Well this site is about Life, the Universe and Everything, so where better to bring this up?
I am just starting to read Carl Sagan’s “The varieties of scientific experience” and just in the first few pages it had me revisiting this old problem of mine.
Life as we know it, in all its forms is based on DNA – on this planet at least. Life as we see it all around us has been undergoing evolution ever since it kicked off – I’m very happy with that. What I was (and still am) very unhappy about is the apparent lack of DNA precursors. DNA is a pretty complex molecule, are we meant to believe it just suddenly arrived, completely built and ready to go? There is an analogy often made about this regarding a hurricane going through a metal scrap yard and creating a pocket watch – but the probabilities of course are much lower than this. So, my initial naive way of thinking went like this, there must have been simpler DNA precursors which themselves underwent evolution to give us the DNA we see today. Problem is, we don’t see any evidence of these precursors and we don’t see any life on this planet based on anything other than DNA. I actually knew the answer to this one but still came up with the stupid idea anyway. What is the answer? The answer is, it’s DNA all the way back, right back to the beginning – the first forms of life on Earth were based on the same DNA structure, so there were no precursors, like turtles, it’s DNA all the way down.
Now I really do have a problem, but I also have a solution to the Fermi problem. My problem is this. What is the likelihood/probability of the DNA molecule coming together like that something like 4 billion years ago? The observer’s answer is that is must be finite ‘cos here we are. Finite yes, but how small a finite are we talking here? 10^-20? 10^-100? 10^ -Googol??
I have been heard to say on television (Chris Packham’s Inside Out BBC programme) that there is “life out there” – that the Universe is teeming with life. I would like to change that one slightly in the view of this DNA business. I don’t think there’s any life out there beyond this planet, none at all. Nothing based on elements other than Carbon or molecules other than DNA – nothing. There’s your answer to the Fermi problem. We haven’t heard from them yet because there’s nobody out there calling.
This does create a rather important corollary. We should be just a little more considerate and caring not only of each other, but all the creatures on this planet – and of course the planet itself. Stupid boys with idiot haircuts spouting nonsense intended to upset the other people on this planet are not helping things along much. It really is time to grow up – fast.