Beyond Goldilocks: the role of phosphorus in seeding life in the cosmos
Phosphorus (P) is a key element for life. The environmental availability of P is a key open question in life’s origins of Earth and the biomass of Earth over time. From this, it follows that the distribution of P in the universe will correlate to some degree with the distribution of life, too. Research on these topics is undergoing a major shift at present, with new ideas energising the search for life’s origins, evolution, and distribution beyond Earth. I will touch on all three of these topics, presenting my work into prebiotic environments that had a high input rate of P; the accumulation of P in Earth’s crust over time; and the likely distribution of P-rich versus P-poor worlds in the cosmos. A key emerging result from these studies is that Earth appears to be optimised for P-availability to life. In other words, Earth does not just occupy the habitable zone with respect to the presence of liquid water on its surface, but also occupies a chemical habitable zone. Few other equally ancient worlds in the galaxy are likely to meet the chemical and physical parameters that optimised Earth for life. On this basis, humanity may yet turn out to be the first space-faring civilisation to have emerged at least in our galaxy.