2005/04/01 by Paul Davies, Charles H. Lineweaver · 3 citations
Physics and Astronomy · #Space Science and Extraterrestrial Life #Astro and Planetary Science #Planetary Science and Exploration
paper · doi:10.1089/ast.2005.5.154
openalex publication_date 2005/04/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/22
If life emerges readily under Earth-like conditions, the possibility arises of multiple terrestrial genesis events. We seek to quantify the probability of this scenario using estimates of the Archean bombardment rate and the fact that life established itself fairly rapidly on Earth once conditions became favorable. We find a significant likelihood that at least one more sample of life, referred to here as alien life, may have emerged on Earth, and could have coexisted with known life. Indeed, it is difficult to rule out the possibility of extant alien life. We offer some suggestions for how an alternative sample of life might be detected.