The importance of continents, oceans and plate tectonics for the evolution of complex life: implications for finding extraterrestrial civilizations

• Published in: Scientific reports 2024-04, Vol.14 (1), p.8552-8552, Article 8552
• Main Authors: Stern, Robert J., Gerya, Taras V.
• Format: Article
• Language: English
• Subjects: 704/2151/210; 704/445/3929; Continents; Evolution; Humanities and Social Sciences; multidisciplinary; Oceans; Plate tectonics; Science; Science (multidisciplinary); Tectonics
• ISSN: 2045-2322; 2045-2322
• DOI: 10.1038/s41598-024-54700-x

Within the uncertainties of involved astronomical and biological parameters, the Drake Equation typically predicts that there should be many exoplanets in our galaxy hosting active, communicative civilizations (ACCs). These optimistic calculations are however not supported by evidence, which is often referred to as the Fermi Paradox. Here, we elaborate on this long-standing enigma by showing the importance of planetary tectonic style for biological evolution. We summarize growing evidence that a prolonged transition from Mesoproterozoic active single lid tectonics (1.6 to 1.0 Ga) to modern plate tectonics occurred in the Neoproterozoic Era (1.0 to 0.541 Ga), which dramatically accelerated emergence and evolution of complex species. We further suggest that both continents and oceans are required for ACCs because early evolution of simple life must happen in water but late evolution of advanced life capable of creating technology must happen on land. We resolve the Fermi Paradox (1) by adding two additional terms to the Drake Equation: f oc (the fraction of habitable exoplanets with significant continents and oceans) and f pt (the fraction of habitable exoplanets with significant continents and oceans that have had plate tectonics operating for at least 0.5 Ga); and (2) by demonstrating that the product of f oc and f pt is very small (