Results 61 to 70 of about 34,064 (228)

Physiological Differentiation within a Single-Species Biofilm Fueled by Serpentinization

open access: yesmBio, 2011
Carbonate chimneys at the Lost City hydrothermal field are coated in biofilms dominated by a single phylotype of archaea known as Lost City Methanosarcinales. In this study, we have detected surprising physiological complexity in single-species biofilms,
William J. Brazelton   +3 more
doaj   +1 more source

Physicochemical Parameters Limiting Growth of Debaryomyces hansenii in Solutions of Hygroscopic Compounds and Their Effects on the Habitability of Martian Brines

open access: yesLife, 2021
The availability of liquid water is a prerequisite for all lifeforms on Earth. In hyperarid subzero environments like the Dry Valleys in Antarctica or the near-subsurface of Mars liquid water might be provided temporarily by hygroscopic substances that ...
Jacob Heinz   +2 more
doaj   +1 more source

Modeling pN2 through Geological Time: Implications for Planetary Climates and Atmospheric Biosignatures [PDF]

open access: yes, 2016
Nitrogen is a major nutrient for all life on Earth and could plausibly play a similar role in extraterrestrial biospheres. The major reservoir of nitrogen at Earth's surface is atmospheric N2, but recent studies have proposed that the size of this ...
Buick, R.   +5 more
core   +2 more sources

The Water Activity of Mars-relevant Multicomponent Brines: The Changing Influence of Perchlorate on Habitability over Time

open access: yesThe Planetary Science Journal, 2023
Low water activity limits the habitability of aqueous environments, and salts present on Mars are known to reduce water activity. As environmental brines are not pure solutions of a single salt, predicting their water activity is difficult without direct
Adam H. Stevens, Charles S. Cockell
doaj   +1 more source

Philosophical Aspects of Astrobiology Revisited

open access: yesPhilosophies, 2021
Given the idea that Life as we know it is nothing but a special form of a generically underlying dynamical structure within the physical Universe, we try to introduce a concept of Life that is not only derived from first principles of fundamental physics,
Rainer E. Zimmermann
doaj   +1 more source

From Cosmos to Intelligent Life: The Four Ages of Astrobiology

open access: yes, 2012
The history of life on Earth and in other potential life-bearing planetary platforms is deeply linked to the history of the universe. Since life as we know it relies on chemical elements forged in dying heavy stars, the universe needs to be old enough ...
Abel   +17 more
core   +1 more source

A Stochastic Process Approach of the Drake Equation Parameters

open access: yes, 2011
The number N of detectable (i.e. communicating) extraterrestrial civilizations in the Milky Way galaxy is usually done by using the Drake equation. This equation was established in 1961 by Frank Drake and was the first step to quantifying the SETI field.
Annis   +13 more
core   +3 more sources

Stable Nitrogen Isotope Analysis of Amino Acids by Orbitrap Mass Spectrometry: Application for Extraterrestrial Samples

open access: yesRapid Communications in Mass Spectrometry, Volume 39, Issue 23, 15 December 2025.
ABSTRACT Background Obtaining isotopic data on soluble organic compounds, such as amino acids, in extraterrestrial samples is crucial for understanding their origins, prebiotic chemistry, and potential contamination. Conventional GC‐IRMS requires grams of material to measure isotopic compositions, limiting the analysis of low‐concentration organics in ...
O. M. McIntosh   +9 more
wiley   +1 more source

Astrobiological Effects of F, G, K and M Main-Sequence Stars

open access: yes, 2008
We focus on the astrobiological effects of photospheric radiation produced by main-sequence stars of spectral types F, G, K, and M. The photospheric radiation is represented by using realistic spectra, taking into account millions or hundred of millions ...
E. F. Guinan   +4 more
core   +1 more source

Oxychlorine Species on Mars: A Review

open access: yesReviews of Geophysics, Volume 63, Issue 4, December 2025.
Abstract Oxychlorine species (mainly perchlorate and chlorate) have been identified at multiple locations on the surface of Mars by both orbiter and in situ rovers. They have also been found in martian meteorites. Cl‐isotopes in meteoritic minerals suggest that an oxychlorine cycle has been operating on the martian surface for the last ∼4 billion years.
Kaushik Mitra
wiley   +1 more source

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