The DOI matches its Crossref record; 89 of the 92 references it cites were found in a registry or an index.
The Early Faint Sun Paradox: Organic Shielding of Ultraviolet-Labile Greenhouse Gases
Abstract
Atmospheric mixing ratios of ∼10 −5 ± 1 for ammonia on the early Earth would have been sufficient, through the resulting greenhouse warming, to counteract the temperature effects of the faint early sun. One argument against such model atmospheres has been the short time scale for ammonia photodissociation by solar ultraviolet light. Here it is shown that ultraviolet absorption by steady-state amounts of high-altitude organic solids produced from methane photolysis may have shielded ammonia sufficiently that ammonia resupply rates were able to maintain surface temperatures above freezing.
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“Possibly, a stratospheric organic haze, such as that on Saturn’s moon, Titan, shielded tropospheric NH3 from UV (162).”
From The Archean atmosphere (2020) · cites this paper as [162]
In the citing paper
“Earlier, we noted that an organic haze might protect tropospheric ammonia from UV (162), but whether NH3 was a viable greenhouse gas is unclear.”
From The Archean atmosphere (2020) · cites this paper as [162]
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Metadata
- Authors
- Sagan, C., & Chyba, C.
- Affiliations
- University of Arizona (US)
- Venue
- Science
- Published
- 1997-05-23
- Volume
- 276
- Issue
- 5316
- Pages
- 1217-1221
- ISSN
- 0036-8075 (ISSN-L)
- 1095-9203
- OpenAlex
- W1964099544
- Cited by
- 396
- References
- 92
- Citations by year
- 2026: 7 · 2025: 10 · 2024: 12 · 2023: 11 · 2022: 8 · 2021: 9 · 2020: 18 · 2019: 5 · 2018: 14 · 2017: 14 · 2016: 11 · 2015: 7 · 2014: 16 · 2013: 25 · 2012: 17
- FWCI
- 14.02
- Type
- journal article
- Language
- en
- Open access
- closed
- Locations
- Science (publishedVersion)
- PubMed (publishedVersion)
- Topics
- Physical Sciences › Earth and Planetary Sciences › Space and Planetary Science › Astro and Planetary Science
- Physical Sciences › Earth and Planetary Sciences › Paleontology › Paleontology and Stratigraphy of Fossils
- Physical Sciences › Environmental Science › Global and Planetary Change › Earth Systems and Cosmic Evolution
- Keywords
- early Earth, ammonia, greenhouse gases, UV protection, organic solids, methane photolysis, ammonia photodissociation, atmospheric mixing ratios, surface temperature, early atmosphere
- MeSH terms
- Ammonia, Atmosphere, Carbon Dioxide, Methane, Models, Chemical, Photolysis, Ultraviolet Rays, Solar System, Greenhouse Effect, Earth, Planet, Evolution, Planetary
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