VUV and EUV Photolysis of Ices

    Experiments of ice photolysis have shown that a large number and variety of molecules of prebiotic and biological interests, including many essential amino acids, sugars like ribose, and the nucleobase uracil, can be formed via VUV/EUV irradiation of astrophysical ice mixture analogs, and identified in the resulting samples with chromatographic techniques. Since such compounds have also been detected in carbonaceous meteorites, this clearly suggests that compounds embedded in interstellar ices during the formation of the Solar System could have led to the formation of very complex organic molecules including prebiotic compounds. Complex organics may, therefore, have been delivered to telluric planets via meteorites and comets, seeding the surface and oceans of the primitive Earth, and triggering the first prebiotic reactions that led to the emergence of life on our planet nearly 4 billion years ago. Recent detection of several COMs in a comet by the Rosetta mission reinforces this scenario.