Tuesday, October 19, 2010

The Search for Intelligent Life

The title of this article does not mean to imply that humans are not intelligent.  It refers to the ongoing search in the Universe for intelligent life other than human beings, and some other animals here on Earth.  I should point out that humans have proven themselves to be unintelligent on many occasions.  One of the best comic strips I have ever seen has two aliens discussing the homo-sapiens they recently discovered on this planet called Earth.  One says to the other: “The Earthlings have placed weapons of mass destruction in orbit around their planet”.  To which the second alien asks, “An emerging intelligence?”  The first alien responds, “They have the weapons ... pointed at ... themselves.”  The two aliens then stare at each other in a very confused state.  Frankly, given the frequency with which our species attacks itself, it is amazing we’ve made it this far; but that is the subject for another article.
As of late, there have been an increased number of UFO sightings.  I am skeptical of these for many reasons.  From my point of view, these light shows in the sky have been planted by groups of people as a hoax, similar to the teams of attention-seekers who have been making crop circles in the backyards of defenseless farmers for decades.  With improved technology, these folks have taken their shows to the skies.

I would like to put these people, whose aim it is to mislead the public, aside, but still focus on one of the most interesting questions man has ever posed: “Are there such a thing as aliens?”  This question is, however, poorly worded.  I would like to investigate two questions: (1) does intelligent life currently exist somewhere else in the Universe, and (2) will we ever encounter them?
The first question has been investigated in great detail by Dr. Frank Donald Drake.  Born in 1930, the American Astronomer and Astrophysicist is most famous for developing the Drake equation.  The Drake equation predicts the number of communicative civilizations that co-exist in the Universe at a given time.  If we say that for life to be deemed intelligent, it must have the ability to communicate, then the Drake equation should yield the answer to our first question.  Unfortunately, large assumptions must be made in order to solve the Drake equation.  Therefore, there is an enormous amount of uncertainty in this number.  Drake himself calculated that there were about 10,000 communicative civilizations co-existing in 1995.  More sobering views have determined that this number is closer to two or three, including us.  Either way, it would seem that the answer to our question number one is “yes”.
Professor Andrew Watson, a scientist from the University of East Anglia in the UK, has investigated the likelihood for life to develop on a habitable planet such as Earth.  Watson determined that the chances of intelligent life to evolve on a planet such as Earth within 4 billion years or less are 1 in 10,000.  Four billion years is the amount of time that it actually took for man to evolve here (the Earth formed about that long ago); according to Watson, this evolution into a communicative civilization was the result of four extremely unlikely events.  Planet Earth will only be habitable for a maximum of one billion more years, as the Sun will be burning hydrogen at a significantly higher rate by that time (water on Earth will no longer be in a liquid state).  That means that man came into being in the late stages of the Earth’s habitation period – man’s evolution took roughly 80% of this five-billion-year period.  In summary, there may be a huge number of habitable planets in existence, but intelligent life is unlikely to evolve on the vast majority of them.  What’s more, once intelligent life pops up on a given planet, the habitation period on that planet will likely be nearing its end, in a relative sense.
Mankind is unlikely to survive for another billion years.  Our species risks extinction within tens of thousands of years unless it finds another planet to inhabit within that timeframe.  Life on Earth will certainly survive much longer than that, but man’s physical limitations could be exacerbated by the changes to our biosphere that have already begun to take place.  To say man will survive another hundred thousand years would be a realistic prediction.  If that were to occur, man would have survived for 0.002% of the habitation period of the planet it evolved on.  This means that not only does intelligent life take a very long time to evolve, but its appearance in the Universe is a relatively brief one.  These kinds of observations enter into the Drake equation, and tell us that there are a finite number of communicative civilizations in the Universe at a given time.  That finite number is probably more than one.
So, while we are probably not alone in the Universe, will we ever receive certain proof to that effect?  The answer to this question is “probably not”.  The Universe is a very big place.  Even if several hundred communicative civilizations currently exist, their planet of origin is likely located hundreds of light years away, if not thousands, if not more.  By the time the light from one of those civilizations reaches us, the intelligent life it reveals may be extinct.  Still, such a discovery would give certain proof of other intelligent life.  If we assumed that the civilization were still alive and well in real time, it would take us hundreds or thousands of years for us to travel to them if we were able to travel near the speed of light - a feat we may never be able to reach.  If such a voyage were possible, it would not age the passengers all that much.  If the ship were travelling just under the speed of light, and their destination were 100 light years away, the space travellers could arrive having only aged by, say, one year (as predicted by our fellow Earthling, Albert Einstein).  The civilization that was being visited would still age by a century during the trip.
Even though a close encounter with an alien species is extremely unlikely to ever occur, it is not impossible.  Some suggest that indeed other life forms have walked the Earth, but have not revealed themselves (think cloaking device).  It is possible that there are other life forms out there that are much more technologically advanced than homo-sapiens, and have decided to conceal their identity or pose as one of us (think Keith Richards).
It is fun to dream of such things.  However unlikely it would be to meet an alien species, imagine for a moment the impact that such an event would have on our daily lives.  Without question, our knowledge of the world would change drastically.  All laws of science as we know them would likely need revision – just when I was beginning to understand general relativity!  What questions would you ask an alien visitor?  Indeed, contact with another intelligent life form is the basis for some of the best works of science fiction.  Personally, I would welcome such an occurrence.  Perhaps an event of this magnitude would cause us to smarten up, to reach our potential.  Who knows, we might even stop attacking our own species for a while.

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