Pre-Copernican astronomy put the Earth in the center of the world; Copernicus deposed it from its privileged position when he discovered that ours is but one of many planets orbiting the Sun. Over the centuries, advances in astronomy strengthened the Copernican hypothesis, showing that not only was Earth not the central body in the solar system but that the system itself was located on the periphery of our Galaxy, the Milky Way. We lived “nowhere in particular” in the Universe, in a stellar suburb.
Astronomy studied the evolution of the stars, biology the evolution of life on Earth; and the paths of their investigations met — or, rather, converged like two tributaries of a river. Astronomy took for its province the question of the incidence of life in the Universe, and theoretical biology lent its assistance to the task. Thus, in the middle of the twentieth century, CETI (Communication with Extraterrestrial Intelligence) came into being, the first program dedicated to the search for other civilizations.
But the search, conducted for several decades, utilizing ever better and more powerful instruments, found no alien civilization or any trace of a radio signal. So arose the enigma of the silentium universi. The “cosmic silence” received some publicity in the seventies, when it was taken up by the media. The undetectability of “other intelligences” was incomprehensible to scientists. The biologists had already determined what physical-chemical conditions facilitated the emergence of life from inert matter — and the conditions were not at all exceptional. The astronomers proved the existence of numerous planets around various stars. Observations indicated that a high percentage of the stars in our Galaxy had planets. The obvious conclusion was that life arose frequently in the course of ordinary cosmic changes, that its evolution should be a natural phenomenon in the Universe, and that the crowning of the evolutionary tree with the emergence of intelligent beings likewise belonged to the normal order of things. But, over the decades, the repeated failure to receive extraterrestrial signals, despite the increasing number of observatories that joined the search, contradicted this image of a populated cosmos.
According to the science of the astronomers, biochemists, and biologists, the Universe was full of stars like the Sun and planets like the Earth; by the law of large numbers, therefore, life should be developing on innumerable globes, but radio monitoring indicated, everywhere, a dead void.
The scientists who belonged to CETI and then SETI (Search for Extraterrestrial Intelligence) created various ad hoc hypotheses to reconcile the universal presence of life with its universal silence. At first they said that the average distance between civilizations equaled fifty to a hundred light-years. Later they had to increase the distance to six hundred and then to a thousand light-years. And there were hypotheses about the self-destructiveness of intelligence — such as von Hörner’s, which connected the psychozoic “density” of the Universe with its barrenness, claiming that suicide threatened every civilization, as nuclear war was now threatening humanity. The organic evolution of life took billions of years, but its final, technological phase lasted barely a few dozen centuries. Other hypotheses pointed to the dangers that the twentieth century encountered even in the peaceful expansion of technology, whose side effects devastated the reproductive capacities of the biosphere.
Someone said, paraphrasing the famous words of Wittgenstein, “Whereof one cannot speak, thereof one must make poetry.” Perhaps Olaf Stapledon, in his fantasy Last and First Men, was the first to express our destiny, in this sentence: “The stars create man, and the stars kill him.” At the time, however, in the 1930s, these words contained more poetry than truth; they were a metaphor, not a hypothesis qualifying for citizenship in the realm of science.
But any text can hold more meaning than its author gave it. Four hundred years ago, Francis Bacon contended that flying machines were possible, as well as machines that would speed across the Earth and travel on the sea bottom. He certainly did not conceive such devices in any concrete way; but we, reading his words today, not only know that they have come true but also expand their meaning with a multitude of details familiar to us, which only adds weight to his statements.
Something similar happened with the idea that I expressed at the American-Soviet conference of CETI in Burakan in the year 1971. (My text can be found in the book Problems of CETI, published by Mir in Moscow in 1975.) I wrote then:
If the distribution of civilizations in the universe is not a matter of chance but is determined by astrophysical conditions of which we are ignorant, though they may be observable phenomena, then there will be less chance of contact the stronger the connection is between the location of the civilization and the nature of its stellar environment — that is, the more unlike a random distribution is the distribution of civilizations in space. One cannot, a priori, rule out the possibility that there exist astronomically observable indicators of the presence of civilization… Consequently, the CETI program should also make allowance for the passing nature of our astrophysical knowledge, since new discoveries will influence and alter CETI’s most fundamental assumptions.
And that is exactly what happened — or, rather, what is slowly happening. As from the scattered pieces of a jigsaw puzzle, a new picture is emerging from new discoveries in galactic astronomy, from new models for the genesis of the planets and the stars, from the composition of radioisotopes recently found in meteors of the solar system. The history of the solar system is being reconstructed, and the origin of life on Earth, with an import as exciting as it is contrary to all we have accepted until now.
To put the matter most concisely: the hypotheses that reconstruct the past ten billion years of the Milky Way’s existence tell us that man emerged because the Universe is a place of catastrophe; that Earth, together with life, owes its existence to a peculiar sequence of catastrophes. It was as a result of violent cataclysms that the Sun gave birth to its family of planets. The solar system emerged from a series of catastrophic disturbances, and only after that could life arise, develop, and eventually establish dominion over the Earth. In the next billion-year period, during which man had no chance to emerge because there was no room on the evolutionary tree, another catastrophe opened the way for anthropogenesis by killing hundreds of millions of Earth’s creatures.
Creation through destruction (and consequent release of tensions) occupies the central place in this new picture of the world. Or one could put it thus: Earth arose because the proto-Sun entered a region of destruction; life arose because Earth left that region; man arose because in the next billion years destruction once again descended on Earth.
Stubbornly opposing the indeterminism of quantum mechanics, Einstein said, “God does not play dice with the world.” By this he meant that chance cannot decide atomic phenomena. It turned out, however, that God plays dice not only on the atomic scale but with the galaxies, the stars, the planets, the birth of life, and the emergence of intelligence. We owe our existence as much to catastrophes that occurred at the right place and the right time as to those that did not take place in other epochs and places. We came into the world having passed — during the history of our star, then of the planet, then of biogenesis and evolution — through the eyes of many needles. The nine billion years separating the protosolar cloud of gases from Homo sapiens can therefore be compared to a gigantic slalom in which no gate was missed. We know now that there were many such “gates,” and that any veering from the slalom run would have precluded the rise of man. What we do not know is how “wide” was this track, with its curves and gates — or, in other words, the probability of this “perfect run” whose goal was anthropogenesis.
So the world that the science of the next century will recognize will be a group of random catastrophes, creative as well as destructive. Note that the group is random, whereas each of the catastrophes in it conforms to the laws of physics.
I
In roulette, losses are the rule for the vast majority of players. Otherwise, every Monte Carlo-type gambling casino would quickly go bankrupt. The pl
ayer who leaves the gaming table with a profit is the exception to the rule. The one who wins often is a rare exception, and the one who makes a fortune because the ball lands on his number almost every time is an extraordinary exception; his incredible luck is written up in the papers.
A player can take no credit for a run of wins, because there is no betting strategy that will guarantee a win. The roulette wheel is an instrument of chance; that is, its end states cannot be predicted. Since the ball always stops at one of thirty-six numbers, the player has one chance out of thirty-six to win in every game. The player who places his bet on the same number twice has one chance in 1,296 to win twice, because the probabilities of chance events not interdependent (as on the roulette wheel) must be multiplied by one another. The probability of winning three in a row is 1:46,656. The chance is very small, but it is calculable, because the number of end states of every game is the same: thirty-six. If, however, in calculating the player’s chances, we wished to take into account incidental phenomena (earthquakes, bomb attacks, the player’s death from a heart attack, etc.), the task would become impossible. Similarly, when someone picks flowers in a meadow under artillery fire and returns home safe, bouquet in hand, his survival cannot be put into statistical form, either. It cannot be done, although the incalculability — and, therefore, the unpredictability — has nothing to do with the kind of unpredictability that characterizes quantum-atomic phenomena. The fate of the flower picker under fire could be made a statistic only if there were very many flower pickers, and if, in addition, the distribution of the flowers in the meadow were known, and the time of their picking, and the average number of shells per unit of shelled surface.
The determination of this statistic is complicated, moreover, by the fact that the shells that miss the picker destroy flowers, thereby changing their distribution in the meadow. The picker who is killed is dropped from the game of picking flowers under fire, just as the roulette player who was lucky at the start but then lost his shirt is dropped.
An observer watching the group of galaxies for billions of years could treat them like roulette wheels or meadows with flower pickers and discover the statistical laws to which the stars and planets are subject. From that, he would be able to establish how often life appears in the Universe and how often it evolves to the point where intelligent beings arise.
Such an observer could have been a long-lived civilization — or, more precisely, successive generations of its astronomers.
If, however, the meadow with flowers is shelled in a chaotic fashion (which means that the density of shots does not fluctuate around a certain average and therefore is not calculable), or if the roulette wheel is not “honest,” then even such an observer will not be able to determine the statistics of the frequency of intelligence in the Universe.
The impossibility of determining such a statistic is practical rather than theoretical. It does not lie in the nature of matter itself, like the Heisenberg uncertainty principle, but “only” in the incalculable overlapping of different random series, which are independent of one another and take place on varied scales of magnitude: galactic, stellar, planetary, and molecular.
A galaxy treated as a roulette wheel on which life can be “won” is not an “honest” roulette wheel. An honest roulette wheel manifests one and only one probability distribution (1:36 for each play). For roulette wheels that are shaken, that change shape during the game, that keep using different balls, there is no such statistical uniformity. All roulette wheels and all spiral galaxies are certainly similar to one another, but they are not exactly the same. A galaxy can behave like a roulette wheel placed near a stove; when the stove is hot, the heat will distort the disk, which will, in turn, affect the distribution of the winning numbers. A brilliant physicist can measure the influence of temperature on the roulette wheel, but if, in addition, the floor shakes from the trucks outside, his measurement will be off.
In this sense, the galactic game of life and death is a game played on a loaded roulette wheel.
Earlier, I referred to Einstein’s belief that God does not play dice with the world. I can now expand on what I said there. God not only plays dice with the world, he also plays an honest game — with perfect, identical dice — but only on the smallest scale, the atomic. Galaxies, on the other hand, are huge divine roulette wheels that are not honest. Please note that “honesty” here is understood mathematically (statistically) and not morally.
Observing a radioactive element, we can establish its half life — that is, how long one has to wait for half its atoms to decay. This decay is governed by statistically honest chance, since it is the same throughout the Universe for this element. Whether it sits in the laboratory, in the depths of the Earth, in a meteor, or in a cosmic nebula, its atoms behave the same way.
Whereas a galaxy, a mechanism that produces stars, planets, and occasionally life, does so — as a mechanism of chance — dishonestly, because incalculably.
Its creations are governed neither by determinism nor by the sort of indeterminism we find in the world of quanta. Therefore the course of the galactic “game for life” can be known only ex post facto, after we have won. One can reconstruct what has taken place — although it was not, in the beginning, foreseeable — but not with exactitude; it is like re-creating the history of human tribes in the era when people were still illiterate and left behind no chronicles or documents, only the work of their hands, which the archaeologist unearths. Galactic cosmology then becomes “stellar-planetary archaeology.” This archaeology studies the particular game whose winning stake is us.
II
A good three-quarters of the galaxies, like our Milky Way, are spiral disks with a nucleus and two arms. This galactic formation of gaseous clouds, dust, and stars (which gradually are born and die in it) revolves, its nucleus whirling at a greater angular velocity than the arms, which, falling behind, bend, thereby giving the whole the shape of a spiral.
The arms, however, do not move at the same speed as the stars.
A spiral galaxy owes its unchanging form to its density waves, in which the stars behave like molecules in an ordinary gas.
Orbiting at different speeds, the stars that are considerably removed from the nucleus remain outside the arm, while those near the nucleus overtake and pass through the spiral arm. Only the stars halfway out from the nucleus move at the same velocity as the arms. This is the so-called synchronous (corotational) circle. About five billion years ago, the cloud of gases from which the Sun and the planets were to form was situated near the inner edge of a spiral arm. It overtook that arm slowly — on the order of one kilometer per second. The cloud, entering deep into the density wave, became contaminated by isotopes of iodine and plutonium, the radioactive residue of a supernova that had exploded in the vicinity. The isotopes decayed, until another element, xenon, was formed from them. Meanwhile, the cloud was compressed by the density wave in which it moved, and this caused condensation until a young star — the Sun — arose. At the end of this period, some four and a half billion years ago, another supernova exploded in the neighborhood; it contaminated the circumsolar nebula (not all the protosolar gas had been concentrated yet in the Sun) with radioactive aluminum. This hastened, perhaps even caused, the emergence of the planets. Computer simulations show that, in order for a disk of gases whirling around a young star to undergo segmentation and condense into planets, some outside intervention is necessary, like the giant push supplied by the supernova that exploded not far from the Sun.
How do we know all this? From the composition of radioisotopes in the meteors of the solar system. Knowing the half life of the isotopes of iodine, plutonium, and aluminum, we can calculate when the protosolar cloud was contaminated by them. This took place at least twice; a different time of decay enables us to establish that the first contamination took place shortly after the protosolar cloud entered the inner edge of the galactic arm, and the second contamination (by radioactive aluminum) occurred some three hundred million
years later.
The Sun, therefore, spent the earliest phase of its development in a region of strong radiation and shock waves that caused the formation of the planets; then, accompanied by the already cooling and solidifying planets, it left that zone. It came out into a region of high vacuum free of stellar catastrophes; thus life was able to develop on Earth without lethal disturbances.
This picture puts a big question mark over the Copernican idea that says the Earth (together with the Sun) does not occupy a special, favored place, but a “typical” one.
Had the Sun been on the far periphery of the Galaxy and, traveling slowly, not crossed a spiral arm, it certainly would not have formed the planets. Planet formation requires “midwife assistance” in the form of violent events, such as a shock wave from an exploding supernova (at least one).
Had the Sun, in giving birth to the planets, been close to the galactic nucleus, thus traveling faster than the arms of the spiral, it would have passed through them often. Frequent irradiations and shocks would then have made the emergence of life on Earth impossible, or would have destroyed it in an early phase of development.
Similarly, had the Sun orbited at the exact corotational point of the Galaxy, never leaving its arm, life would also not have been able to establish itself on our planet. Sooner or later it would have been killed by a neighboring supernova (supernovas explode most often within the galactic arms). Also, the average distance between stars is considerably smaller within the arms than between the arms.
One Human Minute Page 8
