Beyond that, what? Well, then it’s off to other stars and across the galaxy with transportation technology that hasn’t been invented yet. More unfathomable than the rocket design is the social fabric that could hold together a community on treks far more arduous than those of the biblical Israelites across Sinai or Paleo-Siberians over the Bering land bridge.
But intelligence, viewed over a wide enough breadth, is patient. “Mind has waited for 3 billion years on this planet before composing its first string quartet,” says Dyson. “It may have to wait for another 3 billion years before it spreads all over the galaxy.”22
PERSISTENCE
The third part of Dyson’s grand message—the bit about this being the most interesting of universes—concerns the relation between life and the cosmos. Dyson chafes at jurisdictional boundaries, such as the one that separates cosmology from biology. He finds it a pity that the overall theory of biology, consisting of Darwin’s evolution by natural selection plus modern genetics, and the overall theory of cosmology, consisting of the big bang model supplemented with quantum mechanics and general relativity, have progressed in past decades pretty much without reference to each other.
The only life we know about, here on Earth, came along about 4 billion years ago, some 10 billion years after the big bang moment. So it’s hard to say what connection there is between the origin of life and the origins of the visible universe itself. These are difficult questions for scientists to grapple with. Indeed they have not always been viewed as scientific issues at all, but something more appropriate for theologians.
Late Life
If the respectability of the study of cosmic origins was established by the publication of Steven Weinberg’s The First Three Minutes in 1977, how about the last three minutes? How about the study of the remote future of the cosmos? Not yet a legitimate scientific enterprise, the indefinite future had long been in the hands of theologians and novelists like Olaf Stapledon. Dyson sniffed an opportunity.23
In 1978 he gave the Arthur Lectures at New York University on the topic “Time and Its Mysteries.” His particular twist on this assignment was to speak about time and biology. Not the biology of the past 4 billion years, nor the biology of our current human cultural era, not even the future out to the comet-dwelling era of Dyson trees. Instead he talked about life a billion trillion trillion years from now.
Dyson doesn’t pretend to predict what will happen. He is a great extrapolator. He paints the future. His palette consists of thermodynamic lore, phase transitions, the trajectories of celestial objects, and the decay of nuclei. The portrait he draws of the geriatric universe is more diaphanous than the emptiest landscapes of Monet or Turner.
What does physics say about the far future? First, there will be inevitably a series of deaths. Our own sun, having exhausted much of its internal nuclear fuel over the next few billion years, will actually expand for a while, enveloping and burning Earth. Later still the sun will shrink to the status of a white dwarf star. Given enough time, and in Dyson’s Arthur Lectures there was lots of time, many slow or rare processes come to pass. To express so colossal a chronology we must use exponential notation. In this convention a million—1,000,000, a one followed by six zeros—is written as 106. A trillion—1,000,000,000,000—is written as 1012. The strung-out phenomena of the universe include, in Dyson’s estimation, the detachment of planets from stars (1015 years from now), the detachment of stars from galaxies (1019 years), and the growth and then evaporation of black holes into a thin gas of particles and radiation (1064 years).24
The big biology-cosmology questions are: Can life persist into these extreme times? And if life survives will consciousness still be active? Will intelligible communications continue even as the universe expands, making it harder and harder to harvest matter and energy? Early life, typified by the pilgrimage away from ocean vents, may have found temperatures to be a bit warm. Current life, at least for human habitation on Earth, finds temperatures just about right. Future life, in whatever form it takes, will find the thermostat turned way down.
String Quartets
To Dyson’s surprise, his NYU host submitted the lecture notes to the prestigious journal Review of Modern Physics.25 To his greater surprise, the editors accepted the piece.26 It became for many years the main scientific description of the physics of Deep Time.
Dyson is an optimist. He finds that eternal life and finite energy are compatible providing that certain modifications to life come about. First some bad news: life and intelligence tied inextricably to ordinary matter, such as the biomolecules that compose our bodies and brains—requiring warmth and liquid water to function well—will not endure. Life will have to take a radically different form. Even the Martian invaders imagined by Stapledon as a cloud of tiny organisms are too matter-bound. Life has to be simpler, maybe no more than waves passing through a mist of micron-sized dust grains. It’s hard to imagine how such a pulse could be alive, much less carry on communications. But then, as Dyson points out, we wouldn’t have predicted the architecture of a bacterium if we didn’t already know it.27
The scope of late life Dyson provides in his landmark Review of Modern Physics article far transcends his previous ponderings over the riddle of existence. Forget nuclear test bans and Project Orion and homesteading the Kuiper Belt. Forget even the advanced degree of civilization needed to construct Dyson spheres that intercept and use the entire energy emission of a star. At this point in the far future, the existence of life itself, anywhere and everywhere, is at stake. The kind of life forms embodied in dust clouds (a “Dyson swarm” as we might call it) is far more advanced. It would have to be if it were frantically going to scrounge energy in an expanding and cooling universe.
Dyson does the math. He sets out formulas for calculating the energy consumed and later dissipated by the swarm society. This minimum energy is proportional to the square of the creature’s temperature and to its “complexity.” Complexity, essentially the same as consciousness, is related to “the amount of information that must be processed in order to keep the creature alive long enough to say ‘cogito, ergo sum.’”28
Dyson calculates that the complexity value for a human being to produce one second’s worth of consciousness is 1023 bits of information. For the entire human race, one second of consciousness is encapsulated in the form of 1033 bits. The bigger the consciousness, the bigger the energy requirement. To keep ahead of the inexorable expansion of space-time and the dilution of energy resources, the swarm would have to reduce its temperature or reduce its level of consciousness. But even this, he sadly concludes, won’t be enough for life to endure indefinitely.29
Hibernation
Wait. Dyson comes up with an alternative. The creature can hibernate. It can slow its thinking process to a halt and wake up later. In this way, taking ever longer naps, it can conserve energy.
But what about the quality of life? We’re no longer talking about owning a fine home, dining well, and reading a good book. However, it wouldn’t be much fun if, as the eons crept past, the creature would have to surrender its mental faculties in an effort to economize on memory space. After all, the third part of Dyson’s grand manifesto, the third part of the message he has come to preach, is that the universe is interesting in a meaningful way (a sentiment to be explored in the next chapter) and that the presence of humans, or at least some strain of intelligent creatures, should be around to help make things interesting.
Analog vs. Digital
For a full life, Dyson says, you should have a growing memory, one that can accommodate new experience while retaining the old. This can be performed if the creature forswears digital memory—the form of data storage used in most present computers, in which information is represented by strings of 0s and 1s—in favor of analog memory. Dyson provides an example of what this means: information can be associated with, say, the apparent angle between two distant stars.30 With this understood, intelligent life might hang on.
Dyson maintaine
d this view of persistent life for many years. Then in the late 1990s, new observations changed the picture. For decades the majority opinion among cosmologists was that the expansion of the universe could follow one of two courses: either the expansion would continue at an ever slower rate (owing to the mutual gravitational tug of galaxies upon each other) or would even reverse, causing the galaxies to come back into closer proximity, eventually bringing about a grand crunch, a big bang in reverse.
Well, new telescope measurements seemed to upend this view. Neither scenario was cogent anymore. Measurements of remote supernovas now suggested that the rate of expansion is not slowing, not reversing, but growing. The big bang is accelerating. The overall thinning of energy resources is actually speeding up. The universe as a place to live is becoming impoverished at a much greater rate than we had earlier thought.
Lawrence Krauss, a physicist at Arizona State University, deduces that space is expanding so rapidly that galaxies will eventually accelerate away from our view. They will vanish from sight. Krauss calls this the “worst of all possible universes.” He and Glenn Starkman, a physicist at Case Western Reserve University, determine that we don’t even have to wait all that long for the thinning of the universe to be dire: “Within two trillion years, well before the last stars in the universe die, all objects outside our own cluster of galaxies will no longer be observable or accessible. There will be no new worlds to conquer, literally. We will truly be alone in the universe.”31
Dyson’s optimism about the eternal persistence of life would seem to be trumped by the emptying of space. Even with ever longer periods of hibernation, there wouldn’t be enough energy, much less coffee, to wake up to. Intelligent creatures would have trouble finding food, much less having meaningful conversations.
Edward Witten, Dyson’s colleague at the Institute for Advanced Study, doesn’t like the idea of an accelerating universe: “It’s definitely the strangest experimental finding since I’ve been in physics,” Witten has said. And yet the facts are the facts, until overwritten by later observations. “People find it difficult to accept,” said Witten. “I’ve stopped expecting the finding to be proved wrong, but it’s an extremely uncomfortable finding.”32
Krauss and Starkman identify themselves as “frustrated optimists.” They suspect that memory and consciousness will probably turn out to be digital and not analog, and under the current understanding of the accelerating expansion of the universe, life cannot persist indefinitely.33
Meanwhile Dyson does not give up. Astronomers have changed their mind about the general mechanism of the universe many times before, he says. Some new mechanism might still turn up—wormholes through space-time—that allow resources to be found for the continuation of life.34
Dyson is irrepressibly the optimist or (as some suspect) the wishful thinker. He regards himself as a scientific humanist in the tradition of H. G. Wells. As a young boy at school, Dyson took refuge in a library where he read Wells’s adventure stories. As an elderly man, Dyson takes refuge in Wells’s expansive view of the human presence in the cosmos. Dyson singles out the opening lines of Wells’s Outline of History: “Not only is Space from the point of view of life and humanity empty, but Time is empty also. Life is like a little glow, scarcely kindled yet, in these void immensities.” For Dyson’s purposes, it is necessary to view the arc of life as being open-ended: “It was important for Wells, and for me, that the stage is large and humanity small. An awareness of our smallness may help to redeem us from the arrogance which is the besetting sin of scientists.”35
16. God and Man at Princeton
Dyson as Preacher
(1985–2000)
AROUND THE DYSON SPHERE
When Freeman Dyson reached his canonical three-score-and-ten, the retirement age for professors at the Institute for Advance Study, his friends and colleagues held a festival in his honor, they had no shortage of topics to cover. This grand event, called “Around the Dyson Sphere,” took place over two days, April 8–9, 1994. The two organizers were professors at the Institute, Frank Wilczek, later to win a Nobel Prize, and Edward Witten, the chief proponent of string theory and a winner of the Fields Medal, the most prestigious award in mathematics.
The program of talks, tied to phases in Dyson’s career, spanned a variety of science and technology subjects: quantum field theory, gravity, missile defense, stability of matter, adaptive optics and telescopes, magnets, the imaging of biomolecules, evolution, pure mathematics, arms control, and the formulation of federal science policy. Dyson was on hand for these talks and good-naturedly commented as the speakers progressed.
The daytime talks were technical in nature, but the after-dinner remarks were convivial, and anecdotes flowed. For example, physicist and New Yorker writer Jeremy Bernstein, who in the mid-1950s had been a short-term visitor to the Institute, recalled seeing Dyson reading the Bible in Russian and (while both of them were working on the Orion project) Dyson being arrested one day when the guards mistook him for an intruder; Dyson had broken his eyeglasses and was wearing snorkeling goggles while walking around in the bright sunshine.
Abraham Pais, like Dyson a theoretical physicist and young professor at the Institute in the 1950s, commended Dyson for helping to make clear many difficult physics concepts, complimented him for being a contrarian, and congratulated him for having found the right mate in Imme Jung. Former Institute director Marvin Goldberger, a member of Jason and a theoretical physicist, asserted (in a letter read out at the dinner) that Dyson had not had many physics collaborators over the years because “he thinks faster than others.” “He might be wrong,” said Goldberger of Dyson, “but never boring.” Marvin Goldberger’s wife, Mildred, who had met Dyson many times at Princeton and at summertime Jason meetings, said that Dyson was always respectful of women. He talked to them at parties with interest, she said. He didn’t need to drop the names of important friends. He didn’t need to be one-up on other people.
Dyson’s daughter Esther was one of the last to speak. She had the impression, growing up, that for all of his accomplishments the thing Freeman Dyson was most proud about was his children. “And now his grandchildren,” she added. “He is optimistic but clear-eyed. I’ve never met anyone more tolerant or understanding.” At the end of the evening, the guest of honor thanked his friends at the Institute (“Where they have been pampering me for forty years”) and at Jason. He was glad to have been a part of both the worlds of science and action.
Freeman thanked Esther for introducing him into still another world, the world of business. And as for his amazing variety of interests, this he attributed to his short attention span. He could never stay focused on one topic for very long before moving on to another.1
Further honors were heaped upon Freeman Dyson. He received the Matteucci Medal (1989) of the Italian National Academy of Sciences; the Antonio Feltrinelli Prize (1990), given by the Accademia dei Lincei; the Oersted Medal (1991), the highest award of the American Association of Physics Teachers; the Lewis Thomas Prize (1996), given by the Rockefeller University for literary efforts by a scientist; and the Burton Award (1999), given by the American Physical Society for work accentuating the role of physics in society. Honorary degrees from colleges kept arriving: Rider College (1989), Bates (1991), Haverford (1991), Dartmouth (1995), ETH Zurich (1995), Scuola Normale Superiore Pisa (1996), University of Puget Sound (1997), Oxford (1997), and Clarkson (1998).
Dyson had done well at the Institute. Privately he wondered if he hadn’t been in a rut by staying in Princeton for so long.2 Getting out into the bustle of a university might have been good for him. He felt, however, that his children wouldn’t have wanted the change. Imme Jung isn’t sure about this view. She and her children speculate that it was Freeman himself who wanted to stay. “He’s married to the Institute,” Imme said. “He’ll never leave.”3
He had been at the Institute as professor for forty years, and was going to continue working there under the designation of professor emeritus, k
eeping his office, with its splendid view of a sprawling grassy space and an immense oak. His office was room number 292 in a building that now bears the name of the mayor of New York—Bloomberg Hall—a generous donor to the Institute. The office across the hall was occupied by Ed Witten. By craning your neck out at the window of Dyson’s room you could see Einstein’s office (now occupied by another professor) in Fuld Hall. The other faculty for the School of Natural Sciences at the Institute at this time were Stephen Adler, Piet Hut, and John Bahcall. Dyson was friendly with his colleagues but generally worked alone.
Although his main work at this point in the mid-1990s was writing book reviews and giving public lectures, he was still interested in mathematical physics. He was then assembling a volume of his select scientific papers, which would be published in 1996. Alongside the papers, Dyson provided a running annotation year by year of his research interests and a generous inclusion of biographical material. He had also, a few years before, published a collection of works (mostly a scrapbook of lecture transcripts and book reviews) from across sixty years. This book, From Eros to Gaia, led off with his schoolboy fantasy from 1933, “Sir Phillip Roberts’s Erolunar Collision.”
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