Complex Molecules in Space
A few months ago I attended a day-long workshop about the chemical origins of life. The talks were aimed at tracing the chemicals that make up our very basic units (RNA, DNA) from first principles to the garden of biologic diversity we inhabit today. One of the talks focused on the finding the chemical precursors of life in interstellar dust clouds, which is really kind of a mind-blowing concept. But, when you think about it, since everything is chemical in origin, it makes sense that some of the chemicals that existed in the cloud our solar system formed in would also play a part in the origin of life.
There are organic molecules everywhere in space (and obviously here on Earth, but also at Jupiter, Saturn, and Titan. Researchers at Imperial College in London (England) have identified xantine and uracil — two very complex molecules needed to form RNA and DNA — in fragments of a meteorite that landed in Australia. The molecules didn’t come from Earth; they were present in whatever place the meteorite first formed. Which means that those molecules existed when the solar system formed, some 4.5 billion years ago. Eventually, rocks containing those molecules landed on Earth. It’s not much of a leap of the imagination to see that the ingredients for life could well have been delivered from space, and that we are really and truly “space stuff.”
What this should tell you is that the search for life in the universe isn’t really a search for little green men or cosmic omnisciences. It’s a journey that organic chemistry will lead, and all we have to do is study what it gives us.