At one time I thought God created everything, but I can’t remember ever truly believing it was during 6 very busy days. I do remember giving serious consideration to whether or not Purgatory would be an interesting place to stop before going to Heaven, even if there was a small chance I could be sent instead to Hell by mistake. Then soon after I seriously began studying science, I put my inner religious beliefs into a little box and went on, unencumbered, to feed my curiosity. I didn’t throw my beliefs away. I believe that as you go through life, you should try not to throw things away unless you really need to. We already lose too much as we grow older.
I learned that it’s likely life emerged from non-life by a trick of chemistry, and that was that. I had bigger fish to fry – how the Earth and other planets formed. I knew scientists didn’t really know exactly how life began, but I figured they would find out soon enough. It wasn’t for me an important question for a long time.
(An aside: I sometimes wonder whether I would have become obsessed with life’s origins, had I went further in the direction I explored my senior year in college. I was good at chemistry in college, and I took a class called Thermodynamic Geochemistry, which sounds a lot tougher than it actually was – but it would have gotten very tough if I had pursued it.)
Meanwhile, for the scientists who work on it, the origin of life has been an unusually thorny problem. There have been many side-tracks along the way, from primordial soup to deep sea vents to extra-terrestrial origins (panspermia).
The State of Our Knowledge of Life’s Origin
We don’t really know what kind of environment hosted the first life. It could have been in a thermal area, or in ice, or even in solid rock. It could have been on Mars. But wherever it was, water very likely was the dominant substance surrounding the primitive beings.
Perhaps a non-living compound underwent some chemical transformation into RNA. RNA can do the work of forming proteins (as it’s doing right now inside you) but it can also reproduce, like DNA. Then it’s just a matter of finding itself in the right place at the right time (pre-cells), to be put to work in an entirely novel way in something we would now call alive.
Or perhaps non-living structures similar to our body’s cells first started to form in high-energy environments (like deep sea vents) and they began to process energy (it’s thermodynamically favorable). Then they began to reproduce (via RNA). Most scientists believe that RNA is an important key.
Perhaps you know of Craig Venter. He’s the guy who led the team who first decoded the human genome. He’s at work now on trying to create a living organism with no biological parents (actually a computer takes the parents’ place). Many believe that creating life ourselves is necessary before we can understand how it arose. As Richard Feynman once said, “What I cannot create, I do not understand”.
You can see there is some uncertainty here, and every good chemist knows these transformations are not at all easy. But it happened. Stuff happens after all, and given a lot of time and the right environment, perhaps life has been emerging everywhere, throughout the history of the universe. So what if we can’t explain the moment of life’s creation. Does it matter?
I tend to think that life in this solar system evolved on Earth first, but I wouldn’t bee too surprised if it started on Mars first and was transported to Earth riding on a meteor. I also believe that this question: how did life start, is an important one. I think it will take us a big step forward in figuring out how life emerged in the universe. How we got here is one thing, but it will take much more insight to discover why we are here.
This story will continue, so stay tuned…