Weekend assignment

There are those who believe that life here began out there...

   One of the offshoots of having a blog with almost 350 entries in it (yes, I hear you old-timers calling me a pup) is being unable to remember if I have previously written about a specific topic. Thanks to Journals Editor Joe's expertise, a quick search revealed that this particular topic, which I was almost certain I had written about, is still open.
   Thursday's press release from NASA regarding the suspected presence of liquid water on the Saturnian moon Enceladus has revived Internet discussion of the possibility of extraterrestrial life, and prompted John's latest weekend assignment:

Weekend Assignment #102: Do you honestly think there is life out there in the universe? And if so, what kind of life do you think it is?

Extra Credit: Name your favorite (fictional) alien creature.

   In answer to the first question, I would have to say, "yes, of course." Answering the second is stickier. Life has a pretty wide definition. The African Violets on my kitchen windowsill? Life. The piece of fungus stuck to the underside of the fallen tree in the forest? Life. The green pond scum coating the surface of the watering hole in the dog park? Life. The little particles of bacteria floating around in the air after your kid coughs without covering his mouth? Life. Somewhere else in the universe, maybe even in our own solar system, basic life exists.
   But, that isn't the kind of life we all think about when we ask ourselves John's question, is it? No. We are talking about life like ourselves; life that creates and manipulates technology; life that communicates over long distances using that technology; life with which we might, one day, converse.
   The kind of life that Astronomer Frank Drake called a "technologically communicative civilisation." In 1961, Drake, in a thought experiment designed to encourage further speculation on the possibilityof the existence of extraterrestrial civilisations, formulated what has become known as 'The Drake Equation.' The Drake equation was an attempt to estimate the likelihood of other technologically advanced societies being 'out there.'
   I learned a version of the Drake equation in Astronomy101, the university science course all arts majors chose to fulfil their "breadth requirement" and receive a well rounded education. I say 'a version' of it because a bit of googling has revealed that it is commonly stated in several similar, but not identical forms. I find that odd, considering the guy is still alive and working, and can certainly vouch for the way he originally stated it. The version of it I learned resembled (to the best of my memory) this: N=N*(fp)(fe)(fl)(fi)(fc)(L). The terms were defined as follows:

N - The number of technologically communicative civilisations on the galaxy. Why technologically communicative? Well, Frank Drake was one of the founding members of an organisation called SETI (the Search for Extra Terrestrial Intelligence). The only way for us to determine if there is another enclave of intelligent life out there is if they are communicating, and we manage to overhear them. They have to be using some form of technology for that to happen.

N* - The number of stars in our Galaxy.
fp - The fraction of those stars that develop planetary systems.
fe - The fraction of those planetary systems that have one or more planets at an appropriate distance from their sun. Too close is too hot, and too far away is too cold.
fl - The fraction of those 'earthlike' planets upon which life (of any description) forms.
fi - The fraction of life bearing planets upon which that life develops intelligence.
fc - The fraction of those intelligent societies that develop both the means and the desire to communicate over interstellar distances.
L - The average lifespan of a technologically communicative society.

   That last one is the kicker, of course. For all the others, numbers can be plugged in based on one estimation or another. The last number defies description. Our society can be said to have been technologically communicative since about 1957, when the first communications satellites were launched. So, we are going on fifty years. How much longer will our civilisation last? Who knows? Although estimates are certainly more positive now than they were back in the eighties, when we were all convinced that Ronald Regan was looking for any excuse to "press the button."
   In my first year university astronomy class, our professor suggested a set of values for the variables in the Drake equation that led to N=L. That is, all the other variables multiplied out to 1, which made the number of civilisations in our galaxy equal to our estimate for the average lifespan for said civilisations.
   Other estimates to be seen around the web range from less than one, to several thousand, and there is much discussion and disagreement surrounding the various values used for each term in the equation. Which, of course, was Drake's intent all along. He had no illusions that there was some right answer to the question. He just wanted to prompt discussion. Smart guy.

   When a significant amount of that discussion resulted in solutions for the Drake Equation that were significantly greater than one, a physicist by the name of Enrico Fermi decided to pitch in his two cents. If, he postulated, there are, indeed, dozens, hundreds, perhaps thousands of these advanced extraterrestrial civilisations, then where are they? We theorize that there are many, yet we have discovered evidence of none. This is what is known as the Fermi paradox.
   It's a good question. If there are all these aliens out there, why haven't we found them, or they found us? Let's just leave aside all those wackos who insist they have found us, and are currently studying us via probes to Uranus, if you know what I mean (Real mature, Bradley).
   There are a number of potential answers to that question. My favourite one is the laws of physics barrier explanation. It goes like this: The interstellar distances necessary to cover in order to visit other star systems are so great that, given our current understanding of the physical universe, journeying to even our closest stellar neighbour could not be done in time frames measured in less than centuries.
   So, do I think there is life somewhere, out there? Yeah, I do. Do I think we will ever meet them? No, I don't. At least not within the next several thousand years.

   Oh, and that extra credit question? Gotta be Klingon. Coolest aliens ever invented. EVAR!!1


"Sir, I protest. I am not a merry man!"

tags:Weekend Assignment,Science,Memes