Beginning with loose aggregations of dust particles coated with heterogeneous ices under vacuum at Kuiper Belt temperatures, moving to Jupiter/Saturn distances and eventually to low-perihelion orbit, we consider the likely development of the gaseous phase within a cometary nucleus over the course of its lifetime. From the perspective of physical chemistry, we consider limits on the spatial and temporal distribution and composition of this gaseous phase. The implications of the gaseous phase for heat transfer and for the possible spatial and temporal development of liquid phases are calculated. We conclude that the likely temperatures, pressures, and compositions beneath the outer crust of typical cometary nuclei are such that fluidised phases can exist at significant depths and that these reservoirs give a coherent explanation for the high-intensity outbursts observed from cometary nuclei at large distances from perihelion.

The European Astrobiology Network Association (EANA) coordinates and promotes astrobiology in the 17 European countries that are member of the organization. Astrobiology includes the study of the origin, evolution and distribution of life in the Universe. It is a multi-disciplinary science that encompasses the disciplines of chemistry, biology, palaeontology, geology, atmospheric physics, planetary physics and stellar physics. The open questions to be addressed and the steps ahead in cosmochemistry, star and planet formation, the chemistry of life's origin, the study of bacterial life as a reference and the search for habitats and biosignatures beyond the Earth are presented.

Monocyanopolyynes and dicyanopolyynes can be synthesized quite easily by the submerged electric arc. Monocyanopolyynes having the general formula H[bond](C[triple bond]C)n[bond]C[triple bond]N can be synthesized together with ordinary polyynes series H[bond](C[triple bond]C)n[bond]H by arcing graphite electrodes in acetonitrile. Dicyanopolyynes N[triple bond]C[bond](C[triple bond]C)n[bond]C[triple bond]N are produced almost pure by arcing graphite electrodes directly into liquid nitrogen. These molecules are present in the envelope of post-AGB (asymptotic giant branch), carbon-rich giant stars and also in dark molecular clouds. They are incorporated into comets and also into other primitive materials and may play a role in the prebiotic synthesis of more complex organic molecules having a biological significance. Furthermore, the cyanopolyynes are involved in the atmospheric chemistry of some bodies of the solar system. The discovery of the easy formation of these molecules under laboratory conditions may explain why these molecules are so ubiquitous in space and may also stimulate new ideas about the mechanism of their formation.