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OATS-DAUT SEMINAR
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Speaker: Julian CHELA-FLORES (ICTP-Trieste)

Title: Astrobiology and Astronomy: Their Common Frontiers

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Abstract: The new science of astrobiology studies the origin, evolution, distribution and destiny of life in the universe. It is these last two aspects of astrobiology (distribution and destiny) that have a common frontier with astronomy and other space sciences. We begin with bioastronomy: it concerns mainly the search for life in our galaxy by means of radio and optical astronomy. A more recent aspect of the joint research of astronomers and astrobiologists is restricted to the Solar System, where an important factor for understanding the origin and evolution of life on Earth, and possibly elsewhere, is the evolution of the Sun itself. We consider constraints on the emergence of life imposed by our knowledge of the early Solar System. We take into account the biogeochemistry associated with the fractionation of the stable isotopes of the biogenic elements, especially sulfur. The presence of ultraviolet radiation 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 earlier solar radiation. Finally, we discuss the search for a second example of life that would improve our understanding of its origin. We discuss possible solar missions that could clarify whether life could have emerged not only on the early Earth, but also on Europa, the Galilean satellite.
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