Results 41 to 50 of about 1,716 (169)
ChallengesSodium perchlorate is a toxic salt-based compound found both terrestrially, (due to pollution) and extraterrestrially on the surface of Mars. Perchlorate pollution poses a risk to agricultural-based activities as once it enters soils/waterways it can be ...
Daniel Keaney +5 more
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Methanogens Through Time and Space: Impact on Earth’s Planetary Evolution and Biogeochemistry
GeosciencesMethanogens, or methanogenic archaea (MA), are among the most ancient and widely distributed microorganisms, characterized by a unique metabolism that generates methane (CH4) as the terminal product of anaerobic respiration.
Paxton Tomko +4 more
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mSystems, 2021 In recent years, our appreciation of the extent of habitable environments in Earth’s subsurface has greatly expanded, as has our understanding of the biodiversity contained within.
Lindsay I. Putman +7 more
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Identification of the Beagle 2 lander on Mars [PDF]
Royal Society Open Science, 2017 The 2003 Beagle 2 Mars lander has been identified in Isidis Planitia at 90.43° E, 11.53° N, close to the predicted target of 90.50° E, 11.53° N. Beagle 2 was an exobiology lander designed to look for isotopic and compositional signs of life on Mars, as ...
J. C. Bridges +11 more
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A History of the Extraterrestrial Life Debate
Zygon, 1997 From antiquity to the present, humans have debated whether intelligent life exists elsewhere in the universe. This presentation will survey this debate, examining the roles played in it by science, religion, philosophy, and other areas of human learning.
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Maximum Lifetime of the Vegetative Biosphere
Journal of Geophysical Research: Atmospheres, Volume 131, Issue 11, 16 June 2026.Abstract We use a three‐dimensional model to calculate steady‐state climates at various intervals in Earth's future, across a parameter space of increasing insolation and decreasing CO2 ${\text{CO}}_{2}$ mixing ratio. Comparison with prior results shows an overestimation of warming by one‐dimensional models when solar constant is increased and CO2 ...
Jacob Haqq‐Misra, Eric Wolf
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Widespread Impact‐Induced Crustal Permeability on the Early Earth
AGU Advances, Volume 7, Issue 3, June 2026.Abstract The early Earth (i.e., Archean and Hadean Eons, 2.5–4.0 and 4.0–4.5 Ga, respectively) experienced frequent cosmic bombardment. Impacts have been shown to stimulate crustal alteration, for instance via hydrothermal systems active for up to millions of years post‐impact.
A. M. Alexander +2 more
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Light Regimes Shape Utilization of Extracellular Organic C and N in a Cyanobacterial Biofilm
mBio, 2016 Although it is becoming clear that many microbial primary producers can also play a role as organic consumers, we know very little about the metabolic regulation of photoautotroph organic matter consumption.
Rhona K. Stuart +10 more
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Predicting Nitrogen Isotope Fractionation in Nitrate Deposition on Early Mars
Journal of Geophysical Research: Planets, Volume 131, Issue 6, June 2026.Abstract Noachian and early Hesperian Mars were likely warm and wet, with an atmosphere abundant in molecular nitrogen. The recent discovery of nitrate deposits in the Yellowknife Bay mudstones at Gale Crater confirm the existence of nitrogen oxides (NOX) on Noachian Mars. The processes responsible for the production of these nitrates would fractionate
J. Shawcross +4 more
wiley +1 more source
About the presence of arsenic in prebiotic species
BIO Web of Conferences, 2014 The recent publication that some bacteria could use arsenic instead of phosphorus for building their DNA triggered a large controversy in the astro/exobiology community. Most comments claim that such a substitution is not possible.
Ellinger Y. +3 more
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