November 2012


Are We Alone in the Universe?

By Ronald Bleier

When I learned, as a high school student, that our universe was populated by billions of galaxies, many of which are similar to our own Milky Way Galaxy, it seemed logical to suppose that the laws of chance alone would be sufficient to produce perhaps a large number of examples of alien civilizations. In those heady post WWII years, I had little doubt that earthling destiny incorporated and was given purpose by inter-stellar and perhaps also inter-galactic travel. By no means, I believed, were our frontiers restricted to our own solar system.

My optimism in those days was such that I produced a facetious theory to deal with the difficulty of traversing the vast distances of space. I proposed that Einstein must have been wrong to limit human speeds of travel to a fraction of the 186, 000 miles per second turtle-like speed of light. Subsequently theoretical physics arrived to support my earlier daydreams in the form of theories that wormholes -- shortcuts through spacetime -- might make intergalactic travel possible, at least notionally

But in 1985 I happened upon an article in Astronomy magazine entitled "Intelligent Life in Space," by Professor Edmund Olson which completely overturned my views. That one article was sufficient to convince me that it was not unlikely that our own technological civilization might be the only one in existence. Furthermore I soon came to recognize that the enormous distances separating stars and planets in outer space make it practically impossible that humans will ever conduct space exploration beyond our solar system.

The October 2012 discovery of a planet orbiting one of the stars of our sun's nearest neighbors, the triple star system Alpha Centuri, about 4.4 light years away, spurred media attention to the possibilities of human interstellar exploration. A New York Times article on the subject emphasized the great distances and the challenging, if not insurmountable, logistics involved in sending even a tiny cell phone-sized probe to the Alpha Centuri system. For example, merely PLANNING to send such an instrument to Alpha Centuri B -- the star with the newly discovered planet -- would take about a hundred years, although some hope that this could be shortened.1 The Times noted, by the way, that the newly found planet, named Alpha Centuri Bb, is so close to its huge star that it is an uninhabitable 2,192° F (1,200° C ).

After the planning period, the 27 trillion mile trip itself would require 78,000 years if a probe headed in that direction were to travel at 11 miles per second. Such a speed would match our fastest and most distant spacecraft, Voyager 1, which was launched in 1977 and some 35 years later is about 11 billion miles away, fairly close to escaping the sun's influence. The Times assures us, however, that travel time to Alpha Centuri could be cut to less than a human lifespan if schemes employing existing or new and developing technology -- including solar sails and thermonuclear rockets -- pan out.

Physicist and best-selling science writer, Dr. Mitchio Kaku, undoubtedly speaking for many, argues that it is arrogant to think that intelligence is limited to our own planet. But there may be another kind of arrogance at play: the anthropomorphic view that our intelligence is important enough to be commonly replicated.

The possibility that we may be alone in the universe may be of more than academic interest in that it helps to focus attention on critical issues concerning the survivability of our civilization. As we move past the first decade of the 21st century, it's becoming clearer that limits to resources, the deterioration of our environment, and the unpredictable political effects of rising per capita scarcity seriously threaten the long term and even short term existence of our modern technological civilization.

It seems more evident now that such phenomena as overpopulation, global warming, species extinction, loss of forest cover and diminishing rainforests, the disappearance of glaciers, the rise of invasive species, the intractability of the nuclear waste problem, the Malthusian requirement for war and violence, including the increasingly menacing possibility of nuclear war, are some of the significant signs that our social order is all too rapidly crashing into impassable political and environmental barriers.

Points to consider

The bulk of Professor Olson's article is devoted to critically examining the famous Drake equation (see below), a formulation based on the theory that alien intelligence is likely to be a common occurrence. The key point underlying Olson's article is that we need to take seriously the alternative possibility that we are indeed alone in the universe. Two critical themes in Professor Olson's article, summarized below, deserve special emphasis:
1. Life in the universe is not as prevalent as we might think.
2. Cognitive intelligence is not a necessary or even a desirable survival trait.

In addition, there are two other considerations that make the possibility of human contact with an alien civilization less likely in the lifetime of our civilization.

The first is that there is not necessarily a high probability that our brief instant of awareness as a technologically advanced society will coincide with the flower of an alien culture that could make their presence known to us. For example, if aliens were to encounter our planet even as soon as 500 years from now, there may not be any intelligent beings available with whom they could dialogue. Or had extra-terrestrial visitors landed on earth 500,000 or a million years ago, they would have undoubtedly been fascinated with our flora and fauna but there would not have been any anatomically modern humans with whom aliens could have communicated.

Secondly, if a small or large number of technological civilizations had arisen capable of interstellar travel, it's not at all unlikely that they would have made their presence known by this time.2 Since they haven't yet given such unequivocal evidence, it's possible that if such societies existed they may have faced similar struggles over limited and finally exhausted resources. In such cases they may never have reached a level sufficiently advanced to explore regions in space much beyond their own localities. They may have fallen back, as we may do, into internecine struggle, decay and oblivion.

In light of such difficult realities and dim projections, the urgency of uniting our talents and devoting our remaining resources toward achieving sustainability here on earth is manifest. Roman civilization and countless others, great and small, couldn't manage it. But our task must surely be to find our way.


Edward Olson's "Intelligent Life in Space" summarized

Olson begins by re-stating the common sense notion that given the enormous number of stars in our galaxy, it is reasonable to assume that many must have planets which could host life and that some fraction of them must harbor technological civilizations. Olson writes that the principle behind this thinking goes back to the Copernican idea that there is nothing special about life on earth and therefore there are likely to be other intelligent civilizations in our galaxy capable of communicating with us.

Professor Olson cites a book by Carl Sagan and I.S. Shklovskii published in 1966, Intelligent Life in the Universe which spurred many to predict N, the number of technological communicating civilizations present in our galaxy. Many astronomers and a few biologists have expressed differing degrees of optimism about N.

Olson introduces the Drake equation which was conceived as a way of assigning a value to N, the number of extraterrestrial civilizations. It defines N as the product of a series of probabilities. Included in the equation are such elements as the rate of star formation, the number of stars believed capable of supporting advanced organisms on surrounding planets, and five more related variables.3

The ability to put numbers, however uncertain, into this equation lends an air of plausibility to the exercise. Optimistic estimates for these quantities yields the high figure for N of 100,000 technological cultures in our galaxy that remain active for a million years. Pessimistic estimates range as low as one, our own.

As Olson sees it, the problem with the optimistic inputs into the Drake equation and indeed into the idea behind the equation itself, is that the chemical, biological, evolutionary, anthropological, and sociological factors are extremely complex and it is difficult to assign numbers to them. Olson quotes the chemist Richard E. Dickerson who remarked that proposing scenarios for the origin of life is one thing, but it is quite another to "demonstrate that such scenarios are either possible or probable."

The bulk of Olson's article is devoted to an alternate view of the probability of extra terrestrial life in our galaxy. Olson emphasizes the randomness and improbability of the repetition of the great experiment that has taken place on Earth. He tackles the subject by going beyond sheer numbers and by considering some of the biological issues that make it less rather than more likely that intelligent beings comparable to homo sapiens have ever existed or are likely to exist currently or to be in a position to contact our modern civilization.

Olson considers the probability that life will appear elsewhere in the galaxy on a favorable planet. Optimists note that since "some `life-precursor' organic molecules have been observed in highly improbable places, like interstellar molecular clouds and carbonaceous meteorites, their synthesis on planetary surfaces is plausible." And indeed scientists have concluded that "even under the mildly reducing conditions now regarded as probable in the early terrestrial atmosphere, molecules as complex as certain amino acids could form readily."

From this, optimists jump to the conclusion that the synthesis of amino acids is vital for life to begin. But laboratory experiments highlight the fact that we are very far away from understanding the critical step in the formation of life, "the actual origin of a replicating system" much less duplicating the inception of life itself in our laboratories.

If chemists in their laboratory experiments cannot give us a value for the possibility that life will appear on every suitable planet, what then does the geological record show? "The micro-fossil record suggests that primitive cells were present within a billion years or less of Earth's formation." Does this suggest that life is close to appearing on every suitable planet? Perhaps. However, biologist Leonard Ornstein has argued, "from life's exclusive use of L-symmetry molecules, that life may have originated only ONCE on Earth, and that from a single event no statistical conclusions can be drawn" (my emphasis). Life could happen on every suitable planet or could be as low as any value down to the infinitesimal. "Ornstein likes the value 10-6. Others are less pessimistic, but if the argument developed below is correct, it may not matter."

When we turn to the probability that life, once begun, inevitably evolves to cognitive intelligence, we face questions of biological evolution. Olson writes of our tendency to believe that "intelligence has survival value and that evolution by natural selection tends to produce more complex species of life. Can we not therefore be optimistic about life elsewhere?"

The difficulty, Olson argues, is that natural selection contains no "self-perfecting" principle that guarantees a particular outcome such as intelligence. Olson argues that mammals, including primates, would never have existed had not a complex and diverse environment, with its associated food chain, evolved to support them. Hence, "the evolutionary process is more subtle than the operation of some law of nature which unfailingly generates complex intelligent creatures."

Olson calls the next section of his article "Factoring fi" (life leading to cognitive intelligence) where he details five critical Precambrian4 biological inventions, including anaerobic photosynthesis and the manufacture of new amino acids that were all necessary to evolution. He elaborates some of the necessary steps that led to intelligence and he asks: "Would something like them occur on other planets? ... These were laborious inventions, each taking, in round numbers, half a billion years to achieve. One can hardly say that they were either pre-ordained or even particularly likely to occur in another setting."

On the critical transition of life on earth from the ocean to the land, Olson quotes Loren Eiseley, a well known science writer, who wrote that the transition which developed during the post Cambrian period "was not the magnificent march through the breakers and up the cliffs that we fondly imagine. It was a stealthy advance made in suffocation and terror, amidst the leaching bite of chemical discomfort." And Olson points out that "any one of a large number of environmental particulars could have delayed -- even aborted this crucial step [toward cognitive intelligence]".

Olson then explores some of the steps that led from landed animals to Homo sapiens. Critical was the "rise of angiosperms, flowering plants whose origin Darwin termed an `abominable mystery'... With flowering plants came nectars and pollens, insect pollination, and -- above all -- fruits and seeds which concentrated food energy to previously unknown degrees." He speaks of the rise and demise of the dinosaurs, the advent of warm-blooded mammals, tree-dwelling primates, protohumans, bipedalism and finally cognitive intelligence.

"The human brain appears to have arisen in part because it improved the chances of living through a very specific sequence of environmental changes. It does not seem likely that the evolution of intelligence was a sure thing...the probability of its occurrence elsewhere ... is not likely to be even close to unity."

Thus, added to the five critical Precambrian factors in life's evolution, Olson cites "at least six pivotal developments" in the post Cambrian period that led to intelligent beings. Olson argues that these eleven steps are the minimum necessary to yield cognitive intelligence and "more knowledgeable writers would add to the list and expand on the simple arguments presented here" and that all these steps were contingent developments and not inevitabilities.

DNext, Olson raises the question of the survival value of intelligence and challenges the common notion that intelligence implies survival. He points to cases in the record where more intelligent species failed to compete successfully against less intelligent animals. Olson emphasizes that while it may be surprising to us, intelligence doesn't necessarily aid survival in general.

Olson makes the point that while this discussion doesn't necessarily imply that life is rare in the universe, "even after life begins on a planet, evolves energy sources, becomes complex -- even after all that -- communicating across the interstellar void may have low probability."

Do we have any way to broaden our sense of the possibilities of cognitive intelligence developing on a planet that can support life? To answer this question, Olson cites Loren Eisely's discussion of examples on earth of other "worlds" which provide examples of alternative evolution. He points to Australia and South America which, as a consequence of continental drift, separated from the huge landmass we call Pangaea some 200 million years before the emergence of mammals. In Australia there is "no hint of the emergence of intelligent mammals like the primates." In South America we have monkeys but "there are no great apes in the New World, no evidence of ground-dwelling experiments... Here ended another experiment which did not lead to man, even though it originated within the same order from which he sprang."

One conclusion we can draw is that in both cases, the environment didn't provide the proper ecosystems. Olson emphasizes that natural selection merely tracks the environment; the process does not guarantee intelligence as its final product.

Estimating N from the Expanded Drake Equation

With this discussion in mind, Olson is ready to factor in the biological probabilities into the Drake Equation. Bearing in mind notions that there is nothing inevitable about cognitive intelligence, and at the same time assigning "generous" estimates to some of the biological uncertainties, Olson provides a new set of numbers for N that are not optimistic. In his new equation:

N = 6 x10-7 x L

where L is the communicative lifetime of a civilization. If L is roughly a million years, Olson writes, "then we are the only technological civilization in two Milky Way spiral galaxies. If L is only 100 years, then we are unique among 20,000 such galaxies."

Olson warns that his "pessimistic" conclusion is still theoretical and admittedly quite speculative. It ignores, for example, alternate biologies." He reminds us, however, that if we are indeed alone in the universe, "such an outcome could carry far deeper implications for us than would a galaxy full of other chattering civilizations." He quotes James Trefil who wrote that "[I]f we succeed in destroying ourselves, it will be a tragedy not only for the human race but for the entire Galaxy, which will have lost the fruit of a 15-billion year experiment in the formation of sentient life."

Olson concludes by quoting one of his students, Sally Green. "I walk away from here with a delightful reverence for the amazing, chancy development of carbon-based life on this planet ... we are caretakers of the most fragile bloom in the universe."5


1Dennis Overbye, "Discovery Rekindles Wish for a Journey to the Stars," New York Times, October 22, 2012 arrow

2A theory similar to Fermi's paradox - the conjecture that since aliens have left us no evidence of their visits, they don't exist. arrow

3Frank Drake, Professor of Astronomy and Physics at the University of California, Santa Cruz. devised his equation in 1961. N = R x fG x nCHZ x fL x fi x fT x L -- where N is the number of technological communicating civilizations present in our galaxy,
R is the rate of star formation per year,
fG the number of stars like our sun believed to be capable of supporting advanced organisms on surrounding planets,
nCHZ is the number of planets in the continuously habitable zone per suitable star,
fL is the fraction of those planets on which life begins,
fi the fraction of life-bearing planets that produce cognitive intelligence,
fT is the fraction of intelligent civilizations that develop both the technology and desire for interstellar communication and L is the lifetime that such planets communicate. arrow

4The Pre-Cambrian era is the period from the time the earth was formed 4.6 billion years ago to the period known as the Cambrian explosion -- dated at 543 million years ago. The Cambrian period is remarkable for the production of an astonishing array of multicellular animals. arrow

5 Professor Olson provides a list of books and articles for further reading. Among them he offers:
Leonard Ornstein. "A Biologist Looks at the Numbers," Physics Today, March 1982.
Robert Rood and James S. Trefil. Are We Alone? Charles Scribner's Sons, New York, 1981.
R.A. Schorn. "Extraterrestrial Beings Don't Exist," Sky and Telescope, September 1981.
A more recent title on the same theme is John Gribbin's: Alone in the Universe: Why Our Planet Is Unique (2011).


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