Abstract

We will present two different ways of investigating the origins of life. We will looks at the conditions of the Archean Earth whose chemistry permitted the emergence of biology and see how advances in Astronomy construct a context in which Earth is but one example of a multi-variate distribution.

Through observations of planets orbiting other stars than the Sun, we can investigate which Earth-like and non-Earth-like conditions can lead to biology, as well as study planets (and therefore life) through time. The frequency of inhabited planets will reveal whether mundane conditions and reactions are sufficient, or if rarer, more specific steps are required. We will go over what we know about exoplanets, describe the techniques that can discover worlds similar to the Earth and the methods that are employed to investigate their atmospheric chemistry.

Looking at Earth, a key task is to understand which conditions are required for an early life – the Archean planet looked nothing like the modern Earth.  However, we have a chemical record of the early world chemistry operating in our cell, the metabolic network, a large chemical system that connects the operating biochemical processes. We will discuss about new results which show that many of the key biochemical reactions forming this system might be direct descendants of chemical reactions that could function on the basis of sedimental transition metals, in particular iron. These chemical reactions appear to have given rise to glycolysis, the pentose phosphate pathway and the Krebs cycle, key biochemical systems that form the core of cellular biochemistry. We will discuss whether the chemical constraints that form the biochemical network would result in exobiological life to resemble ours.