2023-09-20 15:45:42
Life on a distant planet will surely be very different from that on Earth. But it will necessarily share some basic foundations with life on our world because the number of chemicals suitable as ingredients for life and the number of ways suitable for combining them are finite and in fact quite limited. Taking this into account, scientists have compiled a catalog with all the chemical combinations capable of satisfying an essential requirement for the emergence of life.
As Betül Kaçar, an astrobiologist at the University of Wisconsin-Madison in the United States and co-author of the new study, argues, the emergence of life is a process that goes from less to more. Progressing from basic chemical ingredients to the complex cycles of cellular metabolism and reproduction that define life requires not only a simple beginning leading to ever greater complexity, but also that that beginning be repeated over and over again. This increase in complexity cannot depend on a one-time coincidence. The conditions that lead to life must be repeated. And the clearest way to do this is through chemical reactions that produce molecules that allow the same reaction to be repeated over and over again. Reactions of this kind are called autocatalytic. Therefore, it seems evident that the chemical reactions to firmly initiate life on a world must be autocatalytic.
In their new study, Kaçar’s team, Zhen Peng of the University of Wisconsin-Madison and their colleagues collected 270 combinations of molecules (with atoms from all groups and series of the periodic table) with good potential for sustained autocatalysis.
“These types of reactions were thought to be very rare,” explains Kaçar. “We’re showing that they’re actually not rare at all. You just have to look in the right place.”
Life requires the repetition of chemical reactions. A good knowledge of the types of reactions and conditions necessary for self-sustained repetition (autocatalysis) will help search for life on other planets. (Illustration: Betül Kaçar)
Chemical reactions of the type described give rise to multiple copies of some of the molecules involved, providing materials for the next steps of autocatalysis.
Autocatalysis is like a growing population of rabbits. They mate, produce litters of new rabbits, and then the new rabbits grow and mate, producing more rabbits, and so on. It doesn’t take many rabbits for there to soon be a large population of them.
The study is titled “Assessment of Stoichiometric Autocatalysis across Element Groups.” And it has been published in the academic journal Journal of the American Chemical Society. (Source: NCYT from Amazings)
#Chemical #combinations #appearance #life #worlds