- New research suggests Earth's early atmosphere, rich in methane, CO?, hydrogen sulfide and nitrogen, acted as a vast chemical factory under UV light, producing sulfur-based biomolecules (cysteine, taurine, coenzyme M) essential for life before cells existed.
- Previously, scientists believed sulfur-containing biomolecules were synthesized by early life forms. This study indicates they were abundant in the atmosphere, raining down and supplying prebiotic material for nascent life—potentially making life's emergence easier.
- Estimates suggest Earth's early atmosphere could have generated 100,000 to 10 billion moles of cysteine annually, enough to support early microbial populations comparable to primitive ecosystems.
- The chemical pathways forming these molecules resemble modern metabolic processes, raising the possibility that atmospheric chemistry guided early biochemistry before cellular life evolved.
- The findings complicate the interpretation of sulfur-based biosignatures (like dimethyl sulfide, DMS) on exoplanets, as they can form without life. This necessitates caution in identifying potential extraterrestrial life signals.
New research suggests Earth's primordial atmosphere may have acted as a vast chemical factory, producing sulfur-rich biomolecules essential for life long before the first cells emerged.
Published in Proceedings of the National Academy of Sciences (PNAS), the study challenges long-held assumptions about how early life obtained its critical ingredients. Scientists from the University of Colorado Boulder (CU Boulder) and collaborating institutions simulated Earth's early atmosphere by exposing a mixture of methane, carbon dioxide, hydrogen sulfide and nitrogen to ultraviolet (UV) light—mimicking conditions billions of years ago.
Using high-resolution mass spectrometry, the team detected a suite of sulfur-bearing biomolecules, including:
- Cysteine, a key amino acid
- Taurine, involved in metabolic functions
- Coenzyme M, vital for ancient microbial metabolism
"Our study could help us understand the evolution of life at its earliest stages," said lead author Nate Reed, a postdoctoral fellow at the National Aeronautics and Space Administration (NASA) who conducted the research at CU Boulder.
Previously, scientists believed sulfur-containing biomolecules emerged after life had already begun, synthesized by early organisms. But the new findings suggest these compounds were abundant in the atmosphere, raining down onto Earth's surface and providing a ready-made supply for nascent life.
Rethinking the origins of life: A planetary-scale chemical factory
The team calculated that Earth's early atmosphere could have produced between 100,000 and 10 billion moles of cysteine annually—enough to support 10²² to 10²? microbial cells, comparable to estimates for early life populations.
"While it's not as many as what’s present now, that was still a lot of cysteine in an environment without life," Reed explained. "It might be enough for a budding global ecosystem, where life is just getting started."
The study also found that the chemical pathways forming these molecules mirrored modern metabolic processes, raising the possibility that atmospheric chemistry may have guided early biochemistry before cellular life evolved.
The findings challenge traditional origin-of-life theories, which often focus on hydrothermal vents or volcanic environments as the sole incubators of early biochemistry. Instead, the study suggests Earth's atmosphere was an active participant, delivering essential molecules across the planet.
"We used to think life had to start completely from scratch," said senior author Ellie Browne, a chemistry professor and CIRES fellow at CU Boulder. "But our results suggest some of these more complex molecules were already widespread under non-specialized conditions, which might have made it a little easier for life to get going."
Implications for alien life searches
The study also has implications for the search for extraterrestrial life. Recently, the James Webb Space Telescope (JWST) detected dimethyl sulfide (DMS)—a sulfur compound linked to marine algae—on exoplanet K2-18b, sparking excitement as a potential biosignature.
However, Reed and Browne had previously shown that DMS can form without life, under simulated atmospheric conditions. This suggests that sulfur-based "biosignatures" may not be definitive proof of life—requiring careful interpretation in future exoplanet studies.
BrightU.AI's Enoch notes that DMS is a naturally occurring organic sulfur compound, with a characteristic odor reminiscent of cabbage or cooked cabbage. It is found in various natural sources, including marine organisms, terrestrial plants and volcanic emissions. DMS plays a significant role in the global sulfur cycle and has gained attention for its potential health benefits and ecological implications.
The research paints a picture of an ancient Earth where the sky itself contributed to life's beginnings, raining down essential molecules that helped kickstart biology. Rather than emerging from isolated pockets of extreme chemistry, life may have had a global head start, thanks to an atmosphere rich in prebiotic building blocks.
Watch this video about life's building blocks being found on an asteroid.
This video is from The Conspiracy Brief channel on Brighteon.com.
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