Image: arxiv.org
The Story
The strongest cautionary case begins with stellar physics: late M dwarfs emit relatively little radiation in the wavelengths used by Earth’s oxygenic photosynthesis. In an Earth-analog scenario, that could delay oxygenation and reduce the probability of animal-like complexity. Related models nevertheless show that microbial metabolisms could produce atmospheric signatures.
- A hypothetical Earth around TRAPPIST-1 would receive about 0.9% of Earth’s photosynthetically active radiation, undercutting a direct Earth-like route to oxygen-rich complexity.
- One model estimates extremely long timescales for Earth-like oxygenation and complex-life milestones under a linear relationship between photons and biological productivity.
- A broader evolutionary model concludes that low-mass M-dwarf environments may support less biological diversity or complexity than Earth-like systems.
Deeper Insight
The low-light argument may overextend Earth’s history into a different stellar environment. TRAPPIST-1e’s atmospheric chemistry could make ozone and oxidation develop more efficiently than on Earth, potentially enabling oxygenic respiration sooner. Pre-oxygen photosynthetic ecosystems also offer routes to substantial biological activity without modern-Earth oxygen levels.
- A 2026 coupled climate-photochemical model finds that ozone forms more efficiently on TRAPPIST-1e, potentially allowing a Great Oxidation Event up to 1 billion years earlier than Earth’s.
- That model finds oxygen levels could eventually enable oxygenic respiration and animal development, challenging a permanently microbial scenario.
- Pre-oxygen photosynthesizing life could generate atmospheric biosignatures before an Earth-like oxygen atmosphere exists.
Sources · 8
Featured · Primary source · arxiv.org
Dearth of Photosynthetically Active Radiation Suggests No Complex Life on Late M-Star Exoplanets
Dearth of Photosynthetically Active Radiation Suggests No Complex Life on Late M-Star Exoplanets # Dearth of Photosynthetically Active Radiation Suggests No Complex Life on Late M-Star Exoplanets Joseph J. Soliz1 and William F. Welsh1 1Department of Astronomy, San Diego State University San Diego, U
Read sourcePrimary source · preview-www.nature.com
Possible favored great oxidation event scenario on exoplanets around M-stars with the example of TRAPPIST-1e | Scientific Reports
Possible favored great oxidation event scenario on exoplanets around M-stars with the example of TRAPPIST-1e | Scientific Reports ## Abstract The Great Oxidation Event (GOE), which marked the transition from an anoxic to an oxygenated atmosphere, occurred 2.4 billion years ago on Earth, several hund
Read sourcePrimary source · ar5iv.labs.arxiv.org
[2404.11611] Biosignatures from pre-oxygen photosynthesising life on TRAPPIST-1e
[2404.11611] Biosignatures from pre-oxygen photosynthesising life on TRAPPIST-1e \chemsetup modules = reactions # Biosignatures from pre-oxygen photosynthesising life on TRAPPIST-1e Jake K. Eager-Nash, ${}^{1,2}$ Stuart J. Daines, ${}^{3}$ James W. McDermott, ${}^{1,7}$ Peter Andrews, ${}^{1}$ Lucy
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