The search for life outside our tiny blue rock has consumed the imagination of man for decades. But now, with increasingly advanced technology we may finally be on the verge of discovering where else life may exist in our galaxy. The more we search, however, the more we realize that life may be rather precious after all.
There have already been claims of detection, mostly met with controversy for one reason or another. And accompanying said claims comes the unfounded declarations that life must also exist on these worlds.
But just because we find a planet that appears fit for life, and I am sure that we will in the not too distant future make such a discovery, does it mean necessarily that life does exist there?
Well, no. A major sticking point to discussions of life on other worlds is the question of how life originates in the first place. We see life all around us, and thus often take its existence for granted.
How Life is Made
We often point to the fact that we can "manufacture" cells in a laboratory, so how hard could it really be for life to spring up in the right conditions? The problem is that even when we "create" cells, we are not actually building them from the raw materials. Rather we are taking already living cells and replicating them through one of several means.
I am neither an organic chemist, a geneticist, a zoologist or anything akin to these. My background is in astrophysics, so I am not truly qualified to speak to the specifics, but I having spoken with such experts have drawn a couple basic conclusions that even I can understand.
- It's not as simple as people seem to think. I am continually astonished at the number of people that believe that mankind possesses the ability to create life from nothing. The fact of the matter is that even being handed all the needed components, and assembling them in ideal conditions, we can't make even one living cell from scratch. It may very well be possible someday, but we're not there yet.
- We don't really know how the first living cells formed. Sure we have some ideas, but as stated in the previous point, we can't replicate the process in a lab. Even in ideal conditions. So we don't really know where they came from.
Right. So we don't really know how life is made. And we don't know where life comes from. Of course religious types will argue that the answer is that God created the first life. While others stand on the side that, sure it may be difficult, but given enough time, enough thermal energy, enough mixing of raw materials in the oceans and you are bound to accidently produce life.
From there you just have to get lucky and hope life, over the subsequent billion years, is able to struggle against all odds to eventually form complex beings capable of intelligent thought.
Fair enough. Humans are living proof that by one means or another it is possible for life to form. So it should follow that in the vastness of the galaxy there should exist another world with conditions for life to exist and upon that tiny orb life would have sprung up. Right? Well, not so fast.
How Rare is Life in our Galaxy?
Attempting to estimate the number of life forms in our galaxy is a bit like guessing the number of words in a book, without being told which book. Since there is a large disparity between, for instance, Goodnight Moon and Ulysses, it is safe to say that you don't have enough information.
Equations that claim to do exactly this are met with staunch criticism, and rightfully so. On such equation is the Drake Equation.
A conglomeration of variables that we couldn't possibly know reasonable values for, the Drake Equation is a fun little calculation to do, but ultimately it is useless. Depending on your particular guesses for the various constants, and your values are probably just as probable as anyone else's, you could get a value much much less than one (meaning that we are almost certainly alone) or you could arrive at a number in the tens of thousands.
So, where does this leave us? With a very simple, yet unsatisfying conclusion. Could life exist elsewhere in our galaxy? Absolutely. Are we certain of it? Not even close.
Unfortunately, until we actually make contact with a people not of this world, or at least begin to fully understand how life came to exist on this tiny blue rock, that question will be answered with uncertainty and estimation.
In closing this missive, I put to you one final thought; a phenomenon known as the Fermi Paradox posits: If life is so common that it should spring up on any world where the conditions are right, and this life eventually evolves into beings capable of technological development, why then have we never been contacted by any such race of beings? We've certainly been listening.