New discoveries in astronomy and biology continue to point to Panspermia as the most likely mode of the origin of life on Earth. This paper builds upon the work done by W.M. Napier, 2004 1 , and re-estimates the time for the seeding of the galaxy given the latest 2013 estimates from the Kepler Mission data. We present this "thought experiment" in the form of an opinion paper. We calculate that, from a single point source of origin, the full colonisation of the entire Milky Way galaxy by primitive microbes will take place in a timescale less than the average age of low-mass stars in the galactic disc, 10 10 yr (i.e., 10 billion years ago; bya). Our calculation is independent of the location of the "point-source" . The writers believe the probability of the point-source being Earth is infinitesimal compared with it being elsewhere in the galaxy.
We discuss a wide range of data emerging from the Rosetta Mission that all point indirectly to biological activity in Comet 67P/Churyumov-Gerasimenko. The existence of cracks and fissures on a smooth surface terrain apparently resealed, as well as early outgassing activity are consistent with the existence of subsurface lakes in which biological activity builds up high pressures of volatile gases that sporadically ruptures a frozen icy crust. While microorganisms probably require liquid water bodies for their early colonising of a comet, they can inhabit cracks in ice and sub-crustal snow, especially if they contain antifreeze salts and biopolymers. Some organisms metabolise at temperatures as low as 230 K, explaining the coma of Comet 97P out at 3.9AU and our prediction is that they would become increasingly active in the near-surface layers as the comet approaches its 1.3 AU perihelion. The detection of an overwhelming abundance of complex organic molecules at the surface by Philae and through IR imaging by the Rosetta orbiter is most significant.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.