I wrote this essay after reading (and commenting upon) John Michael Greer’s essay on the Fermi Paradox (“Solving Fermi’s paradox”) on his website at: http://thearchdruidreport.blogspot.com/. Readers might want to check it out. He reaches a conclusion which overlaps substantially with mine, but which also differs significantly as well.
Peak Oil and the Fermi Paradox
Talking about the likelihood of other civilizations existing in our galaxy, physicist Enrico Fermi reportedly asked in 1950: “Where is everybody?” This question became known as the Fermi Paradox. The Paradox arises because there should be at least a few other civilizations in our galaxy of 400 billion suns.
In 1960, Dr. Frank Drake, created the Drake equation (see discussion at: http://en.wikipedia.org/wiki/Drake_equation ), which indicated that there ought to be at least 10 other civilizations in our galaxy right now. Yet we can find no evidence for their existence.
Which takes us back to Fermi’s question: “Where is everybody?”If other civilizations exist, then it would seem reasonable that at least some would be more advanced than ours, and would presumably be able to travel to nearby star systems. After a few millions of years they ought to have colonized the entire Milky Way Galaxy. Radio astronomers have been searching ever since Frank Drake undertook the first scientific search for extraterrestrial civilizations with Project Ozma back in 1960. Yet there is no sign of extraterrestrial civilization anywhere in our galaxy. The silence across the galaxy has been deafening. So where are they?!
I think that the actual answer to the Fermi Paradox lies in the fact that while life itself is likely very common throughout the universe, the conditions needed for intelligent life--basically environmental stability for geological ages--are hugely improbable. Thus intelligent life is very, very, rare.
This theme is developed in great detail in the book Rare Earth: Why Complex Life is Uncommon in the Universe, by Peter Ward and Donald Brownlee, two University of Washington astrophysicists. In my new book, which will be published late this year (2007) The Path Through Infinity's Rainbow: A Guide to Survival, Transformation and Renewal, I discuss this idea:
Location, Location, Location: The Earth As Prime Real Estate in the Universe If the sun were more massive than it is, it would have exploded into a nova and then burned out into an ever cooling white dwarf star by now—not allowing enough time for a species such as humanity to develop. If it were smaller and dimmer, its habitable zone, where water remains liquid would be much smaller. Thus, the chances that a planet would form at just the right distance from the sun within this narrow habitable zone would be much reduced. This problem of remaining within the star’s habitable zone would be compounded because all stars heat up as they age. This means that the time that any planet could remain within a dimmer sun’s habitable zone would be far briefer than the four-plus billion years required for an intelligent species to evolve on Earth. Our sun has proved to be just bright enough to allow us this immense period of time for our evolution.
Our Earth’s placement within the habitable zone has also proved optimal. Consider Venus with its hellish runaway greenhouse atmosphere, and frigid Mars as examples of not-quite-right placement. Mars’ thin atmosphere and lack of plate tectonics also demonstrates what a not-quite-right size has on the chances for complex life to evolve.
Additionally, Earth orbits around the center of our Milky Way galaxy in a 226 million year long orbit. This orbit fortuitously keeps us far away from the dangerously radioactive core of our galaxy and outside of the galaxy’s supernova producing spiral arms. Our solar system possesses a galactic orbit that accommodates the needs of carbon based life such as we are. Also, Earth possesses a large satellite—our moon. This keeps the Earth gravitationally stable so that it does not tilt erratically on its axis, which would cause unending climatic chaos. Additionally the planet possesses a molten core that drives plate tectonics which seems to be critical for life to evolve in complexity.
I go on to look at the necessity of plate tectonics if complex life is to evolve. Here's a quote from Rare Earth, which I excerpt in The Path Through Infinity's Rainbow.
First, plate tectonics promotes high levels of global biodiversity. In the last chapter we suggested that major defense against mass extinctions is high biodiversity. Here we argue that the factor on Earth that is most critical to maintaining diversity through time is plate tectonics. Second, plate tectonics provides our planet’s global thermostat by recycling chemicals crucial to keeping the volume of carbon dioxide in our atmosphere relatively uniform, and thus it has been the single most important mechanism enabling liquid water to remain on Earth’s surface for more than 4 billion years. Third, plate tectonics is the dominant force that causes changes in sea level, which, it turns out, are vital to the formation of minerals that keep the global level of carbon dioxide (and hence global temperature) in check. Fourth, plate tectonics created the continents on planet earth. Without plate tectonics Earth might look much as it did during the first billion and a half years of its existence: a watery world, with only isolated volcanic islands dotting its surface. Or, it might look even more inimical to life; without continents, we might by now have lost the most important ingredient for life, water, and in so doing come to resemble Venus. Finally plate tectonics makes possible one of Earth’s most potent defense systems: its magnetic field. Without our magnetic field Earth and its cargo of life would be bombarded by a potentially lethal influx of cosmic radiation, and solar wind “sputtering” (in which particles from the sun hit the upper atmosphere with high energy) might slowly eat away the atmosphere, as it has on Mars.
For those cosmically rare occurrences where an intelligent species does evolve, it is likely that some will never develop an agricultural civilization, much less industrial technology based upon hydrocarbons, before they become extinct. After all most of humanity's 100,000 thousand year history was spent as hunter-gatherers.
Agriculture only took root (so to speak) about 10,000 years ago. During the long millennia when humanity was a hunter gatherer species confined to Africa, the volcanic eruption at Toba 70,000 years ago nearly finished ALL of our ancestors off. (See http://en.wikipedia.org/wiki/Toba_catastrophe_theory for details. Also check out a new book on this very topic by my friend Marie Jones entitled Supervolcano: The Catastrophic Event that Changed the Course of Human History.)
However, assuming an intelligent species survives until it develops an industrial technology, there is only a very short window of opportunity for an emergent planetary civilization to bootstrap itself into the solar system. Again quoting from The Path Through Infinity's Rainbow:
It is important to understand that only a high energy, high technology; civilization is capable of bootstrapping itself into the solar system. There it can harness the vast resources of raw materials and energy found in the asteroid belt, the Kuiper Belt, and the Oort Cloud, the atmospheres of the gas giants—hydrogen in particular—and the endless supply of energetic sunlight which radiates outward ceaselessly, from our sun.