Results 51 to 60 of about 30,578 (233)
Variable Sr Diffusion and Implications for Rb–Sr Biotite Geochronology
Journal of Metamorphic Geology, EarlyView.ABSTRACT The rubidium–strontium (Rb–Sr) system has a long pedigree as a geochronological tool that relies on the application of an isochron approach. In particular, biotite contains strongly radiogenic Rb–Sr isotopes, and thus can yield meaningful crystallisation or cooling ages via this approach. However, the response of the Rb–Sr system in biotite to
Riley Rohrer +4 more
wiley +1 more source
Life, 2016 We used Ar plasma-sterilization at a temperature below 80 °C to examine its effects on the viability of microorganisms when intermixed with tested soil.
Janosch Schirmack +3 more
doaj +1 more source
The circular nutrient economy of terrestrial ecosystems and the consequences for rock weathering
Frontiers in Environmental Science, 2023 Earth’s biosphere is thought to exert a substantial influence on regolith evolution and chemical weathering rates. However, ecosystems are also highly efficient at retaining and recycling nutrients.
Kate Maher +2 more
doaj +1 more source
Hypotheses for near-surface exchange of methane on Mars [PDF]
, 2016 The Curiosity rover recently detected a background of 0.7 ppb and spikes of 7 ppb of methane on Mars. This in situ measurement reorients our understanding of the Martian environment and its potential for life, as the current theories do not entail any ...
Bloom, A. Anthony +4 more
core +3 more sources
Noble gases and nitrogen in material from asteroid Bennu
Meteoritics &Planetary Science, EarlyView.Abstract We report the elemental and isotopic abundances of all stable noble gases (helium, neon, argon, krypton, and xenon) in eight particles from asteroid Bennu returned by NASA's OSIRIS‐REx mission. We also report nitrogen abundances and isotopic ratios that were analyzed alongside neon and argon in four additional Bennu particles.
B. Marty +7 more
wiley +1 more source
Scaling forces to asteroid surfaces: The role of cohesion
, 2010 The scaling of physical forces to the extremely low ambient gravitational acceleration regimes found on the surfaces of small asteroids is performed. Resulting from this, it is found that van der Waals cohesive forces between regolith grains on asteroid ...
Hartzell, C. M. +3 more
core +1 more source
DEM simulation of soil-tool interaction under extraterrestrial environmental effects [PDF]
, 2017 In contrast to terrestrial environment, the harsh lunar environment conditions include lower gravity acceleration, ultra-high vacuum and high (low) temperature in the daytime (night-time).
Arroyo Alvarez de Toledo, Marcos +3 more
core +2 more sources
Anhydrous minerals in asteroid Bennu: Evidence for well‐preserved primordial components
Meteoritics &Planetary Science, EarlyView.Abstract Aqueously altered carbonaceous astromaterials are dominated by secondary minerals, but a minor fraction of primary, anhydrous silicates and oxides escape alteration, offering insight into the original composition of asteroid parent bodies. We report the mineralogy, petrology, mineral chemistry, and oxygen isotopes of anhydrous minerals—50 ...
S. S. Russell +23 more
wiley +1 more source
The Apollo 15 coarse fines (4-10 mm) [PDF]
, 1989 A new catalog of the Apollo 15 coarse fines particles is presented. Powell's macroscopic descriptions, resulting from his 1972 particle by particle binocular examination of all of the Apollo 15 4 to 10 mm fines samples, are retained.
Ryder, Graham, Sherman, Sarah Bean
core +1 more source
Women in space: A review of known physiological adaptations and health perspectives
Experimental Physiology, EarlyView.Abstract Exposure to the spaceflight environment causes adaptations in most human physiological systems, many of which are thought to affect women differently from men. Since only 11.5% of astronauts worldwide have been female, these issues are largely understudied.
Millie Hughes‐Fulford +4 more
wiley +1 more source