New Fossils Suggest That Life On Earth Started Twice

Quick Overview

The claim that life on Earth started twice, once with arsenic and once with phosphorus, is highly controversial, as the newly discovered 2.1-billion-year-old fossils in Gabon, which contain arsenic-rich structures, suggest complex life evolved much earlier than previously thought, potentially undermining the idea that life is unique to Earth's current chemical makeup.

Key Points: New evidence from 2.1-billion-year-old fossils found in Gabon suggests complex life forms existed much earlier than previously accepted. These fossils contain arsenic-rich structures, leading to the controversial claim that life might have started twice, once using arsenic and once using phosphorus. The fossils found by researchers including Abderrazak El Albani exhibit shapes about a centimeter in size, larger than expected for that time period. The arsenic-rich compounds in the fossils suggest that early complex organisms developed mechanisms to cope with arsenic toxicity, possibly by sequestering it into vesicles. Post-death diagenesis involved the arsenic reacting with iron and sulfide to form arsenic-free pyrite, preserving the structures. The host rock's chemistry differs from the surrounding areas, suggesting the arsenic compounds were concentrated by biological activity, not just fluid deposits or geochemistry. The presenter notes that most geologists remain unconvinced by the evidence for arsenic-based life, contrasting it with the established phosphorus-based life origin.

Context: The video discusses a potentially paradigm-shifting scientific claim regarding the origin of life on Earth, specifically challenging the established timeline and chemical basis (phosphorus) for the first complex life forms. The controversy centers on newly discovered fossils from Gabon, aged 2.1 billion years, which appear to contain biological structures formed using arsenic instead of the expected phosphorus, suggesting a possible second genesis of life.

Detailed Analysis

Sabine Hossenfelder discusses a controversial claim that life on Earth might have started twice, once based on arsenic and once on phosphorus. This claim stems from the discovery of 2.1-billion-year-old fossils in Gabon by a research group led by Abderrazak El Albani. These fossils show complex life forms, about a centimeter in size, which is much larger than expected for that era, and the structures are rich in arsenic compounds. The process detailed in the research suggests that these ancient organisms actively sequestered arsenic inside vesicles during life (03:50) and that after death, sulfide reduction led to the formation of arsenic-free pyrite, preserving the structures (03:56). The argument against a purely chemical origin for these structures is that the surrounding rocks have a different chemistry, implying biological activity concentrated the arsenic. Hossenfelder notes the controversy, stating that many geologists are unconvinced and that the established narrative favors phosphorus-based life (04:25). She humorously suggests that if the arsenic life claim were true, it implies life might be more common in the universe than currently believed (05:58), though she concludes that the evidence so far does not definitively prove a second origin of life (05:24).