, which are objects which are sending out radiation which is modulated with a frequency of about one per second; also there are sub-modulations. There are a variety of hypotheses to explain these things, some of which involve the oscillations of very old stars. There are certain difficulties with each hypothesis. The first suggestion made by the British at Cambridge, when they encountered this phenomenon was perhaps it was a beacon of some extraterrestrial civilization. That is not now their favored hypothesis. It is not clear that that is totally absurd, but in fact the scientific method to be used in that case is rather similar to the one to be used in this case. That is, it is a puzzling phenomenon. One therefore excludes all physical explanations that one possibly can before going to the much more hypothetical possibility of intelligence being involved.
So, that is the present state of work in that field. For data gathering to get better information, and the refinement of the purely physical hypothesis.
Well, I was saying that if there are other civilizations, many of them are likely to be far in advance of our own, and this, therefore, raises the question of how likely it is that they can traverse interstellar space and come from planets or some other star to here.
I should first emphasize that the distances between the stars are absolutely huge. Light, faster than which nothing can travel, takes 4½ years to get from here to the nearest star.
Mr Roush. Excuse me, isn't that a rather arbitrary statement?
Dr. Sagan. I don't think so. Perhaps you can tell me why you think it might be, then I can tell you why I think it isn't.
Mr. Roush. In my opening statement I referred to the new audacity of imagination John Dewey had spoken of. I'm thinking of imaginative terms, not factual terms.
Dr. Sagan. Let me say in a sentence, why most physicists believe no material object can travel faster than light. That takes us into questions of the theory of relativity, which has had previous encounters with congressional committees, and perhaps we don't want to go into that in very great detail.
But the essential point is, that in making a few, very few assumptions, one of which was, the one we are talking about, nothing goes faster, Einstein was able to then derive a whole body of predictions which are confirmed in vast detail. Therefore, if someone says that is not a good idea, that things can travel faster than light, then they have to come up with a physical theory which explains everything we know in a way that is consistent with the idea that you can travel faster than light. No one has succeeded in doing that. Many physicists have tried. Therefore, the present belief is that you can't. But that, of course, is a time-dependent statement. It may be that this isn't the ultimate truth.
In physics, as in much of all science, there are no permanent truths, There is a set of approximations, getting closer and closer, and people must always be ready to revise what has been in the past thought to be the absolute gospel truth. If I might say, to revise opinions, is one which is frequent in science, and less frequent in politics. [Laughter.]
Dr. Sagan. So, in the context of contemporary science, I'm obviously speaking in that context, one cannot travel faster than light.
So the distances between the stars are extremely large. Of course, any contemporary space vehicle would take a ridiculous amount of time to get from here to anywhere else, but we are not talking about contemporary space vehicles. The question, "Is there any conceivable method of traveling from one place to another very close to the speed of light, and therefore get reasonable transit times?" involves extrapolations of technology of a very difficult sort. However, let me merely say at least some people who have looked into the subject have concluded that it is not out of the question, even with contemporary principles of science, to imagine vehicles capable of traveling close to the speed of light, between the stars.
This doesn't mean that it happens. There may in fact be insuperable engineering difficulties we don't know about, but there is nothing in the physics that prohibits interstellar space flight.
So any estimate of how likely it is that we would be visited by an extraterrestrial intelligent civilization, depends not only on how many of them are there, but on what kind of transport they have, and how often they launch their space vehicles, even very optimistic estimates for all these numbers, gives a conclusion that an advance civilization comes here very rarely. But I again emphasize the great uncertainty in any of these numerical estimates, as they involve parts of science we don't know very much about.
So, to conclude what I understand is the main reason why this committee has asked me to testify, it is not beyond any question of doubt that we can be visited. There are great difficulties from our present point of view. They are not insuperable. And if Dr. McDonald, for example, were to present me with extremely convincing evidence of an advanced technology in a UFO, I could not say to him that is impossible, because I know you can't get from there to here, or I can't say to him that is impossible because I know there aren't any other guys up there.
On the other hand, I would of course demand very firm evidence before I would say, well, that seems to be a very likely hypothesis. So I would like to spend Just a few minutes to come more closely to the subject of this symposium.
First of all, I think it is clear to the committee, but this point should be emphasized very strongly, that there are very intense, predisposing, emotional factors in this subject.
There are individuals who very strongly want to believe that UFO's are of intelligent extraterrestrial origin. Essentially to my view, for religious motives; that is, things are so bad down here, maybe somebody from up there will come and save us from ourselves. This takes all sorts of subtle and not so subtle forms. There are also predisposing emotional factors in the other direction; people who very much want to believe UFO's are not of intelligent extraterrestrial origins, because that would be threatening to our conception of us as being the pinnacle of creation. We would find it very upsetting to discover that we are not, that we are just a sort of two-bit civilization.
It is clear that the scientific method says you don't take either of those views, and you simply keep an open mind and pursue whatever facts are at hand with as many diverse hypotheses as possible, and try to eliminate each suggested hypothesis, and see if you are lucky with any one.
I might mention that, on this symposium, there are no individuals who strongly disbelieve in the extraterrestrial origin of UFO's and therefore there is a certain view, not necessarily one I strongly agree with -- but there is a certain view this committee is not hearing today, along those lines.
Finally, let me say something about the question of priorities, which Congressman Rumsfeld asked us for, and the question of significance. Now, the possibility of discovering something about extraterrestrial life, life originated on some other planet, is of the very highest interest for biology and in fact for all science. A bona fide example of extraterrestrial life even in a very simple form, would revolutionize biology. It would have both practical and fundamental scientific benefits, which are very hard to assess, it would truly be immense.
Now, if the answer to this sort of profound scientific question lies right at hand, it would be folly to ignore it. If we are being visited by representatives of extraterrestrial life, just stick our heads in the sand, would be a very bad policy, I think.
On the other hand, to mount a major effort to investigate these things, I think requires some harder evidence than is now at hand.
It is clear that if such an effort were mounted, some information on atmospheric physics would be forthcoming. I think some information on psychology would certainly be forthcoming. I have the impression that the capability of human populations to self-delusion, has not been accorded appropriate weight in these considerations. There is an interesting book published about a century ago by McKay called "Extraordinary Popular Delusions and the Madness of Crowds" which I commend to the committee. It goes into such things as alchemy, and witchcraft. After all, there have been centuries in which these things were considered to be as obviously true as anything, and yet we now know that this is really nonsense.
So the possibility of these sort of delusions having a kind of contemporary guise as UFO's should not be thrown out altogether. I do not think that explains most or all of the unidentified settings.
Since the funds are so painfully tragically short for science today, the priority question boils down to this: In the search for extraterrestrial life there is a high risk, high possibility, that is the one we are talking about today; namely, UFO's -- there is a high risk that they are not of extraterrestrial origin, but if they are, we are sure going to learn a lot.
Compared to that, there is a moderate risk, significant return possibility, and that is, looking for life even simple forms on nearby planets, and searching for intelligent radio communications by the techniques of radio astronomy. Here it is clear there will be significant paydirt of one sort or another for what I gather is a comparable sort of investment.
So if Congress is interested, and I'm not sure it is, I think it might very well ought to be, but if Congress is interested in a pursuit of the question of extraterrestrial life, I believe it would be much better advised to support the biology, the Mariner, and Voyager programs of NASA, and the radio astronomy programs of the National Science Foundation, than to pour very much money into this study of UFO's.
On the other hand, I think a moderate support of investigations of UFO's might very well have some scientific paydirt in it, but perhaps not the one that we are talking about today.
Mr. Chairman that concludes my statement except that I request that you include for the record a statement entitled "Unidentified Flying Objects" that I prepared for the Encyclopedia Americana.
(par Carl Sagan)
Objet Volant Non Identifié (OVNI*s [In Encyclopedia Americana (New York: Grolier) and In Bull Atom. Sci, 23, (6), 43, 1967.]) est le terme générique pour les phénomènes aériens ou célestes en déplacement, détectés visuellement ou par radar, dont la nature n'est pas immédiatement comprise. L'intérêt pour ces objets va de la spéculation que certains d'entre eux sont les produits de civilisations au-delà de la Terre, et des réfléxions psychologiques sur les problèmes humains comtemporains que cette interprétation, fournit.
Observations. Unidentified flying objects have been described variously as rapidly moving or hovering; disc-shaped, cigar-shaped, or ball-shaped; moving silently or noisily; with a fiery exhaust, or with no exhaust whatever; accompanied by flashing lights, or uniformly glowing with a silvery cast. The diversity of the observations suggests that UFO's have no common origin and that the use of such terms as UFO's or "flying saucers" serves only to confuse the issue by grouping generically a variety of unrelated phenomena.
In the United States, popular interest in unidentified flying objects began on June 24, 1947, when a group of rapidly moving, glistening objects was observed from the air in daytime, near Mount Rainier, Washington. The observer, a Seattle resident, dubbed them "flying saucers." The sighting received extensive publicity. Somewhat similar sightings have been reported ever since. The differences among these observations, however, are as striking as the observations themselves.
Investigations. Because of its national defense responsibility, the U.S. Air Force investigates reports of unidentified flying object over the United States. The number of sightings investigated in 1947-65 is shown in the following table.
Evaluation of these reports is difficult. Observations frequently are sketchy, and different reports of the same phenomenon are often dissimilar, or even irreconcilable. Observers tend to exaggerate. Deliberate hoaxes, some involving double-exposure photography, have been perpetrated. After allowances are made for these factors, the accepted scientific procedure is to attempt an explanation of the observations in terms of phenomena independently observed and understood. Only if an observation is rigorously inexplicable in terms of known phenomena does the scientist introduces alternative hypotheses for which there is no other evidence. Such hypotheses must still be consistent with all other available scientific information.
The identity of most UFO's has been established as belonging to one of the following categories: unconventional aircraft; aircraft under uncommon weather conditions; aircraft with unusual external light patterns; meteorological and other high-altitude balloons; artificial earth satellites; flocks of birds; reflections of searchlights or headlights off clouds; reflection of sunlight from shiny surfaces; luminescent organisms (including one case of a firefly lodged between two adjacent panes of glass in an airplane cockpit window); optical mirages and looming; lenticular cloud formations; ball lighting; sun dogs; meteors, including green fireballs; planets, especially Venus; bright stars; and the aurora borealis.
Radar detection of unidentified flying objects has also occurred occasionally. Many of these sightings have been explained as radar reflections from temperature inversion layers in the atmosphere and other sources of radar "angels."
Considering the difficulties involved in tracking down visual and radar sightings, it is remarkable that all but a few percent of the reported UFO's have been identified as naturally occurring -- if sometimes unusual phenomena. It is of some interest that the UFO's which are unidentified do not fall into one uniform category of motion, color, lighting, etc., but rather run through the same range of these variables as the identified UFO's. In October 1957, Sputnik I, the first earth-orbiting artificial satellite, was launched. Of 1,178 UFO sightings in that year, 701 occurred between October and December. The clear implication is that Sputnik and its attendant publicity were responsible for many UFO sightings.
Earlier, in July 1952, a set of visual and radar observations of unidentified flying objects over Washington, D.C., caused substantial public concern. Government concern was reflected in the creation in November of that year of a special panel to evaluate these reports. The panel was established by the Office of Scientific Intelligence of the Central Intelligence Agency, and was headed by the late Professor H. P. Robertson of the California Institute of Technology. The Robertson panel, after a thorough investigation of the UFO reports to that date, concluded that all were probably natural phenomena, wrongly interpreted.
The most reliable testimony is that of the professional astronomer. Professor Jesse L. Greenstein of Mount Wilson and Palomar Observatories (author of the ASTRONOMY article on pages 90-95) has pointed out that a vehicle 100 feet (30.5 meters) in diameter, at an altitude of 50 miles (80.5 km), would leave a broad track on photographic plates of the sky taken with large telescopes. This track could be distinguished easily from those of ordinary astronomical objects such as stars, meteors, and comets. Nevertheless, it appears that such tracks or unambiguous visual observations of classical UFO's have never been made by professional astronomers.
For example, in the Harvard Meteor Project performed in New Mexico during the period 1954-56, extensive photographic observations were made by Super-Schmidt cameras, with a 60° field of view. In all, a surface area of about 3,000 square miles (7,700 sq km) was observed to a height of about 50 miles (80 km) for a total period of about 3,000 hours. Visual and photographic observations were made which could detect objects almost as faint as the faintest objects visible to the naked eye. These observations by professional astronomers were made in a locale and period characterized by extensive reports of unidentified flying objects. No unexplained objects were detected, despite the fact that rapidly moving objects were being sought in a study of meteors. Similar negative results have been obtained by large numbers of astronomers and help to explain the general skepticism of the astronomical community towards flying saucer reports.
A series of puzzling and well-published flying saucer sightings in the mid-1960's again led to the appointment of a government investigating panel, this time under the aegis of the Air Force Scientific Advisory Board. It is significant that this panel was convened not at the request of the operational or intelligence arms of the Air Force, but in response to a request by the Air Force public relations office. The panel, under the chairmanship of Brian O'Brien, a member of the board, met in February 1966, and restated the general conclusions of the Robertson panel. It was recommended that the Air Force make a more thoroughgoing effort to investigate selected UFO reports of particular interest. although the probability of acquiring significant scientific information (other than psychological) seemed small. The O'Brien panel suggested that the Air Force establish a group of teams at various points within the United States in order to respond rapidly to UFO reports. The panel recommended that each team should consist of a physical scientist familiar with upper atmospheric and astronomical phenomena, a clinical psychologist, and a trained investigator.
In October 1966 the University of Colorado was selected by the Air Force Office of Scientific Research to manage the program, and to prepare a thoroughgoing analysis of the UFO problem. The National Academy of Sciences agreed to appoint a panel to review the report when it is completed in early 1968.
Hypotheses of Extraterrestrial Origin. Repeated sightings of UFO's, and the persistence of the Air Force and the responsible scientific community in explaining away the sightings, have suggested to some that a conspiracy exists to conceal from the public the true nature of the UFO's. Might not at least a small fraction of the unexplained few percent of the sightings be space vehicles of intelligent extraterrestrial beings observing the earth and its inhabitants?
It now seems probable that the earth is not the only inhabited planet in the universe. There is evidence that many of the stars in the sky have planetary systems. Furthermore, research concerning the origin of life on earth suggests that the physical and chemical processes leading to the origin of life occur rapidly in the early history of the majority of planets. From the point of view of natural selection, the advantages of intelligence and technical civilization are obvious, and some scientists believe that a large number of planets within our Milky Way galaxy -- perhaps as many as a million -- are inhabited by technical civilizations in advance of our own.
Interstellar space flight is far beyond our present technical capabilities, but there seem to be no fundamental physical objections to it. It would be rash to preclude, from our present vantage point, the possibility of its development by other civilizations. But if each of, say, a million advanced technical civilizations in our galaxy launched an interstellar spacecraft each year (and even for an advanced civilization, the launching of an interstellar space vehicle would not be a trivial undertaking), and even if all of them could reach our solar system with equal facility, our system would, on the average, be visited only once every 100,000 years.
UFO enthusiasts have sometimes castigated the skeptic for his anthropocentrism. Actually, the assumption that earth is visited daily by interstellar spacecraft is far more anthropocentric -- attaching as it does some overriding significance to our small planet. If our views on the frequency of intelligence in the galaxy are correct, there is no reason why the earth should be singled out for interstellar visits. A greater frequency of visits could be expected if there were another planet populated by a technical civilization within our solar system, but at the present time there is no evidence for the existence of one.
Related to the interstellar observer idea are the "contact" tales, contemporary reports of the landing of extraterrestrial space vehicles on earth. Unlike the UFO reports, these tales display a striking uniformity. The extraterrestrials are described as humanoid, differing from man only in some minor characteristic such as teeth, speech, or dress. The aliens -- so the "contactees" report -- have been observing earth and its inhabitants for many years, and express concern at "the present grave political situation." The visitors are fearful that, left to our own devices, we will destroy our civilization. The contactee is then selected as their "chosen intermediary" with the governments and inhabitants of earth, but somehow the promised political or social intervention never materializes.
Psychological Factors. The psychologist Carl Jung pointed out that the frequency and persistence of these contact tales -- not one of which has been confirmed by the slightest sort of objective evidence -- must be of substantial psychological significance. What need is fulfilled by a belief that unidentified flying objects are of extraterrestrial origin? It is noteworthy that in the contact tales, the spacecraft and their crews are almost never pictured as hostile. It would be very satisfying if a race of advanced and benign creatures were devoted to our welfare.
The interest in unidentified flying objects derives, perhaps, not so much from scientific curiosity as from unfulfilled religious needs. Flying saucers serve, for some, to replace the gods that science has deposed. With their distant and exotic worlds and their pseudoscientific overlay, the contact accounts are acceptable to many people who reject the older religious frameworks. But precisely because people desire so intensely that unidentified flying objects be of benign, intelligent, and extraterrestrial origin, honesty requires that, in evaluating the observations, we accept only the most rigorous logic and the most convincing evidence. At the present time, there is no evidence that unambiguously connects the various flying saucer sightings and contact tales with extraterrestrial intelligence.
Jung, Carl G., Flying Saucers: A. Modern Myth of Things Seen in the Skies (New York 1959).
Menzel, D. H. and Boyd, L. G., The World of Flying Saucers: A. Scientific Examination of a Major Myth of the Space Age (New York 1963).
Ruppelt, Edward J., The Report on Unidentified Flying Objects (New York 1956).
Shklovsky, Iosif S. and Sagan Carl, Intelligent Life in the Universe (San Francisco 1966).
Tacker, Lawrence J., Flying Saucers and the U.S. Air Force (Princeton 1960).
Vallee, Jacques, Anatomy of a Phenomenon (Chicago 1968).
Mr. Hechler. Dr. Sagan, there have been some recent experiments at Green Bank, W. Va., with its 300-foot telescope, in an attempt to synchronize this with the Arecibo dish, in such a way as you might in effect produce almost a 2,000-mile diameter collecting surface for trying to receive signals from the pulsars.
I wonder if this isn't the type or specific activity in radio astronomy that could utilize some additional support in order to ascertain the truth about terrestrial life and signals therefrom ?
Dr. Sagan. Congressman Hechler, as a member of the faculty at Cornell that runs the observatory, I would find some problem answering that.
Mr. Hechler. But not of West Virginia, however?
Dr. Sagan. That is right. The study of pulsars, as I indicated to Chairman Miller, is relevant. The development of a long base-line parameter of the sort you talked about is of great interest to many areas of radio astronomy, and conceivably to the area we are talking about.
However, there has not been since Project OXMA, which occurred in Green Bank some 7 years or so ago, any systematic effort in this country to look for signals of intelligent extraterrestrial origin.
There is at the present time a fairly major effort under way in the Soviet Union, but at least in this country there are no such efforts directed specifically to this question.
It may be if we ever do detect intelligent signals from elsewhere, it will be an accidental byproduct of some other program. There is at the present time no effort to search for extraterrestrial signals.
Chairman Miller. Are they trying to do things in Australia?
Dr. Sagan. To the best of my knowledge there is no such work being done.
Chairman Miller. The Mills-Cross program is also connected with Cornell, isn't it?
Dr. Sagan. The Cornell-Sydney Astronomy Center, yes, sir.
Chairman Miller. Is that all, Mr. Hechler?
Mr. Hechler. I was hoping you would suggest something more specific, for our future consideration.
Dr. Sagan. Let me say, and again let me emphasize that it is by no means demonstrated that radio astronomical searches for extraterrestrial intelligence have anything whatever to do with UFO's, but if we were interested, as some of us are, in examining the possibility of extraterrestrial intelligence, sending signals to Earth, then relatively modest programs, of say less than a, million dollars, could be organized, using largely existing instruments with only small modifications in the things you hook up to the radio telescope, which would be ideal for this purpose.
There are in fact many radio astronomers who are privately interested in this sort of thing, but it carries something of the same sort of stigma that both the previous speakers mentioned about UFO's. It is unconventional. It is in many senses radical. Many astronomers prefer to have nothing to do with it.
Mr. Pettis. Mr. Chairman.
Mr. Roush. Mr. Pettis.
Mr. Pettis. I would like to ask the doctor, or any other member of the panel. Is there any indication that any other Government, particularly the Russians, are interested in this subject?
Dr. Sagan. I cannot speak about the UFO program. Perhaps Dr. Hynek can say something about that. As far as the question that I just mentioned, the radio search for extraterrestrial intelligence, there is a state commission in the Soviet Union, for the investigation of cosmic-radio intelligence. There is a fairly major effort that has been mustered for the last few years along these lines.
And there is only some information about that; that we have gotten out of the Soviet Union.
I don't know anything about their activities on UFOs. Perhaps Dr. Hynek would like to comment on that.
Dr. Hynek. May I, Mr. Chairman, preface my remark, in answer to that, by pointing out a danger here that we may be putting the cart before the horse in the consideration of extraterrestrial intelligence.
Speaking of horses, suppose someone comes here and tells us, or announces to us there is a report of a horse in the bath tub.
I think that it would be rather pointless to then ask, what is the color of the horse, what does he eat, how could be have gotten there, who installed the bath tub? The question is is there a horse in the bath tub? This is a question I think we should direct ourselves to first. Is there anything to these reports?
Now, coming to the question of the Russian situation, I do know from my visits behind the Iron Curtain, or as they like to speak of it, the Socialist countries, there have been sightings behind the Iron Curtain.
In fact, if you were to have good translations, it would be difficult to distinguish between a UFO report from Russia, from Brazil, from Argentina, from Japan, or from the United States. There is a rather rough pattern.
Now, the Russians, to the best of my knowledge, have given no official recognition to the problem, but I do know, from personal information, that there is sort of a ground-swell interest, or a latent interest, that pops up here and there, but apparently they have as much difficulty in getting official recognition as we do.
Mr. Roush. I would first point out that I realize that a visit to Russia doesn't necessarily make a person an expert or give him all the information. A year ago June I did visit Russia. I had conversations with a few of their people, including, my pronunciation may not be correct, Dr. Millionshchikov and the head of their weather bureau, I believe it is Petrov, and several others, and I repeatedly asked the question, "Do you believe in unidentified flying objects" In each instance they merely laughed. That was the response that I got. Since then, however, I have observed there have been papers published in Russia discussing the phenomena, and discussing it in scientific terms.
It seems to me that any discussion such as ours today raises the question of the existence of extraterrestrial life. That is one reason we asked Dr. Sagan to come here. I'm not real sure, Dr. Sagan, whether you stated whether there is or whether there is not extraterrestrial life. I was watching for that, and I don't believe I heard you say it.
Dr. Sagan. Congressman Roush, I have enough difficulty trying to determine if there is intelligent life on Earth, to be sure if there is intelligent life anywhere else. [Laughter.]
If we knew there was life on other planets, then we would be able to save ourselves a lot of agony finding out. It is just because the problem is so significant, and we don't have the answers at hand we need to pursue the subject. I don't know. It beats me.
Roush : I believe you coauthored a book with a Russian, is that correct?
That is correct.
Roush :Does Dr. Shklovsky share your views?
I think he shares my restraint.
I think both of us would say we think this is an extremely important subject, that we are on the frontier of being able to find out, but that neither of us knows whether there is or isn't life out there. Let me say if it turns out there isn't life on Mars, that is almost as interesting as if we find there is life on Mars, because then we have to ask, what happened different on Mars than on the Earth, so that life arose here and not there. That will surely give us a very profound entry into the question of follow-up of evolution and the cosmic context.
Roush :Suppose we discover there is life on Mars, in some form, wouldn't this almost cinch your case, and you could say there is extra-terrestrial life?
Yes, sir; it certainly would, but not cinch our case about extraterrestrial intelligence. Conceivably, there might be a low form on Mars. If there is Martian life, it is of interest how low it is. If there is intelligence on Mars -- but we don't know there is intelligence on Mars -- then we don't have to grasp that evolution process.
Roush :I would like to finish this mornings session just by telling of a cartoon I saw which I think Dr. Hynek perhaps saw and enjoyed as much as I did. It showed a flying saucer hovering over the Earth, with little green men looking down, and one turned to the other and said, "Do you suppose it is swamp gas?" [Laughter.]
Dr. Hynek. That is a good statement to close the session on.
Roush :We shall reconvene at 2 o'clock this afternoon.
(Là où, à 12 h 15, l'audition fut recessed to reconvene à 14 h)