by Carl Sagan
What about Rayleigh scattering on Venus? Because the atmosphere is so much denser, Rayleigh scattering there is much more important. Were we to strip the clouds off Venus, we would still be unable to see its surface from above. Visible light of all colors would be scattered so many times in the Venus atmosphere that no image of any surface details would be discerned. In the near infrared, at wavelengths longer than the human eye is sensitive to, the surface could, however, be seen from above. But there are clouds. Radio waves penetrate the clouds and the atmosphere of Venus and the first radar maps of Venus are being developed (see page 80). In a few years, Cornell University’s great Arecibo telescope in Puerto Rico will begin mapping the surface of Venus by radar with higher precision than the best ground-based optical maps of the Moon. Already, there are hints of mountain ranges and great impact basins on the surface of this enigmatic planet.
At the surface of Venus, Rayleigh scattering is also an extremely important effect. Just as we cannot see the surface in visible light from above Venus, we cannot see the sun in visible light from the surface of Venus–even if there were a break in the clouds. If there were intelligent life on Venus, astronomy would be very slow to develop; and radio astronomy would emerge first. The Venera 8 spacecraft found that sunlight does reach the surface of Venus during the day, but it is so attenuated by passage through the clouds and atmosphere that, even at midday, it is no brighter on Venus than at twilight on the Earth. The sunlight would be a hazy and diffuse patch of deep ruby-red light, whose rising and setting could only indistinctly be determined.
If you were standing in some protective suit on the surface of Venus and put on violet sunglasses, you would see no farther than a few dozen feet. The Rayleigh scattering in blue light is so strong on Venus that the visibility in the violet is small. But because long wavelength light is scattered less than blue, at the extreme red end of the visible spectrum–with red sunglasses on–you could see perhaps a thousand feet. At the surface of Venus everything would be suffused in a deep red gloom. We would have a perception of color, but only for objects very close to us. Our surroundings would be an indistinct roseate blur.
Venus thus seems to be a place quite different from the Earth, and alarmingly unappealing: Broiling temperatures, crushing pressures, noxious and corrosive gases, sulfurous smells, and a landscape immersed in a ruddy gloom.
Curiously enough, there is a place astonishingly like this in the superstition, folklore and legends of men. We call it Hell. In the older belief–that of the Greeks, for example–it was the place where all human souls journeyed after death. In Christian times it has been thought of as the post-mortem destination only of one of two categories of moral persuasion. But there is little doubt that the average person’s view of Hell–sizzling, choking, sulfurous, and red–is a dead ringer for the surface of Venus.
Although terrestrial biological molecules would fall to pieces rapidly on Venus, there are organic molecules–for example, some with a complex ring structure–that would be quite stable under the conditions of Venus. It is difficult to exclude life there, but we can certainly say it would be quite different from what we are familiar with. Any organism that lives there would be wise to have leathery skin. Because of the high atmospheric pressures, it would even make sense to have little stubby wings, which could carry their possessors about without exceptionally strenuous flapping. A devil is a very good model–except for his mannish and goaty aspects–for an inhabitant of Venus. Milton and Isaiah called Lucifer “Son of the Morning,” the morning star. For thousands of years Venus and Hell have been identified.
This is all a very curious coincidence, but I cannot bring myself to think that it is anything more than that. The chief point is that in all the legends one gets to Hell by going down, not up. The classical world of Greece and Rome and the ancient Near East were peppered with active volcanoes. Such volcanic terrains, like in contemporary Iceland and Hawaii, are bleak, desolate, and eerily beautiful landscapes. Sulfurous gases emanate from volcanic vents; lava fountains and flows suffuse the surroundings in red. It is very hot: You singe your eyebrows if you get too close to the lava in a collapsed lava tube. And all this heat, redness, and smell come from down below. It was not very difficult for our ancestors to imagine that volcanic terrains were apertures to a quite different igneous world called Hell.
The inside of the Earth and the outside of Venus are alike but not identical. They are both unpleasant for humans. But they are both of extreme scientific interest–worth at least an extended visitation, if not a homesteading. Dante knew about that.
14. Science and “Intelligence”
I spent my first two postdoctoral years at the University of California, Berkeley, where, among other things, I was concerned with searching for life elsewhere and with the sterilization of space vehicles intended for places like Mars–we wished not to contaminate the Martian environment with microbes from Earth.
One bright spring day I received a phone call from an Air Force general whom I had met at several scientific meetings. He had been working chiefly on aviation medicine; I will call him here Bart Doppelganger. General Doppelganger informed me that he was in Los Angeles with three Soviet scientists, one of whom was in charge of the Soviet effort for constructing instruments to search for extraterrestrial life. His name was Alexander Alexandrovitch Imshenetsky (there is no reason to change his name; unlike some others in this narrative he has nothing to be ashamed of). It was Imshenetsky’s first visit to the United States. Yes, I would certainly be interested in meeting him. When? The answer was “immediately.” So I drove to San Francisco airport, flew to Los Angeles, and took a taxi to an address given to me by our General Doppelganger.
It was the home of a professionally well-known UCLA brain physiologist. In the living room, upon my arrival, were the physiologist, other aviation medicine experts from UCLA, General Doppelganger, three Soviet scientists (two in aviation medicine and Academician Imshenetsky), and a translator. I will call the translator Igor Rogovin; he was an American employee of the Library of Congress assigned to do translation for the three Russians on their visit to the United States. The only thing that struck me as somewhat peculiar was that the English of all three Russians was quite good. So why a translator?
Everyone was jolly, pleasantries were exchanged, drinks made the rounds–and Igor Rogovin also made the rounds. There was no conversation from which he was absent for more than a few minutes. He was very busy, like a manic bee obsessively flitting from flower to flower.
After a while, the plan was for all of us to drive to Los Angeles International Airport, where the Russians were later to catch a plane. Before their flight, we were all to have dinner. There were more of us than could fit into one car, and Rogovin could not easily ride in both cars at once. Imshenetsky, some others, and I rode in one car, and Rogovin and the others in a second. During the twenty- or thirty-minute drive, Imshenetsky and I had a fruitful exchange of views on methods of life detection and space-vehicle sterilization technology. It was the first such contact I had had with a Soviet scientist.
We arrived at the airport, bags were checked, and the Soviets excused themselves to go to the men’s room. Waiting outside, I found myself alone with Igor Rogovin–who immediately said to me out of the corner of his mouth, and in a style of vocalization that went out with James Cagney and Humphrey Bogart, “Hey, kid, what’d ya find out?”
Being unwise in the ways of the world, and pleased with the information Imshenetsky and I had exchanged, I rapidly summarized what I had learned.
“Pretty good, kid. Who do you work for?”
“The University of California at Berkeley,” I replied brightly.
“No, no, kid, not the cover.”
Igor Rogovin’s occupation, if not his identity, gradually dawned on me. With a rising fury I explained to him that it was possible to have a conversation with a Soviet scientist that was intended for the benefit of science rather than for the benefit of American military intelligence
services. Before Rogovin could reply, our friendly Soviet guests re-emerged, and we all went off to dinner.
Although seated again next to Imshenetsky, I found myself unable to talk to him on any subject remotely approaching science. As I recall, our primary topics of conversation were American films and Soviet poets. After a number of drinks, Alexander Alexandrovitch Imshenetsky offered the opinions that William Shakespeare was the leading Russian poet and American cowboy films were excessively violent. Several hours easily could be spent discussing these two propositions. As the Russians left to fly home, I returned to Berkeley.
The next morning, I turned to the white pages of the San Francisco telephone directory and, under “United States Government,” found a section marked “Central Intelligence Agency.” On dialing the number indicated I encountered a cheerful voice that said something like “Yukon 4-2143.”
“Hello, Central Intelligence Agency?” I said.
“What can we do for you, sir?”
“I have a complaint to file.”
“One moment, sir, I will give you our Complaint Department.” This was shortly after the Bay of Pigs, and I guess they had been getting a lot of complaints.
Upon reaching–yes–the Complaint Department, I rapidly launched into a synopsis of my encounter with Mr. Rogovin, but was quickly silenced with an injunction that this was not the sort of thing one talked about over the telephone. I suppose his phone was tapped. We made an appointment for later that afternoon in my office.
Sure enough, at the prescribed time, two neatly dressed business-suited young men arrived, bearing plastic identification cards with the signature of John McCone, who had recently been appointed Director of the Central Intelligence Agency. After expressing my general annoyance by an exceptionally long scrutiny of their IDs, I launched into my story. In their faces was mounting concern. At the conclusion of my narrative, they explained to me that Rogovin’s behavior was very unlikely to be the behavior of any employee of “the agency.” They were very concerned about such a story, particularly after the “bad press” they had been getting about the Bay of Pigs. They would do everything to track the story down if I would not embarrass the agency by further disseminating the story. I agreed to keep quiet, for a while, and they departed.
About a week later I received a phone call: “Dr. Sagan, this is Mr. Smith, who was in your office last week. You recall the matter about which we talked?” I gathered that his phone was still tapped.
“We have been able to establish that the party in question–you know who I mean?–does not work for our organization under that name. We are, of course, pursuing other names and will get back to you as soon as we can.”
It had taken them a week to scrutinize the personnel roster of the Central Intelligence Agency. The roster must either be very long or very secret.
Several days later, in similarly veiled language, I was called and told–in a voice that seemed to express considerable concern–that Igor Rogovin did not work for the CIA under any name whatever, and that they were, under the circumstances, naturally curious to know for whom he did work.
After another week had passed, the CIA made an appointment to speak with me once again in my office. The same two gentlemen arrived, again bearing the same two plastic cards signed by John McCone. They informed me that, after exhaustive investigations, they had discovered that Igor Rogovin, while nominally working for the Library of Congress, was, in fact, an employee of Air Force Intelligence. They again assured me that no representative of their agency would ever behave in so uncouth a manner, and departed. What stood out most clearly was that it had taken about two weeks for the Central Intelligence Agency to determine the employment of a member of a fellow U.S. intelligence organization.
This story has a coda. A year or two later the international space organization, COSPAR, was meeting in Florence, Italy. In one of the splendid side benefits of such meetings, the Uffizi Gallery was opened one evening especially for the members of the COSPAR delegations from various nations. As chance would have it, I was with Alexander Alexandrovitch Imshenetsky as we entered an enormous and apparently empty Botticelli-inundated gallery. And there, at the other end of the gallery, a human figure could dimly be perceived. I felt Imshenetsky stiffen. Peering intently, I could now make out the visage of Igor Rogovin, his face disguised by a beard. He was, no doubt, traveling incognito. Imshenetsky leaned over to me and whispered, “Isn’t that the fellow who was with us in Los Angeles?” When I nodded assent, Imshenetsky murmured, “Very stupid fellow.”
That Rogovin was working for Air Force Intelligence is, in retrospect, not so surprising, since I had been invited to Los Angeles by General Doppelganger. That Soviet plans for the search for life elsewhere or for the sterilization of spacecraft could be considered of interest to Air Force Intelligence is perhaps more surprising. That American intelligence agencies would attempt to use comparatively innocent young scientists (I was twenty-seven and politically unsophisticated) to carry out such a purpose is appalling. At least it appalls me.
There are many other such stories involving both American and Soviet intelligence organizations. The general effect of such incidents is to detract from the credibility of legitimate scientific exchanges among scientists of different countries. Such exchanges are particularly necessary in an age that hangs a thread away from nuclear destruction, and in which scientists have access to at least half an ear of the politicians in power. The fact that such intelligence activities are practiced in an entirely regular and invariable manner on the Soviet side does not, in my view, weaken this argument. The intrusion of “intelligence” into international scientific exchanges of this sort is, whatever else it is, just not intelligent.
15. The Moons of Barsoom
In my boyhood I was lucky enough to come upon a set of turgidly written novels with names like Thuvia, Maid of Mars, The Chessman of Mars, The Princess of Mars, The Warlords of Mars, and so on. They were, needless to say, about Mars. But they were not about our Mars–the Mars revealed by Mariner 9.
At least I don’t think our Mars is like the Mars of these novels by Edgar Rice Burroughs, the inventor of Tarzan. His Mars was Percival Lowell’s Mars–a planet of ancient sea bottoms, working canals and pumping stations, six-legged beasts of burden, and men (some headless) of all colors, including green. They had names like Tars Tarkas. Possibly the most remarkable hypothesis proposed by Burroughs in these novels was that human beings and inhabitants of Mars could produce live offspring–a biologically impossible proposition if the Martians and we are imagined as having separate biological origins. Burroughs wrote decorously of the interfertility of a Virginian miraculously transported to Mars and Dejah Thoris, the princess of a kingdom with the improbable name of Helium. I have little doubt that the precedent of a kingdom called Helium led directly to the planet called Krypton, home of the comic-book hero Superman. There is here a rich vein of untapped literary ore. The future may hold planets, stars, or even entire galaxies named Neon, Argon, Xenon, and Radon–the remaining noble gases.
But the name invented by Burroughs that has haunted me across the years is the name he imagined the Martians gave to Mars: Barsoom. And it was one phrase of his more than any other that captured my imagination: “The hurtling moons of Barsoom.”
For Mars is indeed a world with two moons–a situation that would appear to the inhabitants of Mars as entirely natural as our one Moon does to us. We know how our solitary satellite looks to the naked eye from the surface of Earth. But what do the moons of Barsoom look like from the surface of Mars? This question, which intermittently plagued my boyhood, was not to be answered until 1971 and Mariner 9.
The moons of Mars were invented by Johannes Kepler, the discoverer of the laws of planetary motion and no intellectual lightweight. But he lived in the sixteenth century, in a different intellectual climate from the present. He cast horoscopes for a living; astronomy was his passion more than his occupation. His mother was tried as a witch. When Kepler learned of Gali
leo’s discovery, with one of the first astronomical telescopes, of the four large moons of Jupiter, he immediately concluded that Mars had two moons. Why? Because Mars was at an intermediate distance from the Sun, between Earth and Jupiter. It must obviously have an intermediate number of moons. The observations seemed to show Venus with no moons, Earth with one, and Jupiter with four (the actual number, we now know, is twelve). Kepler could have deduced either two or three moons for Mars. But bearing a lifelong passion for geometrical progressions, he chose two. The argument is, of course, fallacious. Saturn’s ten moons, Uranus’ five, and Neptune’s two in no way fit his scheme, which is not scientific but aesthetic.
But Kepler’s prestige was immense, particularly after Kepler’s laws of planetary motion were derived from gravitational theory by Isaac Newton; and so, literary allusions to the two moons of Mars fluttered down the centuries. In Voltaire’s longish short story “Micromegas” a denizen of the star Sirius notes casually, while touring our Solar System, that Mars had two moons. There is a more famous reference to two Martian moons in Jonathan Swift’s satire of 1726, Gulliver’s Travels–not the part about the very small people, or the part about the very large people, or the part about the intelligent horses, but a less widely read part–the part about the floating aerial island of Laputa. The episode is undoubtedly a tightly reasoned critique of English-Spanish relations in Swift’s time, because la puta is Spanish for prostitute. The political metaphors are obscure, at least to me. At any rate, Swift announces casually that astronomers on Laputa have discovered two swiftly moving moons of Mars, and have provided information on their distances from Mars and their periods of revolution about Mars–information that is incorrect, but that is not a bad guess. There is an entire genre of writing on how it was that Swift knew about the moons of Mars, including the suggestion that he was a Martian. Internal evidence suggests that Swift was no Martian, and the two moons can almost certainly be traced directly back to Kepler’s speculations.