CONSTRAINTS ON THE ORIGIN OF LIFE ON EARTH DUE TO THE PHYSICS OF THE ANCIENT SUN

J. Chela-Flores 1,2 and M. Messerotti 3

[1] The Abdus Salam ICTP, Strada Costiera 11, 34014 Trieste, Italia
[2] Instituto de Estudios Avanzados, IDEA, Caracas 1015A, Venezuela
[3] INAF-Trieste Astronomical Observatory, Loc. Basovizza n. 302, 34012 Trieste, Italia

ABSTRACT

An important factor for understanding the origin and evolution of life on Earth is the evolution of the Sun itself, especially the evolution of space climate and space weather. In the present work we consider constraints on the emergence of life imposed by our knowledge of the early Sun, as well as from the early Solar System. Ancient space weather can be inferred to a large extent from particles that have been emitted by the Sun and have left tracks in the geologic samples from the Hadean (4.6 - 3.8 billion years before the present, Gyr BP) and the Archean (3.8 - 2.5 Gyr BP). We take into account the biogeochemistry associated with the fractionation of the stable isotopes of biogenic elements, especially sulfur. The presence of ultraviolet radiation (UVR) on the early Earth is confronted with the possibility that microorganisms, as we know them from contemporary biota, could originate, survive, and evolve even under the effect of harsher solar activity prevailing on the early Earth. Finally, we discuss the conditions that have been favorable for the phenomenon of the origin of life in the early Solar System. The search for a second example of life would add a significant factor in our understanding of the physical relations that were favorable for the phenomenon of the origin of life. We explore what could be gained from solar missions that would be capable of clarifying whether life could have emerged not only on early Earth, but also on the Jovian satellite Europa.