Origin & Evolution of Life

Strong Evidence That Abiogenesis Is a Rapid Process on Earth Analogs

By Keith Cowing

Press Release

April 9, 2025

Filed under abiogenesis, Biosignatures, biosphere, Earth-like Planet, evolution, microfossil

Strong Evidence That Abiogenesis Is a Rapid Process on Earth Analogs — Odds ratio of the hypotheses that abiogenesis is a fast vs slow process. Each curve represents the odds ratio, computed using Equation 1, as a function of the biosphere’s ultimate lifespan, T – although we have subtracted off the modern epoch to yield remaining time on the x-axis. Previous estimates [1, 8] for the earliest evidence of life yield the dotted and dashed lines, but the new LUCA date of 4.2 Gya [10] greatly improves the odds factor. Indeed, the three solid lines show how the odds are always above 10:1 irrespective of how one chooses T or indeed fairly extreme choices (Carboniferious and Cambrian period) for the earliest civilization on Earth, t ′ I – evident by the circles which denote the minima. — astro-ph.EP

The early start to life naively suggests that abiogenesis is a rapid process on Earth-like planets. However, if evolution typically takes ~4Gyr to produce intelligent life-forms like us, then the limited lifespan of Earth’s biosphere (~5-6Gyr) necessitates an early (and possibly highly atypical) start to our emergence – an example of the weak anthropic principle.

Our previously proposed objective Bayesian analysis of Earth’s chronology culminated in a formula for the minimum odds ratio between the fast and slow abiogenesis scenarios (relative to Earth’s lifespan). Timing from microfossils (3.7Gya) yields 3:1 odds in favor of rapid abiogenesis, whereas evidence from carbon isotopes (4.1Gya) gives 9:1, both below the canonical threshold of “strong evidence” (10:1).

However, the recent result of a 4.2Gya LUCA pushes the odds over the threshold for the first time (nominally 13:1). In fact, the odds ratio is >10:1 for all possible values of the biosphere’s ultimate lifespan and speculative hypotheses of ancient civilizations. For the first time, we have formally strong evidence that favors the hypothesis that life rapidly emerges in Earth-like conditions (although such environments may themselves be rare).

Comments: Accepted for publication in Astrobiology
Subjects: Earth and Planetary Astrophysics (astro-ph.EP)
Cite as: arXiv:2504.05993 [astro-ph.EP] (or arXiv:2504.05993v1 [astro-ph.EP] for this version)
https://doi.org/10.48550/arXiv.2504.05993
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Submission history
From: David Kipping
[v1] Tue, 8 Apr 2025 12:55:50 UTC (97 KB)
https://arxiv.org/abs/2504.05993
Astrobiology

Keith Cowing

Explorers Club Fellow, ex-NASA Space Station Payload manager/space biologist, Away Teams, Journalist, Lapsed climber, Synaesthete, Na’Vi-Jedi-Freman-Buddhist-mix, ASL, Devon Island and Everest Base Camp veteran, (he/him) 🖖🏻

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