THE FERMI PARADOX AND EARTH'S FUTURE

THE IMPLICATIONS OF THE FERMI PARADOX

Enrico Fermi, the Italian-American theoretical physicist, sometimes referred to as the "father of the atomic bomb" was winner of the Nobel Prize (1938 Physics) and who,with his colleagues, built the first atomic reactor at the University of Chicago in 1942. Fermi had a facile mind and was fond of making rough mathematical estimates off the top of his head. In the post-war era, Fermi worked on the hydrogen bomb project in Los Alamos, New Mexico. It was about this time that a particularly active spate of UFO sightings were reported in the USA. They all proved to be ruses, or to be of explicable atmospheric or terrestrial origin. About the same time, in New York, in 1950, cartoonist Alan Dunn published a comical piece in the New Yorker magazine implying that the bane of the suburban homeowner,the lost or missing garbage pail cover was really the work of “aliens” from space who needed them to make flying saucers. Only a short time after the cartoon's appearance Fermi and several of his colleagues, while walking to lunch, took the opportunity to discuss this amusing matter in a lighthearted way. As the scientists bantered, Fermi thought in silence. When the jokes ended, he turned serious as he asked his scientist friends "So where are all the ailiens?” or "Where is everybody?". As a response to their quizzical expressions, he explained that his rough calculations indicate a high probability of extraterrestrial, sentient life and of advanced civilizations. He based his conclusions on the fact of the non-unique character of the Earth, the young age of the Sun (and Earth) and the immense number of stars in the galaxy and the universe. Thus, he concluded, there was a high probability for the existence of other planets with earth-like conditions where civilizations should have had plenty of time to have reached and surpassed the Earth's level of technology and sophistication and had time to embark on space voyages of exploration and colonization. But, he added, why are there no credible evidences of other worldly civilizations? The only evidences were imaginings such as UFOs and Dunn's cartoon about trash can covers. Fermi concluded by posing the now famous question, "Where is everybody?"

Fermi's query underscores the serious conflict, the paradox, between our knowledge of the physical world and the expected probability and path of events likely to occur, against the lack of evidence of those events in our earthy experience.

As they walked on, Fermi fleshed out his hypothesis with some rough figures. He pointed out that scientists assume that the Earth is a typical planet, orbiting an average-sized young star, the Sun. The Sun is located in the outer rim of our galaxy, known as the Milky Way. Our star is just one of some 200 to 400 billion or more other stars in our galaxy. But beyond the Milky Way we can see the swirling lenticular patterns of other galaxies in the visible universe, an estimated 80-100 billion of them. Each one of those billions of galaxies are comprised of stars as is our Milky Way. Galaxies vary in size, making precice eatimates of the total number of stars in the visible universe difficult. A recent estimate, December 2010, (by Pieter Van Dokkum in Nature) indicates that there may be more than 300 sextillion stars in the visible universe. (Note: that number is 3 x ten to the 26th power, or 300 followed by 24 noughts or zeros) Even if only a very tiny percentage of all those stars had planets with an earth-like range of temperatures, certain gases in its atmosphere, specific geological processes going on, and surface processes in which chemical elements could combine into simple molecules, each with the ability to reproduce themselves, generating "progeny" with minor chance-induced variations. Once reqching that stage, the grand process of Darwinian evolution would initiate and proceed to engender more and more well-adapted forms. The number of specific requirements, each one dependenpt upon the previous, and also necessary to occur in a certain order make the probability of occurrence for these circumstances to be indeed very low and for these multiple events to initiate on each of the Earth-like planets only adds to the difficulty. Perhaps there is only a probability of one in a billion (I am guessing here!) yet the sheer number of stars, 300 sextillion or almost an infinite number available, overmatches these low probabilities. Of those planets with earthy conditions many would follow Earth's course toward sentient life and would go on to develop technological sophistication. Given what we know from our own Earth we would expect advanced civilizations to develop similar to our own. Furthermore, since the Sun is a young star at only 4.5 billion years old, while the known universe is more than three times older (at about 14 billion years) and thus these "other earthly" civilizations might be well along in their evolution toward space travel and universe colonization, being far ahead of our own recent feeble attempts. Fermi reasoned that these extraterrestrial civilizations, many of which could have existed millions or even billions of years prior to our own Sun's birth, would have more than adequate time to explore and colonize other parts of the universe, making their presence known to us.

But according to Fermi, as diligently as we have sought and searched (such as efforts by SETI, Search for Extraterrestrial Intelligence, at Berkeley U of C) the heavens, we have so far found no proof of other life forms. In spite of the number of UFO reports, pseudo-scientific imaginings of alien landings, reports of flying saucers, etcetera, there have been no credible evidence of extraterrestrial life or visits. Why? According to all that we know of the universe and what we know of mathematical probability they should be there or have revealed their presence to us by this time. But they have not. Where are they? This is the basis of Fermi's question: "Where is everybody?".

If we accept the basis of Fermi's Paradox, we are inexorably led to examine more closely its significant implications.

The first might be, that we find no evidence of extrqterrestrial life because life is scarce and more difficult to develop "from scratch" than we expect and that the are no other advanced or sentient life forms or civilizations out there. We are alone in the universe. This line of reasoning posits that the development of life and civilization on earth is the result of the exceedingly rare concatenation of unlikely circumstances. One such example is the chance impact near present day Chicxalub, Mexico by an asteroid at the close of the Cretaceous Period, some 66-67 million years ago. The large Chicxulub asteroid (on impact formed a 6 mile deep, 100 plus mile wide crater off the Yucatan Peninsula) just happened to impact Earth at a critical time for the evolution of mammals. Its impact caused severe world wide environmental effects, so as to cause the mass extinction of a dominant life form of the Cretaceous Period the dinosaurs. This event seemingly would alter the biosphere to make way for the explosive adaptive radiation of a group of tiny, inconspicuous, nocturnal,insect-eating mammals (a large species was the size of a squirrel) which, with the demise of the saurians had new habitats and food resources to exploit. This is the quirky, "chancy" way by which life evolved on Earth. Earth's course of evolution could have just as easily gone some other way had the Chicxulub asteroid missed us by a hair. It would seem that such lucky strokes of nature are very rare and unlikely to be repeated again and again on other distant planets. However, a truism of astrophysics is that all things are possible given enough time and enough stars near where they might occur, and our universe has no scarcity of either one. Thus such an hypothesis (our specialness or uniqueness) seems to fly in the face of all we know about the physical world and the mathematics of probability.

A second possibility advanced to explain the lack of evidence of human-like neighbors in the universe is more ominous for us. Perhaps life and civilizations are as common as Fermi suspected. Perhaps life has formed many, many times before on other distant planets, but given the nature of such life, encoded as it is with the traits necessary to exploit and survive in a harsh environment, and to become a dominant life form--the inherent greed, rapacity, the need to conquer, and the development of exploitative interrelations among their own kind, ultimately lead to conflict, chaos, exploding populations, population collapse and extinction.

Is the answer to the question Fermi posed:“Where is everybody?"--that they have existed once, but have all gone to hell? Is the natural end of planets like ours, which are able to develop and harbor "sentient" life and "civilization" that in the end, they get snuffed out in a global nuclear holocaust, starved to death, or burned to a crisp on a planet with Venus-like high levels of heat-absorbing carbon dioxide in its atmosphere, generating a run-away greenhouse effect?

We are now in the 21 Century on they very cusp of a significant change in human development and direction. Our course from here can lead us toward one end or another. One route takes us on to conflict, nuclear war, chaos, starvation and global warming. The other, more hopeful course, may give us time to progress and evolve further, both socially and technologically, and ultimately lead toward peaceful exploration of space. What will be our future?

Are we Earthlings wise enough to understand the implications of the Fermi Paradox?

Get the picture?

rjk