History & Culture
From the Archives:
An Interview with Carl Sagan
In a series of articles published in Mercury during the 1970s, the then-editor interviewed some of the most-known researchers in astronomy. This is one of those interviews.
By Richard Reis
NASA/JPL-Caltech
Editor's note: This interview is a reprint, and originally appeared in Mercury's first decade. Thank you to Vandana Kaushik for the archival help.
Carl Sagan is the 1974 recipient of the Astronomical Society of the Pacific's Dorothea Klumpke-Roberts Award for outstanding contribution to public understanding of astronomy. On a recent trip to Los Angeles, Sagan met with Mercury editor, Richard Reis, to discuss the problems of both interstellar and interhuman communication, the need for a greater reliance on rationality, the current anti-science movement, and his own research efforts in planetary science.
Reis: One of the things I like about The Cosmic Connection is that in it you show yourself to be a divergent thinker willing to speculate publicly on subjects that interest you. In your book you discuss a very interesting situation in which the New Guinea natives communicate with neighboring societies by means of runners and drums, unaware of the advanced radio and cable traffic that passes around and through them. You state that an equally more advanced form of communication may be taking place around and through us, but we aren't able to detect it. What might these advanced forms of communication be?
Sagan: Like the New Guinea natives our perspective is constrained. Radio is the best that we can imagine. Suppose it were possible to use tachyons for communication. Since tachyons are particles which can never travel as slow as the speed of light, you might imagine being able to transmit a message in less than the light travel time. But most physicists think that is impossible.
There's probably no such thing as a a tachyon telescope because of the severe causality problems its use would imply. Of course that's an argument from analogy. Around here causes always precede effects, and not the other way around. Elsewhere I suppose there may be cases where effects precede causes. But this very discussion illustrates our limitations in conceiving a science and technology far beyond our own.
Reis: What about communication other than remote?
Sagan: To transmit a radio message, both sender and receiver must have radio technology. But suppose you're interested in close-up examination of supernovae remnants, or you want to look at the biology of planets which have not yet evolved to technical societies. Then radio communication does not do you much good, and you might be interested in interstellar space flight. Here the thing which is most striking is how much more difficult and expensive interstellar space flight is than radio communication. I don't believe it's impossible. Even today we can think of some schemes which, although ruinously expensive, defy no laws of physics and permit travel over interstellar distances in relatively short periods of time.
Reis: You also talk about the idea of time travel, in particular the problem of traveling backwards in time. If such time travel were possible, wouldn't we know it by now since we should have been visited in the present by people in our future?
Sagan: The same question can be asked about interstellar space flight. Shouldn't we know it by now because we should have been visited by beings from somewhere else? In both cases I would say it does not follow. For example, an advanced society could surely make a surveillance without the primitives knowing about it.
Reis: I suppose they would also be concerned about casualty as well.
Sagan: It’s to the advantage of time travelers not to alter events. But the causality problem may make travel backwards in time impossible.
Reis: On the other hand, travel into the future presents a different situation. Relativity allows us to go away and come back to an earth that's much older. Would you be interested in making such a trip?
Sagan: Sure.
Reis: Would you go tomorrow?
Sagan: I can’t imagine a more exciting adventure, simultaneously exploring space and time. One of the things I always wonder about is how this 20th Century is going to turn out. I'd love to have a chance to know.
Carl Sagan is perhaps most well-known among the public as a result of the Cosmos television series. This photograph captures him on set during one episode.
[Castaneda, E. (1981) Carl Sagan with the planets. , 1981. [Photograph] Retrieved from the Library of Congress]
Reis: I know you are very concerned about that. What do you see as the biggest problem we face in getting through the next hundred years?
Sagan: Stupidity and ignorance. One of our main problems is that our emotions are extremely well adapted to the world of 100,000 B.C. But we don't live in 100,000 B.C.; we live now. Many of the most powerful human emotions are inappropriate and even suicidal for the times we live in. This doesn't mean emotions should or could be placed aside. We would be mere mechanical men and women without feelings. But a much greater reliance on rationality is necessary if we are going to survive.
Consider overpopulation. Some of the most severe objections to birth control are on grounds which made considerable sense back when there were uncomfortably few human beings on the planet. But these objections are a serious impediment to human survival. Yet strong personal and institutional objections toward birth control continue.
Reis: Are you advocating genetic control?
Sagan: No, I’m advocating better education.
Reis: But if our emotions are really out of date, might not some kind of a chemical breakthrough take care of these things?
Sagan: Yes, but who administers the chemicals? Governments like those we've seen in this country lately? I would be more fearful about genetic or chemical control of the population by such governments than about control by the population itself. By 2050 the outline of the answer will be clear. Either we will have starved or polluted or irradiated ourselves to death, or we will have rationally used our intellectual abilities and global resources in a way to insure an agreeable life for the entire population of the planet. Whatever the configuration of the solution, I think it will be in hand by 2050.
Reis: In a sense you seem to be talking about some kind of a global understanding.
Sagan: That’s true. Consider the problem of national rivalries, of having a nation state as the object of one's self-identification. Imagine I'm all for the Slobovians, I cry with patriotic fervor when I see the Slobovian national flag and when I hear the Slobovian national anthem, and I'm out to get those rascally anti-Slobovians who live next door. Suppose that's the orientation I have. That's madness. The world is rapidly becoming an economic and cultural unity. Our identification ought to be with human beings over the whole planet, a global economy of the planet earth and the happiness of human beings everywhere.
I don't see much sign of that developing. In fact there are signs of the opposite happening, countries fragmenting into smaller tribal groups, as in Great Britain, for example. Where do we hear about the need for global identification? Where are the role models and the statesmen who tell us our fundamental identification ought not to be with individual racial, ethnic, religious or national groups, but with the planet as a whole? There's no country in which that's a widely held belief. Until it is, I think we face disaster.
Reis: You say that we need to be more rational?
Sagan: By that I mean we have to advertise more widely the joys and powers of rationalism. It isn't perfect, but it's the best we have. We cannot abandon technology; the lives of billions of people depend on it. We are stuck, like it or not, with high technology; and that immediately means we desperately need a widespread understanding of and appreciation for science and technology. That's a kind of parochial sense in which rationalism is necessary. More importantly, it works. It is the problem-solving method par excellence.
Reis: There are people who would argue that technology really hasn't been all that successful It has brought us many problems. Perhaps there is a way either around or beyond science.
Sagan: There may be, but there's no sign of it yet. And all of the alternatives that I know of just don't work. They have no external validation.
Reis: Do you see any conflict between your support for unmanned missions to Mars and Jupiter and the view that we should be spending more money here at home? After all the Viking project is a billion dollar mission.
Sagan: Finding out where we are and who we are and if there's anyone else out there is money well-spent. But there's no question that there is a phenomenal waste of money, with the defense budget as one clear example.
Astronomer Carl Sagan posed next to a model of the Viking lander in Death Valley, California. He was involved with NASA's Viking missions to Mars, which carried the first spacecraft to successfully soft-land on the martian surface.
[NASA]
Reis: Do you see any connection between the rise in mysticism and the popularity of astronomy lectures?
Sagan: The props of many traditional religions have been apparently undercut by the findings of science. And that same science opens up some other, to my mind more exciting, vistas than many of the religions. The decline of the one world view and the rise of the other are both connected with the evolution of science. That's one reason that some people are unhappy with science. It's helped to destroy a familiar and cozy arrangement with a human-centered universe and replaced it with a universe that is, at least so far, fundamentally indifferent to the existence and aspirations of mankind.
At the same moment, there arise a number of pseudo-scientific belief systems, such as UFO contact societies and the works of Erich von Daniken. The traditional religious beliefs can be dressed in modern scientific clothing and appear superficially plausible in a way that many traditional religions do not. Instead of talking about angels, they talk about beings from other planets wearing long white robes.
Reis: What kind of reaction have you received from your scientific colleagues? You're familiar with the notion that scientists shouldn't spend a lot of their time talking to the public.
Sagan: The times are changing. A great many scientists are now aware that continuing public support for science requires public understanding of science, and the public is not going to acquire such understanding if scientists aren't communicating it.
Reis: The self preservation approach?
Sagan: For the most selfish reasons, scientists ought to be extremely active in saying what's good about science. If scientists won't do that, who will?
Reis: But I take it that you are not doing it just for self preservation.
Sagan: No, absolutely not. I'm doing it fundamentally because I enjoy it. I get great satisfaction from interesting an audience in what I'm already turned on to. All my life I've been talking about astronomy and exobiology to whoever will listen. Lately there are somewhat larger audiences listening. But you asked originally not about my motivation but the motivations of others, and I think that even very stodgy scientists are aware that there is an ethical responsibility as well as a self-serving motive to explain what they're doing.
Carl Sagan was one of hte founders of the Planetary Society. That founding occured in 1980, several years after this interview appeared in Mercury.
[NASA]
Reis: Don’t people have the right to know what's going on in science?
Sagan: Absolutely, and the once common idea that it's too hard for the public to understand and so the hell with them is a great mistake. Almost all of science can be explained, by people who thoroughly understand the subject, in a way that the public can grasp.
There are so few areas of life where we see, for example, reasonable alternative arguments peaceably confronting each other. Science is the one field where that happens fairly often. Two conflicting theories or models of a given situation are presented and the determination of which is valid requires an experiment. You perform the experiment without too much prejudice, with the idea that nature is the ultimate arbiter. That's an approach which I would love to see widely accepted in politics and economics and in the organization of society in general.
Reis: In that sense, when you talk about this method, you feel that you are making a contribution.
Sagan: The entire style of scientific debate is the contribution. I think it's very useful for people to see how new scientific findings are made and come to be accepted; the idea, for example, that you can attack a fellow's theory without attacking him personally.
Reis: Do you really feel that’s what happens in science?
Sagan: It's at least the ideal. It certainly isn't the ideal in politics. I mean imagine a political debate. Politician A says, "The gold standard is disastrous for the following reasons," which he presents. Politician B, who thought the gold standard essential then replies, "Well, thank you very much, I haven't seen that point of view before. That's a great help to me; you're probably right." Have you ever heard of a political debate in which the opponent was told, "You're probably right; thank you very much?" That happens often in science, perhaps not often enough, but much more often than in other fields.
Reis: Can you tell me something about your current research efforts?
Sagan: My greatest satisfaction is in scientific research. I enjoy the design and execution of space missions enormously. I enjoy the reduction and analysis of data. I enjoy setting up and executing laboratory experiments. I enjoy carrying out calculations. I enjoy finding out how the universe works. I don't nearly as much enjoy administering, public lecturing, although I enjoy that, editing, or a lot of other things I do.
Reis: What are you working on now?
Sagan: We're working on a variety of projects. We're still deeply into the analysis of Mariner 9 Mars data, largely windblown dust and channel anatomy and physiology. We're working on theoretical models of climatic change on Mars, and how much water was required to produce a particular channel. We've done comparisons of climatic change on Mars with climatic change on earth, and we're doing calculations on what happens to the climate of the earth when you inject a large amount of volcanic dust into the atmosphere. For example, can you make ice ages that way? How is dust in the earth's atmosphere connected with dust in the atmosphere of Mars? What does the microwave spectrum of Venus say about the composition and thickness of its clouds? We're studying the atmosphere, clouds, and organic chemistry of Jupiter and the stability structure and time evolution of the atmosphere of Titan. We're doing some work on the origin of planetary systems. We've just acquired a very sensitive gas chromatograph/mass spectrometer with which we intend to do studies of the amino acids and other molecules that are made in our primitive Earth and Jovian planet experiments. We're also deeply into preparations for the Viking-Mars, Mariner-Jupiter-Saturn missions. That's a representative sampling of the kind of research that we're into and enjoy doing.
Reis: Who is “we”?
Sagan: I run a small organization called the Laboratory for Planetary Studies, which is part of the Center for Radiophysics and Space Research at Cornell. There's a handful of planetary astronomers, and maybe 8 or 9 graduate students, mostly in astronomy, but some in physics and geology.
Reis: It all sounds very exciting.
Sagan: It is. ✰
(Originally published in the May / June 1975 issue)
Richard Reis was the Executive Director of the Astronomical Society of the Pacific between 1974 and 1978. He also acted as the Mercury editor in its first few years.
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