Where is everybody?

Everyone so often, I come across an interesting article or hear about something that I want to write about, even if the article or bit of information has nothing to do with leadership.  As my father has always told me, it's good to be well-rounded and knowledgeable about a lot of different things.  With my father's sage advice firmly in mind, I wanted to explore a recent article I came across that involves the Drake Equation, the Fermi Paradox, and something called the Great Filter.  It's all in the spirit of being well-rounded!

I first heard about the so-called Drake Equation on Carl Sagan's 1980 television mini-series "Cosmos" (I remember getting the book that Sagan wrote as a companion to the mini-series that year for Christmas).  Frank Drake developed the equation bearing his name in 1961 to "estimate" the number of extraterrestrial civilizations that could theoretically exist in our Milky Way Galaxy.  Contrary to popular belief, the equation is more conceptual than numerical (in other words, the equation doesn't actually estimate the number of extraterrestrial lifeforms) and has been used to try to answer the questions "Is there life out there?" or "Are we alone?"  Here is the equation as originally formulated by Dr. Drake:

N = R* x fp x ne x f1 x fi x fc x L

where, 

N is the number of civilizations with which humans could communicate

R* is the rate of new star formation in the galaxy

fp is the fraction of those stars that have planets (like our solar system)

ne is the number of planets that could support life per star with planets

f1 is the fraction of life-supporting planets that actually develop life

fi is the fraction of planets with life where life develops intelligence

fc is the fraction of intelligent civilizations that develop technology to communicate with us

L is the length of time that civilizations can communicate

Again, the Drake Equation was never intended to actually come up with a quantifiable number of civilizations that which we could possibly communicate with, though several experts have provided estimates for each of these variables.  Drake originally estimated that N closely approximated L and concluded that there were probably between 1,000 and 100,000,000 planets with civilizations in the Milky Way Galaxy.  If that is indeed the case, then why haven't we been able to communicate with at least one of these civilizations?  

The great 20th century Italian physicist Enrico Fermi asked this very same question in the 1950's.  As the story goes, Fermi had a casual conversation in the summer of 1950 with fellow physicists Edward Teller, Herbert York, and Emil Konopinski in response to several reports of UFO sightings in the media.  While the exact quote is not known, Fermi is said to have blurted out, "But where is everybody?"  In other words, if there is intelligent life out there, why haven't we been able to communicate with them?  If, as revealed by the Drake Equation, that there are anywhere between 1,000 to 100,000,000 planets with civilizations in our own galaxy, why haven't we been able to contact them?  This, in essence, summarizes the Fermi Paradox.  

Here is where the article that I found comes in.  Scientists at NASA recently submitted a manuscript for publication that provides a possible explanation to the Fermi Paradox.  The manuscript has not been peer-reviewed (meaning that it hasn't been accepted for publication yet).  These scientists talk about something known as the Great Filter.  Robin Hanson, an economist at George Mason University argued in an essay he wrote in 1996 ("The Great Filter - Are We Almost Past It?") that our failure to locate extra-terrestrial life is due to some impenetrable barrier (or filter) that prevents intelligent life from developing to the point where it can communicate with us.  Hanson states that there are nine steps along the evolutionary path to intelligent life:

1. The right star system (potentially habitable planets that can support life - see the Drake Equation above)

2. Reproductive molecules (RNA, DNA, etc)

3. Simple (prokaryotic) single-cell life

4. Complex (eukaryotic) single-cell life

5. Sexual reproduction

6. Multi-cell life 

7. Tool-using animals with intelligence

8. A civilization advancing toward the potential for a colonization explosion

9. Colonization explosion (specifically, space colonization)

Hanson pointed out that life on planet Earth has made it successfully from step 1 through step 8, though we have yet to progress to the 9th and final step (so perhaps this is the ultimate barrier to finding out if life exists elsewhere).  He further argues that because we have yet to find evidence of extraterrestrial life, progression through these steps is very improbable, suggesting that there is a "Great Filter" along the path from the primordial soup to colonization.  He wrote then that "the fact that our universe seems basically dead suggests that it is very very hard for advanced, explosive, lasting life to arise."

Hanson also suggests the possibility of some sort of catastrophic social collapse, such as what happened to the dinosaurs here on planet Earth that effectively wipes out life's progression from steps 1-9.  Alternatively, intelligent life tends to destroy themselves before being able to make contact off-planet.  To that end, a group of investigators from NASA's Jet Propulsion Laboratory proposed several different ways that life on planet Earth could be wiped out, including nuclear war, pandemics, asteroid or comet impacts, climate change, and artificial intelligence.  I would argue that it doesn't take a creative genius to come up with a list of possible scenarios ending life as we know it, just watch any of a number of popular science fiction movies involving these apocalyptic scenarios.

There is one last possibility for why we haven't found evidence of intelligent extraterrestrial life (see my post "Weird Science" for a more detailed explanation).  Basically, this one comes straight from the science fiction movie "The Matrix" .  The Oxford philosopher Nick Bostrom proposed a few years ago  that at least one of the following statements is true - (1) the human species will become extinct before we progress to a post-human state (think artificial intelligence, virtual reality, robotics, and cyborgs!); (2) any post-human civilization is unlikely to actually run a computer simulation of real-world life and humans (basically because they either don't possess the ability or they are too ethical to do so); or (3) we are already living in a simulated world (which is to say that we all co-exist in the Matrix).  If we are living in a simulated world, then of course we wouldn't find evidence of life in outer space.  But then again, why wouldn't we?

All of this is very interesting to ponder.  And perhaps the takeaway lesson here is that we need to be careful about what we are doing to our planet.  It may be the only planet that we will ever have, and we need to be careful about not being the cause of our own destruction.