Nine requirements for the origin of Earth's life: Not at the hydrothermal vent, but in a nuclear geyser system

The origin of life on Earth remains enigmatic with diverse models and debates. Here we discuss essential requirements for the first emergence of life on our planet and propose the following nine requirements: (1) an energy source (ionizing radiation and thermal energy); (2) a supply of nutrients (P, K, REE, etc.); (3) a supply of life-constituting major elements; (4) a high concentration of reduced gases such as CH4, HCN and NH3; (5) dry-wet cycles to create membranes and polymerize RNA; (6) a non-toxic aqueous environment; (7) Na-poor water; (8) highly diversified environments, and (9) cyclic conditions, such as day-to-night, hot-to-cold etc. Based on these nine requirements, we evaluate previously proposed locations for the origin of Earth's life, including: (1) Darwin's warm little pond, leading to a prebiotic soup for life; (2) panspermia or Neo-panspermia (succession model of panspermia); (3) transportation from/through Mars; (4) a deep-sea hydrothermal system; (5) an on-land subduction-zone hot spring, and (6) a geyser systems driven by a natural nuclear reactor. We conclude that location (6) is the most ideal candidate for the origin point for Earth's life because of its efficiency in continuously supplying both the energy and the necessary materials for life, thereby maintaining the essential cradle for its initial development. We also emphasize that falsifiable working hypothesis provides an important tool to evaluate one of the biggest mysteries of the universe - the origin of life. (C) 2019, China University of Geosciences (Beijing) and Peking University. Production and hosting by Elsevier B.V.