Such a large radiation death rate seems outrageous to us now. But then, in the core years of the nuclear-tipped Cold War, an annual casualty rate of 1,000 people was the statistical background. This was an era when the deaths of hundreds of millions from a nuclear exchange could easily be imagined. A level of 1,000 nuclear fallout–related deaths worldwide was absorbed into conventional thinking as were the 50,000 U.S. highway fatalities per year. Many more died from cigarettes.
Nuclear deaths were not exactly taken for granted. Protests eventually led to a ban on open-air nuclear testing. But that would be years later. Orion and its exhaust, set against the then known yearly radioactivity budget, seemed feasible. Still, the likely sting of Orion’s plume, even if statistically it were no more than one person killed per mission, ate away at Dyson’s conscience. The Bomber Command ethos—killing innocent people in the interest of victory—had kicked in. His enthusiasm cooled.35
Von Braun’s rockets were winning the race. They were already scheduled for hurling astronauts into near-Earth orbit. In an effort to address the problem of Orion’s radioactive exhaust, Dyson went to the weapons lab at Livermore, California, where he worked on the problem with Edward Teller. Dyson, in the role of a bomb designer for the one time in his life, struggled for a brilliant, frenzied couple of weeks on trying to devise a nuclear device that minimized the ill effects of bombs exploded in a good cause. He enjoyed working with Teller and with his young colleagues, who all toiled in anonymity. But they ran out of time. The kind of bomb Teller and Dyson were seeking, now called a neutron bomb, wouldn’t be possible for many years.36
Away from Princeton now for months, Dyson had to decide. Should he stay out west with Orion or return east? He enjoyed the Orion camaraderie, especially his friendship with Ted Taylor. He had surprised himself at the depth of his commitment to doing practical research:
The fifteen months I spent on Orion were the most exciting and in many ways the happiest of my scientific life. I particularly enjoyed being immersed in the ethos of engineering, which is very different from the ethos of science. A good scientist is a person with original ideas. A good engineer is a person who makes a design that works with as few original ideas as possible.37
Dyson could tell, however, that the project’s momentum was slipping away. Had the recessional begun? Should he convert his Orion consultant’s position into something permanent at General Atomic or return to the Institute for Advanced Study?
Freeman Dyson, thinking now of a test firing of the rocket, went with Ted Taylor to a remote site in the Nevada desert, a place called Jackass Flats. Here he had another one of those moments when his inner universe got disturbed. Standing there in the middle of nowhere, what impressed him was not so much the natural beauty of the place but the utter silence. The silence was so profound that he referred to it later as “soul shattering.” What he and his fellow Orion-eers were preparing to do was to invade this sound-less, wind-less preserve with the high-decibel screech of powered machinery, the bustle of construction crews, and, finally and grandly, the blast-and-flash takeoff of a nuclear rocket. Dyson was uncomfortably tickled by a sensation he recognized as shame. “The first shadow of doubt about the rightness of Orion came into my mind with that silence.”38
9. Civilized Behavior
Dyson Searches for Extraterrestrial Intelligence
(EARLY 1960s)
Was invasion the right word? The opposing forces met but were oblivious to each other—the Martians too small to be seen by the Earthlings and the Earthlings too slow to be perceived by the Martians. The invaders from Mars consisted of a cloud of microorganisms; they possessed radio telepathy and distributed consciousness but did not otherwise have a solid body. The Earthlings had bodies but had to resort to spoken words or machines to transmit messages among themselves. Insubstantial as they were, the Martians had a sophisticated culture. They had come to Earth looking for resources, especially diamonds. They found diamonds but looked right past the human inhabitants of the planet.
This story about first contact comes from Last and First Men, the 1931 novel by Olaf Stapledon.1 If we encountered an intelligent alien species, would we even recognize it? Maybe not. Stapledon’s books contain much discussion of sociology, the relations between the sexes, and how organisms sense their environment and survive in hostile conditions. The novels have little in the way of plot or complex characters. Some science fiction readers have never heard of Stapledon. Others believe he might be, along with H. G. Wells, the greatest writer in the genre.2 Stanislaw Lem and C. S. Lewis were influenced by him. Arthur C. Clarke, author of 2001: A Space Odyssey, was infatuated by Stapledon’s book; “It transformed my life,” he said.3
You are partly what you read. The things found in books can be absorbed into your thinking, where they resonate for years. Such was the case with Freeman Dyson, who in wartime London stumbled upon Stapledon’s writings. Years later they were to provide Dyson with rich ideas about the diversity of life in the universe, a theme that would be at the heart of his own writing career.
In Stapledon’s 1937 novel, Star Maker, the reader encounters an even wider spectrum of intelligent beings, including the Nautiloids, an ocean-going race of galleon-like creatures with rudders, sails, and hulls. In another story, we meet the Flames, a species living entirely within stars. Stapledon’s 1944 novel Sirius is about a dog with the mental abilities of a man. The creature has a human lover and he struggles to reconcile human and canine worlds. Are such things possible? Can the boundaries among species be transgressed? Can life survive in vacuum or at low temperatures? Can things like stars be alive? Stapledon pondered these topics through fiction, Dyson through science.
Multiple human species do not currently exist (the Neanderthals died out 30,000 years ago), Martian organisms have not come into our midst (as far as we know), and Orion-class ships aren’t yet capable of ferrying astronauts to Mars, much less to the stars. Dyson found this unsatisfactory. He continued to argue for Orion’s approval. But in the meantime, his dreams of interplanetary or interstellar travel would have to take a different form. Reconciling himself to an earthbound existence, he sought other creative outlets for putting his Space Traveler’s Manifesto into practice.
Lebensraum
Dyson’s fifteen months in La Jolla were up. Back on Earth, things had changed a lot. At the beginning of those fifteen months his family had consisted of Verena, Esther, George, and Katarina. Now his family was Imme, Esther, George, and Dorothy, a new daughter born in September 1959, just two weeks before the Dysons were due to leave La Jolla. One branch of the family split off: Katarina remained in California with Verena, who had a job at San Jose State College. (Georg Kreisel returned to a job in Britain.) The main Dyson branch returned to Princeton. Imme was not a mother’s helper anymore. She was the mother.
Dyson was not done with Orion. He went back to San Diego in November 1959 for a test firing of a nonnuclear Orion mock-up. A refrigerator-sized craft, powered by a succession of conventional chemical blasts, was lofted up past a tower. Dyson collected some shards from this experiment and for many years kept them in his desk drawer. In 1960, Project Orion passed over into the custody of the U.S. Air Force.
Instead of immigrating to another star system aboard Orion, Dyson remained on his home planet, safely in his office at the Institute for Advanced Study, and did what scientists have long done—allowed stars to come to them in the form of light waves. For the last few centuries lenses mounted in telescopes helped to gather the feeble light cast by distant suns. Later, photography extended astronomical prospects by performing two important services. First, it fixed the images of the sky in a permanent record on a coated glass plate and later in an electronic array of pixels. Second, it accumulated light for seconds or minutes—something the human retina could not do—greatly strengthening the image. For instance, when you see a picture of the pinwheel-shaped Andromeda galaxy you see an image accumulated over many seconds. A human eye, even using a powerful telescope, w
ould not be able to form such a sharp image.
Additional technology allowed astronomers to see the universe in a new way using light that was previously invisible. The frequency of this light was not matched to our eyes, which are sensitive only to a small portion of a wide spectrum of electromagnetic radiation. Practice with radio and television broadcasts and wartime development of radar meant we could “look” at the sky at those frequencies. It’s as if we could suddenly perceive new colors. Then still more colors became available; after the first rockets could loft objects into orbit above the absorbent blanket of our atmosphere, astronomers could image the heavens at very high frequencies, encompassing the ultraviolet and X ray portions of the spectrum.
Through these new windows scientists uncovered unexpected phenomena, such as X-rays from the sun, showing that the temperature of the solar corona was far higher than that of the sun’s surface. Radio waves from Jupiter suggested the presence of a powerful magnetic field welling up from inside the planet. Could the new light provide signs of living things at remote planets or stars? Better still, could we discern hints of an intelligent civilization in the form of radio broadcasts?
In a pioneering 1959 paper two Cornell physicists, Philip Morrison and Giuseppe Cocconi, calculated optimal radio frequencies for locating distant civilizations.4 Another Cornell scientist, Frank Drake, was just then preparing antennas in order to search for exactly such signals. Listening in to the universe with radio waves became the primary approach to the search for extraterrestrial intelligence, an endeavor called SETI for short.
Dyson took a contrarian view. He believed that the radio method of searching the sky would result in a frustrating game of hide-and-seek. First, he said, the hypothetical aliens might not be talkative. They might be shy or devious and want to hide their existence rather than proclaim it. Second, whether or not they were in a talkative mood they would not be able to hide their heat. All physical objects at temperatures above absolute zero emit heat waves. Especially in our world, typified by a temperature of about 300 degrees kelvin, what we commonly refer to as room temperature, things cast off a lot of waste heat in the form of infrared radiation. As with radio waves and X-rays, infrared (IR) waves can be detected.
IR sensors show, for example, where heat is leaking out of a home on a cold winter’s night (usually around un-insulated windows and doors) or show where heat is suffusing from a human body just after vigorous exercise (around the heart, muscles, and any place where warm blood copiously flows). The same principle applies to cities and whole civilizations. They all leak heat on a large scale. Dyson was inspired to thinking about how intelligent bustle could be apparent to outsiders by looking at early satellite pictures showing nocturnal evidence of human activity: oil flares, city lights, and forest-clearing fires.5 What this suggested to him was that while we might not directly observe hints of intelligence, such as episodes of I Love Lucy, we would probably see the warmth of technology at work.
Dyson explored extrasolar civilizations with thought experiments. He tinkered with the outer limits of what was physically possible and squeezed a lot of ideas into a one-page article in Science. Before addressing hypothetical evidence for alien heat, Dyson first assessed the technological civilization we have ourselves already produced in the past few thousand years and how much more complex it could become if we kept going for thousands of years more. Barring catastrophic wars or epidemics, he figured, we could build a society larger and more technically advanced by a huge factor. Assuming a modest growth of 1 percent per year in the population and in industrial complexity, society would enlarge by a factor of one billion after only 3,000 years.6 A civilization that large would have outgrown its home planet.
In his paper Dyson therefore had reason to refer to a Malthusian scramble for the material means of survival. He referred to the need for more living space, or Lebensraum—the German term associated with Adolf Hitler’s territorial aspirations in Eastern Europe—when characterizing the expansion of society over eons. To reach an advanced state, Dyson argued, a civilization would need to command amounts of energy and material far above current earthly levels. Right now the Earth’s surface intercepts only a tiny amount of the energy the sun sends into space. And of that amount only a tiny fraction is exploited by living things, mostly in the form of photosynthesis.
For human culture to go on expanding it would need much more of the precious solar radiation, eventually all of it. Moreover, available habitable real estate would have to keep pace, far outrunning the portion of the planet’s surface that we currently occupy. As for raw materials, the minerals and metal of all our planet’s mountains would not be enough to equip a future billion-fold-larger population.
The demographic struggles of future societies are an important part of the books of Olaf Stapledon. And so are the solutions to those struggles. In addressing the Lebensraum issue, Dyson specifically borrowed from Stapledon’s novel Star Maker in suggesting that an advanced society, whether for Earthlings or for hypothetical aliens, could procure the extra energy it needed by disassembling an asteroid or even a planet.7 With this scrounged material you could fashion a large array of light-harvesting panels surrounding the star. These panels would serve as both solar energy absorbers and as additional homes for people, the off-Earth continuation of suburbanization.8
What would this array look like? In his thought experiment, Dyson suggested that an advanced society could build a fleet of platforms only a few meters thick or even less, all orbiting the sun at the same distance as Earth. In practice this archipelago would not entirely surround the sun. Owing to mechanical instabilities, the array could not rotate or orbit the sun as a single rigid ball. Nevertheless, this hypothetical energy collector scheme has come to be known as a “Dyson sphere.” Viewed from afar, these arrays, drinking in solar energy and then glowing at a wavelength of 10 microns, would be the tip-off that something intelligent was happening in space in that region.9
While writing up his article for Science, Dyson became afraid that some people might consider it undignified for a professor at the Institute for Advanced Study to be making conjectures like this. So as a courtesy he sheepishly sought Oppenheimer’s permission to venture onto such speculation.10 Oppie gave his consent, and the paper was published. Dyson never again felt inhibited from letting his imagination roam widely.
The leviathan space habitat construction Dyson had in mind is obviously beyond our current technical means. Mustering a Jupiter-sized load of building materials would make even Project Orion look puny. Dyson course recognized the magnitude and impracticality of his plan. His self-appointed task was not to say what will happen but what could happen. Furthermore, he wasn’t even necessarily talking about what future Earthlings could do but about what might have happened already in some far-away planetary culture.
How common are such societies? Frank Drake devised a formula for computing the likelihood of intelligent life existing in our galaxy. The probability for this would be roughly proportional to a number of factors, such as the fraction of stars with planets, the fraction of planets supporting living things, and the fraction of intelligent societies that possess the means of interstellar communication.
VIKING TECHNOLOGY
Dyson did not trust such formulas. It’s hard enough to predict the advent of life and intelligence on our own planet. The chemical circumstances surrounding the appearance of primitive living cells are so murky as to preclude saying anything meaningful about how things are alive on remote planets, much less saying anything about flourishing civilizations.11 Perhaps we should look at the hallmarks of civilization here on Earth.
“What is civilisation?” asked Kenneth Clark. “I don’t know. I can’t define it in abstract terms—yet. But I think I can recognize it when I see it; and I am looking at it now.” Clark, an art historian, opened his 1968 television series Civilisation with a cinematic view of the Pont des Arts in Paris, a pedestrian bridge across the Seine linking the Louvre museum and the Institu
t du France, two great fixtures in the cultural life of the French nation. Visible in other directions are Notre Dame cathedral, quaint bookstalls along the river embankment, charming bistros, art studios, government ministries, and still more museums, all constructed in a variety of architectural styles over centuries. Is this the most civilized place on Earth? Clark was too polite to say so exactly.12
What is the most civilized place in the galaxy? There is no answer to this absurd question. For Dyson, in his Science article, civilization is defined, or at least revealed, by high technology. For Clark it usually means high art. Dyson asks to see solar energy collection, while Clark asks to see Rembrandts. Actually Clark lists things like art and good manners as being but the outward signs of civilization. The actual causes of civilization have more to do with outlook. This Clark illustrates with a shot of the 2,000-year-old Roman aqueduct, the Pont du Gard, in southern France:
Of course civilisation requires a modicum of material prosperity—enough to provide a little leisure. But, far more, it requires confidence—confidence in the society in which one lives, belief in its philosophy, belief in its laws, and confidence in one’s own mental powers. The way in which the stones of the Pont du Gard are laid is not only a triumph of technical skill, but shows a vigorous belief in law and discipline. Vigour, energy, vitality: all the great civilizations—or civilizing epochs—have had a weight of energy behind them.13
As Clark reminds us, civilization doesn’t need to be kind. The Vikings, who in the eighth century had terrorized the earlier inhabitants of the place that is now Paris, were very cruel and yet capable of producing art objects of great beauty.
Maverick Genius Page 17