Question: In your opinion, what is the most interesting enigma of modern science, and what do you think the explanation will be?

Jon Copley answered on 16 Jun 2010:

Nice question… For me, probably the most interesting unanswered question in science is “how did life on Earth begin?”.

Life on Earth has transformed our planet from a barren rock into a world that is very different to the others we have found so far. If we can understand how life began, then it will help our search for life beyond Earth – and “are we alone / is our living world unique” would be a HUGE question to answer, perhaps making a lot of people rethink their view of the world. By “are we alone”, I don’t mean intelligent extraterrestrial life (though of course that would be staggering), but even just life analagous to Earthly microbes.

I think we’re getting closer to cracking how life on Earth began, but there are still huge challenges to figuring out something that happened probably around four billion years ago, when conditions on Earth were very different to those today. I like to think of it as a crime scene – but much of the evidence has since been washed away, eroded, obliterated, or generally tampered with now that modern life leaves its own “fingerprints” smeared everywhere.

If I had a definitive answer, then I’d have a Nobel Prize (and there’s also a separate prize specifically for anyone who solves the origins of life, not that science is about chasing prizes). There are two approaches to the problem. One is to look at all modern living things, and by identifying the similarities between them and comparing the differences, figure out what their “universal ancestor” must have been like. But that approach has run into some big roadblocks (because the way that microbes pass on genetic material can be different to that of other organisms – genes can “jump” between different types of microbes that are not actually related).

The other approach is to think about what you need to build life from scratch, and see how and where that could happen. There have been lots of advances in making the “building blocks” for life, in lots of different ways (but that’s still a very, very long way from actually putting together a living organism). One environment that looks promising for that are the kinds of undersea volcanic vents where I work. But they’re far from the only candidates – there are lots of other places where you can do neat “prebiotic” chemistry with the building blocks for life, such as in clouds, shallow ponds, or even dust in space.

So it’s going to take a lot more work, I think… Maybe one of you could be the one to solve it? In the meantime, if you are interested (or bored!), here’s a link to a video of a lecture that I give to first-year university students about the origins of life. Some of the content is actually is a little out-of-date now (it was recorded a few years ago), but I think it’s still ok for an introduction to the subject. The file is pretty large (11 megabytes), so it may take a few minutes to download:

http://www.thesearethevoyages.net/ias/origins.html