REVIEW: FERMI PARADOX


The galaxy contains roughly a hundred billion stars. If even a very small fraction of these have planets which develop technological civilizations, there must be a very large number of such civilizations. If any of these civilizations produce cultures which colonize over interstellar distances, even at a small fraction of the speed of light, the galaxy should have been completely colonized in no more than a few million years. Since the galaxy is billions of years old, Earth should have been visited and colonized long ago. The absence of any evidence for such visits is the Fermi Paradox.

The Fermi Paradox is a physical paradox in which high estimates of the probability of the existence of extraterrestrial life are contrasted with a lack of evidence.

The age of the universe and its vast number of stars seem to suggest that extraterrestrial life should be common. Considering this with colleagues over lunch in 1950, the physicist Enrico Fermi is said to have asked: “Where are they? If there are a multitude of advanced extraterrestrial civilizations in the Milky Way galaxy then why have we not seen any evidence, such as probes, spacecraft or radio transmissions? The simple question “Where are they?” (alternatively, “Where is everybody?”) is possibly apocryphal but Fermi is widely credited with simplifying and clarifying the problem of the probability of extraterrestrial life.

There have been attempts to resolve the Fermi Paradox by locating evidence of extraterrestrial civilizations, along with proposals that such life could exist without our knowledge. Counterarguments suggest that intelligent extraterrestrial life does not exist or at least occurs so rarely that we will never make contact with it. The belief that the lack of evidence conclusively demonstrates the non-existence of extraterrestrial civilizations is known as the Fermi principle.

A great deal of effort has gone into developing scientific theories and possible models of extraterrestrial life and the Fermi paradox has become a theoretical reference point in much of this work. The problem has spawned numerous scholarly works addressing it directly, while various questions that relate to it have been addressed in fields as diverse as astronomy, biology, ecology and philosophy. The emerging field of astrobiology has brought an interdisciplinary approach to the Fermi paradox and the question of extraterrestrial life.

The Fermi paradox is a conflict between an argument of scale and probability, and a lack of evidence. A more complete definition could be stated thus:

    The size and age of the universe incline us to believe that many technologically advanced civilizations must exist. However, this belief seems logically inconsistent with our lack of observational evidence to support it. Either the initial assumption is incorrect and technologically advanced intelligent life is much rarer than we believe, our current observations are incomplete and we simply have not detected them yet, or our search methodologies are flawed and we are not searching for the correct indicators.

The first aspect of the paradox, “the argument by scale”, is a function of the raw numbers involved: there are an estimated 250 billion stars in the Milky Way and seventy sextillion (7 x 1022) in the universe. Even if intelligent life occurs on only a minuscule percentage of planets, there should still be a great number of civilizations extant in our galaxy alone. This argument also assumes the mediocrity principle, which states that Earth is not special, but merely a typical planet, subject to the same laws, effects, and likely outcomes as any other world. Some estimates using the Drake equation support this argument, although the assumptions behind those calculations have themselves been challenged.

The second cornerstone of the Fermi paradox is a rejoinder to the argument by scale: given intelligent life’s ability to overcome scarcity, and its tendency to colonize new habitats, we have assumed that any advanced civilization would seek out new resources and colonize first their solar system, and then surrounding solar systems. As there is no evidence on Earth or anywhere else of attempted alien colonization after 13 billion years of the universe’s history, we must assume that intelligent life is rare in our part of the galaxy, or that our assumptions about the general behavior of intelligent species is flawed.

Several writers have tried to estimate how fast an alien civilization might spread through the galaxy. There have been estimates of anywhere from 5 million to 50 million years to colonize the entire galaxy; a relatively small amount of time on a geological scale, let alone a cosmological one. Even if colonization is impractical or undesirable to an alien civilization, large scale exploration of the galaxy is still possible with minor investment in energy and resources. The means of exploration and theoretical probes involved are discussed extensively below.

Drake Equation

While numerous theories and principles attend to the Fermi paradox, the one most closely related is the Drake equation. It was formulated by Dr. Frank Drake in 1960, a decade after the objections raised by Enrico Fermi, in an attempt to find a systematic means to evaluate the numerous probabilities involved in alien life.

The Drake equation has been used by both optimists and pessimists, with varying results. Dr. Carl Sagan, for example, suggested as many 1 million communicating civilizations in the Milky Way in 1966, though he later wrote in his widely known book Cosmos that said number could be far smaller. Other published estimates from Frank Tipler place the value at just one – e.g., human beings are the only extant intelligent life.

Critics of the Drake equation claim that since the variables cannot yet be determined with any real confidence, estimating the number of extraterrestrial civilizations based on it is methodologically flawed, an idea which the wide divergence in estimates seems to support. Focusing on empirical data – which scientists are only now beginning to collect and analyze in a significant manner – rather than theory is the only sound approach. Only with further observation can meaningful values for the Drake equation factors be assigned.

The Rare Earth Hypothesis attempts to resolve the Fermi paradox by suggesting that Earth is not typical, but unusual, and perhaps even unique. This is a rejection of the mediocrity principle and supports the Fermi principle – that a lack of evidence equals a lack of extraterrestrial life. While a unique Earth has had historical support on philosophical or religious grounds, the Rare Earth Hypothesis deploys quantifiable and statistical arguments in support of the theory that multicellular life is exceedingly rare in the universe because Earth-like planets are themselves exceedingly rare. Supporters argue that many improbable coincidences have converged to make complex life on Earth possible.

Insofar as the Rare Earth Hypothesis privileges Earth-life and its process of formation, it is a variant of the anthropic principle. The Anthropic Principle notes that the universe seems uniquely suited to the development of human intelligence and that any variation in any one of a myriad of universal constants would make the development of intelligent life more difficult. This philosophical stance opposes not only “mediocrity”, but the Copernican principle more generally, which suggests there is no privileged location in the universe.

Opponents dismiss both Rare Earth and the anthropic principle as tautological – if a condition must exist in the universe for human life to arise, then the universe must already meet that condition, as we are here – and as an unimaginative argument. According to this analysis, the Rare Earth hypothesis confuses a description of how life on Earth arose with a uniform conclusion of how life must arise. While the probability of the specific conditions on Earth being widely replicated may be low, complex life may not require exclusively Earth-like conditions in order to evolve.

Continued
HERE IS ANOTHER GOOD LINK

FERMI PARADOX

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About bruceleeeowe
An engineering student and independent researcher. I'm researching and studying quantum physics(field theories). Also searching for alien life.

7 Responses to REVIEW: FERMI PARADOX

  1. dad2059 says:

    Another good treatise on the Fermi Paradox is this one by transhumanist George Dvorsky; http://www.sentientdevelopments.com/2007/08/fermi-paradox-back-with-vengeance.html

    I just read another paper a couple of days ago about the Fermi Paradox is which several scenarios were put forward on why we see no evidence of ETI, but I’ll be damned if I can’t locate the link!

    The paper is eleven years old, but it’s a goodie. I’ll post it as soon as I find it.

    My take on it is about the same as Dvorsky’s, only I tie it in with the UFO phenomenon and Bostrum’s Simulation Theory.

  2. Alamanach says:

    The one thing that always seems to get overlooked when people start going on about the Drake Equation is that little bit about intelligent life developing technology. People look at the technology that humans have developed, and assume it is a normal thing to do. But our technology, even by our own human standards, is anything but normal. To develop technology the way we have is a radical departure from how humans normally behave.

    I say this because if you look back at all of humanity’s cultures, only one developed the modes of thinking that would eventually allow for the development of modern science and engineering. No other culture comes close. It was the ancient Greeks, with their peculiar methods of abstract, rational thought that laid the groundwork for the rocketships, computers, and radio telescopes that came later. That kind of rationalism isn’t a natural development, it is freakishly weird.

    In any other culture, people didn’t think about a problem objectively or formally: they thought about it subjectively, they thought about it in terms of how it applied to them. Some limited math and technology could still develop; the Egyptians, Indians, and Chinese did all right. But even in those cultures there was not the idea of an objective reality that exists independent from people’s opinions about it. In those cultures, there was a king, and life was oriented around the king, and things like math and science had truth and utility only insofar as they related to king and to society. These were subjective cultures, created by subjective, emotional, self-centered people. All cultures except one have been of this sort, because this subjective kind of culture is the norm.

    Had the Greeks been defeated at Salamis, there is no reason to think that their unusual worldview would ever have appeared again. I am at a loss to explain how it ever appeared the first time. If such a culture is so rare for us, why should we expect it of others?

    • bruceleeeowe says:

      I say this because if you look back at all of humanity’s cultures, only one developed the modes of thinking that would eventually allow for the development of modern science and engineering. No other culture comes close. It was the ancient Greeks, with their peculiar methods of abstract, rational thought that laid the groundwork for the rocketships, computers, and radio telescopes that came later.

      There were many civilizations which were advanced enough than ancient greeks like Ancient Indians and others. Due to some reasons it collapsed later.

      If such a culture is so rare for us, why should we expect it of others?

      because it’s possible that there are many.
      bruceleeeowe.

  3. Alamanach says:

    “There were many civilizations which were advanced enough than ancient greeks like Ancient Indians and others. Due to some reasons it collapsed later.”

    Sure, the Egyptians, for example. Pharaohnic culture lasted 3,000 years. Recorded history is only about 5,000 years old, so for more than half the time that history has been going on, the pharaohs have been ruling Egypt. Their fall was, in some respects, the biggest news story in human history.

    I point them out because the Egyptians, obviously, were plenty advanced. Their longevity as a culture, though, indicates that their failure to develop modern technology had nothing to do with their collapse. Given more time than anybody, and ample wealth, sophistication, and social stability, they still failed to develop modern science or engineering. Why? Not because of collapse, but because of mindset. The Egyptians never viewed their world in a way that would permit them to develop modern technology. Virtually no culture does.

    I’m not trying to suggest that the Greeks were more advanced than their neighbors, just that their way of thinking was significantly different. That different way of thinking, later and as applied by others, would give us the modern world. Because the Greeks were such an oddity in human history, I think we have to assume that most societies of intelligent beings will tend to form cultures more like the Egyptians, the Indians, the Chinese, etc: static, stable, and with a level of technology that has a definite plateau. Someone would have to show me why the Greek phenomenon was ~not~ unusual before I could be persuaded to believe that we should expect it to occur elsewhere.

  4. bruceleeeowe says:

    I’m not trying to suggest that the Greeks were more advanced than their neighbors, just that their way of thinking was significantly different. That different way of thinking, later and as applied by others, would give us the modern world. Because the Greeks were such an oddity in human history, I think we have to assume that most societies of intelligent beings will tend to form cultures more like the Egyptians, the Indians, the Chinese, etc: static, stable, and with a level of technology that has a definite plateau. Someone would have to show me why the Greek phenomenon was ~not~ unusual before I could be persuaded to believe that we should expect it to occur elsewhere.

    That started just two or three century ago only. So your arguments proved to incorrect.

  5. Pingback: Fate of Our Civilization and Tactics « WeirdSciences

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