1) The study measured the conditions needed for ice nucleation on Martian dust analogs in a simulated Martian atmosphere.
2) It found that ice nucleation requires much greater supersaturation than estimated by traditional models, and that there is a strong temperature dependence not predicted by theory.
3) The high supersaturations needed for nucleation, along with observed uptake of water onto clay and dust particles, suggests that supercooled water could be stable under Martian conditions and allow for liquid-phase chemistry involving water on Mars.
Artigo mostra resultados obtidos com o OSIRIS que mostra manchas brilhantes na superfície do cometa 67P/Churyumov-Gerasimenko, interpretadas como sendo gelo de água e provadas via experimentos de laboratório.
1) Astronomers observed comet Hale-Bopp at 30.7 AU from the Sun using the ESO 2.2m telescope in Chile on December 4, 2010.
2) They detected the comet with a total brightness of R=23.3 mag, corresponding to an absolute brightness of R(1,1,0)=8.3 mag.
3) The profile of the comet was star-like without any evidence of an extended coma or tail, indicating a cessation of matter production from the comet. However, the measured brightness corresponds to a reflecting surface area nine times smaller than three years prior, suggesting some low-level activity may still be occurring.
3d modeling of_gj1214b_atmosphere_formation_of_inhomogeneous_high_cloouds_and...Sérgio Sacani
Uma equipe de cientistas da Universidade de Washington e da Universidade de Toronto foram os primeiros a simular nuvens exóticas em 3D na atmosfera de um exoplaneta.
O objeto em questão, é o GJ 1214b, um exoplaneta chamado de mini-Netuno que foi descoberto, seis anos atrás pelos astrônomos no Harvard-Smithsonian Center for Astrophysics.
Também conhecido como Gliese 1214b, esse mundo tem cerca de 2.7 vezes o diâmetro da Terra e uma massa quase 7 vezes maior que a massa do nosso planeta. Ele está localizado a cerca de 52 anos-luz de distância na constelação de Ophiuchus.
O planeta orbita a estrela anã vermelha, GJ 1214, a cada 38 horas, a uma distância de 1.3 milhões de milhas.
De acordo com estudos prévios, o planeta tem uma atmosfera rica em água ou hidrogênio com extensas nuvens.
“Deve existir altas nuvens ou uma névoa orgânica na atmosfera – como nós observamos em Titã. Sua temperatura atmosférica excede o ponto de fusão da água”, disse o Dr. Benjamin Charnay, um dos membros da equipe da Universidade de Washington.
This document summarizes NMR measurements on core plugs from an iron-rich, glauconitic sandstone reservoir in Australia that showed the mineral iron content affected NMR T2 relaxation times. Capillary pressure measurements showed the standard 30 msec T2 cutoff needed to be lowered to calibrate irreducible water saturation from NMR. Although iron affected T2 distributions, permeability could still be estimated accurately from NMR. High iron content (3-31% glauconite, 1-17% total iron) in this reservoir raised concerns about NMR surface relaxation effects.
This document discusses different types and measurements of porosity in geological formations. It defines total, effective, isolated, macro, and micro porosities based on specific criteria. It introduces the concept of "producible porosity," which refers to the interconnected pore volume that contains movable fluids like water and hydrocarbons, excluding irreducible water trapped by capillary forces or bound to clay. The document examines how total porosity measured by well logs can overestimate core porosity measurements in shaley formations, and describes using mineralogical models to more accurately calculate total porosity from logs.
Spectral gamma logs record radiation from potassium, thorium, and uranium, which can be used to evaluate clay content and type as well as source rock potential. Diffused gamma-ray logs use a gamma source and two detectors to measure photoelectric absorption and Compton scattering, related to lithology and bulk density. Open-hole logging performs measurements in uncased wells while cased-hole logging obtains data through the well casing.
The document discusses using core data from carbonate rock samples to model NMR well log responses. It contains core data like T1 and T2 distributions from NMR experiments on different carbonate rock types. This data is used to simulate raw NMR well logs by matching acquisition parameters and modeling fluid properties. Fluid substitution and inversion modeling are also used to evaluate fluid identification and the effect of acquisition settings on interpretation. The goal is to calibrate well log NMR data using the detailed core measurements and better understand NMR responses in carbonate reservoirs.
Artigo mostra resultados obtidos com o OSIRIS que mostra manchas brilhantes na superfície do cometa 67P/Churyumov-Gerasimenko, interpretadas como sendo gelo de água e provadas via experimentos de laboratório.
1) Astronomers observed comet Hale-Bopp at 30.7 AU from the Sun using the ESO 2.2m telescope in Chile on December 4, 2010.
2) They detected the comet with a total brightness of R=23.3 mag, corresponding to an absolute brightness of R(1,1,0)=8.3 mag.
3) The profile of the comet was star-like without any evidence of an extended coma or tail, indicating a cessation of matter production from the comet. However, the measured brightness corresponds to a reflecting surface area nine times smaller than three years prior, suggesting some low-level activity may still be occurring.
3d modeling of_gj1214b_atmosphere_formation_of_inhomogeneous_high_cloouds_and...Sérgio Sacani
Uma equipe de cientistas da Universidade de Washington e da Universidade de Toronto foram os primeiros a simular nuvens exóticas em 3D na atmosfera de um exoplaneta.
O objeto em questão, é o GJ 1214b, um exoplaneta chamado de mini-Netuno que foi descoberto, seis anos atrás pelos astrônomos no Harvard-Smithsonian Center for Astrophysics.
Também conhecido como Gliese 1214b, esse mundo tem cerca de 2.7 vezes o diâmetro da Terra e uma massa quase 7 vezes maior que a massa do nosso planeta. Ele está localizado a cerca de 52 anos-luz de distância na constelação de Ophiuchus.
O planeta orbita a estrela anã vermelha, GJ 1214, a cada 38 horas, a uma distância de 1.3 milhões de milhas.
De acordo com estudos prévios, o planeta tem uma atmosfera rica em água ou hidrogênio com extensas nuvens.
“Deve existir altas nuvens ou uma névoa orgânica na atmosfera – como nós observamos em Titã. Sua temperatura atmosférica excede o ponto de fusão da água”, disse o Dr. Benjamin Charnay, um dos membros da equipe da Universidade de Washington.
This document summarizes NMR measurements on core plugs from an iron-rich, glauconitic sandstone reservoir in Australia that showed the mineral iron content affected NMR T2 relaxation times. Capillary pressure measurements showed the standard 30 msec T2 cutoff needed to be lowered to calibrate irreducible water saturation from NMR. Although iron affected T2 distributions, permeability could still be estimated accurately from NMR. High iron content (3-31% glauconite, 1-17% total iron) in this reservoir raised concerns about NMR surface relaxation effects.
This document discusses different types and measurements of porosity in geological formations. It defines total, effective, isolated, macro, and micro porosities based on specific criteria. It introduces the concept of "producible porosity," which refers to the interconnected pore volume that contains movable fluids like water and hydrocarbons, excluding irreducible water trapped by capillary forces or bound to clay. The document examines how total porosity measured by well logs can overestimate core porosity measurements in shaley formations, and describes using mineralogical models to more accurately calculate total porosity from logs.
Spectral gamma logs record radiation from potassium, thorium, and uranium, which can be used to evaluate clay content and type as well as source rock potential. Diffused gamma-ray logs use a gamma source and two detectors to measure photoelectric absorption and Compton scattering, related to lithology and bulk density. Open-hole logging performs measurements in uncased wells while cased-hole logging obtains data through the well casing.
The document discusses using core data from carbonate rock samples to model NMR well log responses. It contains core data like T1 and T2 distributions from NMR experiments on different carbonate rock types. This data is used to simulate raw NMR well logs by matching acquisition parameters and modeling fluid properties. Fluid substitution and inversion modeling are also used to evaluate fluid identification and the effect of acquisition settings on interpretation. The goal is to calibrate well log NMR data using the detailed core measurements and better understand NMR responses in carbonate reservoirs.
The document provides an overview of neutron logs. It discusses the different types of neutron logs including dual spacing neutron, dual spacing epithermal neutron, and compensated neutron logs. It explains that neutron logs can be used in open or cased holes to measure neutron porosity. The measurement principle involves neutrons interacting with formation nuclei to determine hydrogen content and lithology. Presentations overlay neutron porosity on density or resistivity scales for evaluation.
1) The study reports a new Re-Os dating of 4.21 ± 0.13 Ga for the lunar impact melt rock sample 67935 collected near the Nectaris basin.
2) This age is significantly older than previous Ar-Ar ages for Apollo 16 samples but is consistent with some older proposed ages for the Nectaris basin.
3) An older age of 4.2 Ga for the Nectaris basin formation would decrease the estimated lunar accretion rate during the proposed Late Heavy Bombardment period and weaken the hypothesis of an intense impact spike around 3.9 Ga.
The document discusses NMR petrophysics and how NMR measurements fit within the broader field. It describes how NMR can provide primary measurements of porosity and fluid characterization, and secondary measurements of pore size distribution, fluid saturation, and wettability. NMR does not directly measure permeability but can provide parameters useful for permeability calculations, such as porosity, mean pore size, and fluid partitions.
This document summarizes a study on large-eddy simulations of transcritical round jets. Modeling supercritical flows is challenging due to the complex transport phenomena and rapid variation of thermodynamic properties. The study examines simulations of nitrogen jets at 40 bar, both transcritical and supercritical conditions. Results show that the supercritical jet develops faster and enhances heat transfer through increased surface wrinkling. Fully developed turbulence in both jets exhibits self-preserving behavior, with density and velocity profiles similar to low-pressure jets. Quantitative agreement is found with experimental centerline data.
This document describes a scenario to test models of the transport of radioactive contaminants from soil to surface water. It focuses on the wash-off of Cesium-137 and Strontium-90 from two experimental plots near Chernobyl following rainfall. One plot was subjected to heavy rain, the other to snowmelt. The scenario provides data on the initial radionuclide deposition, soil characteristics, and time-varying precipitation. It requests predictions of the vertical distribution of radionuclide forms in the soil, radionuclide concentrations in runoff water, and total radionuclide amounts removed from the soil by runoff. Measured data are available for model validation.
This document describes a study that determines the relative abundances of elements in the warm absorber of the active galaxy Mrk 509 using X-ray spectra from XMM-Newton and Chandra observations. The study finds relative abundances that are consistent with proto-solar values, with the exception of sulfur which is slightly underabundant. Specifically, the study measures relative abundances of carbon, nitrogen, neon, magnesium, silicon, sulfur, calcium, and iron with respect to oxygen. These abundances provide information about the enrichment processes in the host galaxy and can be compared to abundances measured in other galaxies to study abundance evolution.
This document provides information about neutron porosity logs. It begins with an introduction to porosity estimation using neutron logs and comparing the mass of hydrogen to neutrons. It then provides examples of how porosity measurements would differ based on the fluid (water vs gas) and content (increased porosity means more hydrogen). The rest of the document discusses various aspects of neutron logs like slowing of neutrons, tools used, effects of shale and chlorine, and how investigation depth varies with porosity. It concludes with a case study example from the Volve oil field to identify water and oil bearing zones from well log data.
Well logging and interpretation techniques asin b000bhl7ouAhmed Raafat
This document provides an introduction to sedimentary rock properties for well log interpretation. It discusses how sedimentary rocks form from the weathering and alteration of existing rocks. Sedimentary rocks are composed mainly of minerals stable under normal surface conditions and may be classified as mechanically or chemically derived. Mechanical rocks include sandstones and conglomerates, while chemical rocks include carbonates and evaporites. Well logs are useful for characterizing sedimentary rocks and pore fluids in order to understand petroleum reservoirs.
This document provides information on formation evaluation from well logs, including determining porosity, permeability, water saturation, and identifying depleted gas reservoirs. It discusses:
1. Using density and neutron logs to determine porosity in gas-filled reservoirs, and relying on density logs for porosity in oil reservoirs due to clay effects.
2. Calculating water saturation using resistivity logs and accounting for formation water resistivity based on known water saturated zones.
3. Methods for estimating permeability, including using core data, pressure decline testing, porosity-permeability plots, and resistivity and SP logs.
4. Identifying depleted gas reservoirs by looking for large separation between density and neutron porosity logs,
This publication discusses use of quartz crystal microbalance in combination with the Knudsen Method for rapid determination of vapor pressure of low volatility compounds
1) The study compared initializing the RothC soil carbon model with measured vs. modelled carbon pools from grassland sites.
2) For most sites, initializing with measured vs. modelled pools produced similar projected changes in soil organic carbon from 2021-2060 under climate change scenarios.
3) For some sites, differences were found, likely due to differences in drainage affecting decomposition rates of resistant plant material not captured in the modelled pools.
Thermal models of Mercury's north polar region show that:
1) Spatially, regions of high radar backscatter match predictions of where water ice would be thermally stable.
2) MESSENGER measurements found bright surfaces in the coldest areas, and dark surfaces in warmer areas, where water ice would only be stable below ground.
3) The dark surface layer is proposed to be a lag deposit rich in impact-derived organics that has formed from subsurface water ice sublimation.
Thermal models of Mercury's north polar region show that spatially distributed regions of high radar backscatter match predictions of thermally stable water ice. MESSENGER measurements find bright surfaces in coldest areas where water ice is predicted to be stable, and dark surfaces in warmer areas where it is only stable below surface. The dark layer may be a sublimation lag deposit rich in impact-derived organic material. Water ice best explains Mercury's anomalous radar features based on thermal stability comparisons to other volatiles.
The document describes calculating the viscosity of a hydrous, leucogranitic melt using a regression model. It provides background on estimating magma viscosity and factors that influence it like temperature, water content, and crystal content. It then presents the problem of calculating the viscosity of a rhyolite magma at 900°C with 2% water and 0.03% crystal content. A plan is outlined to implement a VFT model to calculate melt viscosity and incorporate crystal content using an equation to find the final magma viscosity. A spreadsheet is presented carrying out these calculations.
This document summarizes modeling of low-temperature chemical alteration of martian basalt by water. Two scenarios were modeled: open system, where the system exchanges gases with the atmosphere; and closed system, sealed from the atmosphere. In the open system, alteration yields clays and carbonates, with near-neutral pH water. In the closed system, alteration yields clays and serpentine, with strongly alkaline water and reducing gases like H2 and CH4 forming at high pressures. The models provide insights into volatile storage during aqueous alteration on Mars' surface.
The document describes climate modeling experiments of Neoproterozoic conditions using an Earth system model. It explores scenarios ranging from a full "Snowball Earth" to a less severe "Slushball Earth" hypothesis. The model results support a Slushball scenario, with moderately cold global temperatures, ice-free ocean areas near the equator, and a functioning hydrological cycle. A Snowball scenario occurred only under extreme conditions. Higher atmospheric CO2 levels would be required to escape a full glaciation and avoid a "freeze-fry" super-greenhouse situation. Future studies should better model ocean currents and refine paleogeography and CO2 levels needed to melt a Snowball Earth.
This article discusses findings from the MESSENGER spacecraft revealing details about Mercury's dynamic atmosphere. The spacecraft found that Mercury's polar regions contain large amounts of water ice, fulfilling predictions. However, measurements also surprisingly showed that the laser altimeter detected very low reflectance of Mercury's surface in polar regions, indicating it is coated in a dark, absorbing material in addition to water ice. Further studies are needed to understand the nature and origin of this dark material.
Late Noachian Icy Highlands climate model: Exploring the possibility of trans...Sérgio Sacani
The nature of the Late Noachian climate of Mars remains one of the outstanding questions in the
study of the evolution of martian geology and climate. Despite abundant evidence for flowing water (valley
networks and open/closed basin lakes), climate models have had difficulties reproducing mean annual
surface temperatures (MAT) > 273 K in order to generate the “warm and wet” climate conditions presumed
to be necessary to explain the observed fluvial and lacustrine features. Here, we consider a “cold
and icy” climate scenario, characterized by MAT ∼225 K and snow and ice distributed in the southern
highlands, and ask: Does the formation of the fluvial and lacustrine features require continuous “warm
and wet” conditions, or could seasonal temperature variation in a “cold and icy” climate produce suffi-
cient summertime ice melting and surface runoff to account for the observed features? To address this
question, we employ the 3D Laboratoire de Météorologie Dynamique global climate model (LMD GCM) for
early Mars and (1) analyze peak annual temperature (PAT) maps to determine where on Mars temperatures
exceed freezing in the summer season, (2) produce temperature time series at three valley network
systems and compare the duration of the time during which temperatures exceed freezing with seasonal
temperature variations in the Antarctic McMurdo Dry Valleys (MDV) where similar fluvial and lacustrine
features are observed, and (3) perform a positive-degree-day analysis to determine the annual volume
of meltwater produced through this mechanism, estimate the necessary duration that this process must
repeat to produce sufficient meltwater for valley network formation, and estimate whether runoff rates
predicted by this mechanism are comparable to those required to form the observed geomorphology of
the valley networks.
Water ice is thought to be trapped in large permanently shadowed regions in the Moon’s polar regions, due to their extremely
low temperatures. Here, we show that many unmapped cold traps exist on small spatial scales, substantially augmenting the
areas where ice may accumulate. Using theoretical models and data from the Lunar Reconnaissance Orbiter, we estimate the
contribution of shadows on scales from 1 km to 1 cm, the smallest distance over which we find cold-trapping to be effective for
water ice. Approximately 10–20% of the permanent cold-trap area for water is found to be contained in these micro cold traps,
which are the most numerous cold traps on the Moon. Consideration of all spatial scales therefore substantially increases the
number of cold traps over previous estimates, for a total area of ~40,000 km2, about 60% of which is in the south. A majority of
cold traps for water ice is found at latitudes > 80° because permanent shadows equatorward of 80° are typically too warm to
support ice accumulation. Our results suggest that water trapped at the lunar poles may be more widely distributed and accessible
as a resource for future missions than previously thought.
1) Global climate models that include sophisticated cloud schemes show that tidally locked planets can develop thick water clouds near the substellar point due to strong convection. These clouds greatly increase the planetary albedo and stabilize temperatures, allowing habitability at twice the stellar flux previously thought possible.
2) The cloud feedback is stabilizing, as higher stellar flux produces stronger convection and higher albedos. Substellar clouds can block outgoing radiation, reducing the day-night temperature contrast.
3) Non-tidally locked planets do not experience this stabilizing cloud feedback, as clouds only form over parts of the tropics and mid-latitudes. Their albedo decreases with increasing stellar flux, producing a destabil
Creating Comfortable Air Conditions in Mars for a Sample Volume ShelterSamet Baykul
DATE: 2019.01
In this project, it is aimed to create a theoretical climate conditions for a sample volume room - shelter enough for 6 people to live inside. The shelter is designed to be as a cylinder shaped, which has the radius of 8m and 5m of height. The climate conditions inside the shelter is designed to be identical with earth conditions in comfort, which is 22°C and %50 relative humidity. The psychrometric processes and heat transfer phenomena is calculated and necessary operations are shown.
- Calculation of heat loss and humidity
- Literature survey for recent academic studies related topic
The document provides an overview of neutron logs. It discusses the different types of neutron logs including dual spacing neutron, dual spacing epithermal neutron, and compensated neutron logs. It explains that neutron logs can be used in open or cased holes to measure neutron porosity. The measurement principle involves neutrons interacting with formation nuclei to determine hydrogen content and lithology. Presentations overlay neutron porosity on density or resistivity scales for evaluation.
1) The study reports a new Re-Os dating of 4.21 ± 0.13 Ga for the lunar impact melt rock sample 67935 collected near the Nectaris basin.
2) This age is significantly older than previous Ar-Ar ages for Apollo 16 samples but is consistent with some older proposed ages for the Nectaris basin.
3) An older age of 4.2 Ga for the Nectaris basin formation would decrease the estimated lunar accretion rate during the proposed Late Heavy Bombardment period and weaken the hypothesis of an intense impact spike around 3.9 Ga.
The document discusses NMR petrophysics and how NMR measurements fit within the broader field. It describes how NMR can provide primary measurements of porosity and fluid characterization, and secondary measurements of pore size distribution, fluid saturation, and wettability. NMR does not directly measure permeability but can provide parameters useful for permeability calculations, such as porosity, mean pore size, and fluid partitions.
This document summarizes a study on large-eddy simulations of transcritical round jets. Modeling supercritical flows is challenging due to the complex transport phenomena and rapid variation of thermodynamic properties. The study examines simulations of nitrogen jets at 40 bar, both transcritical and supercritical conditions. Results show that the supercritical jet develops faster and enhances heat transfer through increased surface wrinkling. Fully developed turbulence in both jets exhibits self-preserving behavior, with density and velocity profiles similar to low-pressure jets. Quantitative agreement is found with experimental centerline data.
This document describes a scenario to test models of the transport of radioactive contaminants from soil to surface water. It focuses on the wash-off of Cesium-137 and Strontium-90 from two experimental plots near Chernobyl following rainfall. One plot was subjected to heavy rain, the other to snowmelt. The scenario provides data on the initial radionuclide deposition, soil characteristics, and time-varying precipitation. It requests predictions of the vertical distribution of radionuclide forms in the soil, radionuclide concentrations in runoff water, and total radionuclide amounts removed from the soil by runoff. Measured data are available for model validation.
This document describes a study that determines the relative abundances of elements in the warm absorber of the active galaxy Mrk 509 using X-ray spectra from XMM-Newton and Chandra observations. The study finds relative abundances that are consistent with proto-solar values, with the exception of sulfur which is slightly underabundant. Specifically, the study measures relative abundances of carbon, nitrogen, neon, magnesium, silicon, sulfur, calcium, and iron with respect to oxygen. These abundances provide information about the enrichment processes in the host galaxy and can be compared to abundances measured in other galaxies to study abundance evolution.
This document provides information about neutron porosity logs. It begins with an introduction to porosity estimation using neutron logs and comparing the mass of hydrogen to neutrons. It then provides examples of how porosity measurements would differ based on the fluid (water vs gas) and content (increased porosity means more hydrogen). The rest of the document discusses various aspects of neutron logs like slowing of neutrons, tools used, effects of shale and chlorine, and how investigation depth varies with porosity. It concludes with a case study example from the Volve oil field to identify water and oil bearing zones from well log data.
Well logging and interpretation techniques asin b000bhl7ouAhmed Raafat
This document provides an introduction to sedimentary rock properties for well log interpretation. It discusses how sedimentary rocks form from the weathering and alteration of existing rocks. Sedimentary rocks are composed mainly of minerals stable under normal surface conditions and may be classified as mechanically or chemically derived. Mechanical rocks include sandstones and conglomerates, while chemical rocks include carbonates and evaporites. Well logs are useful for characterizing sedimentary rocks and pore fluids in order to understand petroleum reservoirs.
This document provides information on formation evaluation from well logs, including determining porosity, permeability, water saturation, and identifying depleted gas reservoirs. It discusses:
1. Using density and neutron logs to determine porosity in gas-filled reservoirs, and relying on density logs for porosity in oil reservoirs due to clay effects.
2. Calculating water saturation using resistivity logs and accounting for formation water resistivity based on known water saturated zones.
3. Methods for estimating permeability, including using core data, pressure decline testing, porosity-permeability plots, and resistivity and SP logs.
4. Identifying depleted gas reservoirs by looking for large separation between density and neutron porosity logs,
This publication discusses use of quartz crystal microbalance in combination with the Knudsen Method for rapid determination of vapor pressure of low volatility compounds
1) The study compared initializing the RothC soil carbon model with measured vs. modelled carbon pools from grassland sites.
2) For most sites, initializing with measured vs. modelled pools produced similar projected changes in soil organic carbon from 2021-2060 under climate change scenarios.
3) For some sites, differences were found, likely due to differences in drainage affecting decomposition rates of resistant plant material not captured in the modelled pools.
Thermal models of Mercury's north polar region show that:
1) Spatially, regions of high radar backscatter match predictions of where water ice would be thermally stable.
2) MESSENGER measurements found bright surfaces in the coldest areas, and dark surfaces in warmer areas, where water ice would only be stable below ground.
3) The dark surface layer is proposed to be a lag deposit rich in impact-derived organics that has formed from subsurface water ice sublimation.
Thermal models of Mercury's north polar region show that spatially distributed regions of high radar backscatter match predictions of thermally stable water ice. MESSENGER measurements find bright surfaces in coldest areas where water ice is predicted to be stable, and dark surfaces in warmer areas where it is only stable below surface. The dark layer may be a sublimation lag deposit rich in impact-derived organic material. Water ice best explains Mercury's anomalous radar features based on thermal stability comparisons to other volatiles.
The document describes calculating the viscosity of a hydrous, leucogranitic melt using a regression model. It provides background on estimating magma viscosity and factors that influence it like temperature, water content, and crystal content. It then presents the problem of calculating the viscosity of a rhyolite magma at 900°C with 2% water and 0.03% crystal content. A plan is outlined to implement a VFT model to calculate melt viscosity and incorporate crystal content using an equation to find the final magma viscosity. A spreadsheet is presented carrying out these calculations.
This document summarizes modeling of low-temperature chemical alteration of martian basalt by water. Two scenarios were modeled: open system, where the system exchanges gases with the atmosphere; and closed system, sealed from the atmosphere. In the open system, alteration yields clays and carbonates, with near-neutral pH water. In the closed system, alteration yields clays and serpentine, with strongly alkaline water and reducing gases like H2 and CH4 forming at high pressures. The models provide insights into volatile storage during aqueous alteration on Mars' surface.
The document describes climate modeling experiments of Neoproterozoic conditions using an Earth system model. It explores scenarios ranging from a full "Snowball Earth" to a less severe "Slushball Earth" hypothesis. The model results support a Slushball scenario, with moderately cold global temperatures, ice-free ocean areas near the equator, and a functioning hydrological cycle. A Snowball scenario occurred only under extreme conditions. Higher atmospheric CO2 levels would be required to escape a full glaciation and avoid a "freeze-fry" super-greenhouse situation. Future studies should better model ocean currents and refine paleogeography and CO2 levels needed to melt a Snowball Earth.
This article discusses findings from the MESSENGER spacecraft revealing details about Mercury's dynamic atmosphere. The spacecraft found that Mercury's polar regions contain large amounts of water ice, fulfilling predictions. However, measurements also surprisingly showed that the laser altimeter detected very low reflectance of Mercury's surface in polar regions, indicating it is coated in a dark, absorbing material in addition to water ice. Further studies are needed to understand the nature and origin of this dark material.
Late Noachian Icy Highlands climate model: Exploring the possibility of trans...Sérgio Sacani
The nature of the Late Noachian climate of Mars remains one of the outstanding questions in the
study of the evolution of martian geology and climate. Despite abundant evidence for flowing water (valley
networks and open/closed basin lakes), climate models have had difficulties reproducing mean annual
surface temperatures (MAT) > 273 K in order to generate the “warm and wet” climate conditions presumed
to be necessary to explain the observed fluvial and lacustrine features. Here, we consider a “cold
and icy” climate scenario, characterized by MAT ∼225 K and snow and ice distributed in the southern
highlands, and ask: Does the formation of the fluvial and lacustrine features require continuous “warm
and wet” conditions, or could seasonal temperature variation in a “cold and icy” climate produce suffi-
cient summertime ice melting and surface runoff to account for the observed features? To address this
question, we employ the 3D Laboratoire de Météorologie Dynamique global climate model (LMD GCM) for
early Mars and (1) analyze peak annual temperature (PAT) maps to determine where on Mars temperatures
exceed freezing in the summer season, (2) produce temperature time series at three valley network
systems and compare the duration of the time during which temperatures exceed freezing with seasonal
temperature variations in the Antarctic McMurdo Dry Valleys (MDV) where similar fluvial and lacustrine
features are observed, and (3) perform a positive-degree-day analysis to determine the annual volume
of meltwater produced through this mechanism, estimate the necessary duration that this process must
repeat to produce sufficient meltwater for valley network formation, and estimate whether runoff rates
predicted by this mechanism are comparable to those required to form the observed geomorphology of
the valley networks.
Water ice is thought to be trapped in large permanently shadowed regions in the Moon’s polar regions, due to their extremely
low temperatures. Here, we show that many unmapped cold traps exist on small spatial scales, substantially augmenting the
areas where ice may accumulate. Using theoretical models and data from the Lunar Reconnaissance Orbiter, we estimate the
contribution of shadows on scales from 1 km to 1 cm, the smallest distance over which we find cold-trapping to be effective for
water ice. Approximately 10–20% of the permanent cold-trap area for water is found to be contained in these micro cold traps,
which are the most numerous cold traps on the Moon. Consideration of all spatial scales therefore substantially increases the
number of cold traps over previous estimates, for a total area of ~40,000 km2, about 60% of which is in the south. A majority of
cold traps for water ice is found at latitudes > 80° because permanent shadows equatorward of 80° are typically too warm to
support ice accumulation. Our results suggest that water trapped at the lunar poles may be more widely distributed and accessible
as a resource for future missions than previously thought.
1) Global climate models that include sophisticated cloud schemes show that tidally locked planets can develop thick water clouds near the substellar point due to strong convection. These clouds greatly increase the planetary albedo and stabilize temperatures, allowing habitability at twice the stellar flux previously thought possible.
2) The cloud feedback is stabilizing, as higher stellar flux produces stronger convection and higher albedos. Substellar clouds can block outgoing radiation, reducing the day-night temperature contrast.
3) Non-tidally locked planets do not experience this stabilizing cloud feedback, as clouds only form over parts of the tropics and mid-latitudes. Their albedo decreases with increasing stellar flux, producing a destabil
Creating Comfortable Air Conditions in Mars for a Sample Volume ShelterSamet Baykul
DATE: 2019.01
In this project, it is aimed to create a theoretical climate conditions for a sample volume room - shelter enough for 6 people to live inside. The shelter is designed to be as a cylinder shaped, which has the radius of 8m and 5m of height. The climate conditions inside the shelter is designed to be identical with earth conditions in comfort, which is 22°C and %50 relative humidity. The psychrometric processes and heat transfer phenomena is calculated and necessary operations are shown.
- Calculation of heat loss and humidity
- Literature survey for recent academic studies related topic
Snow precipitation on Mars driven by cloud-induced night-time convectionSérgio Sacani
Although it contains less water vapour than Earth’s atmosphere, the Martian atmosphere hosts clouds. These clouds,
composed of water-ice particles, influence the global transport of water vapour and the seasonal variations of ice deposits.
However, the influence of water-ice clouds on local weather is unclear: it is thought that Martian clouds are devoid of moist
convective motions, and snow precipitation occurs only by the slow sedimentation of individual particles. Here we present
numerical simulations of the meteorology in Martian cloudy regions that demonstrate that localized convective snowstorms
can occur on Mars. We show that such snowstorms—or ice microbursts—can explain deep night-time mixing layers detected
from orbit and precipitation signatures detected below water-ice clouds by the Phoenix lander. In our simulations, convective
snowstorms occur only during the Martian night, and result from atmospheric instability due to radiative cooling of water-ice
cloud particles. This triggers strong convective plumes within and below clouds, with fast snow precipitation resulting from
the vigorous descending currents. Night-time convection in Martian water-ice clouds and the associated snow precipitation
lead to transport of water both above and below the mixing layers, and thus would aect Mars’ water cycle past and present,
especially under the high-obliquity conditions associated with a more intense water cycle.
Monica Orellana is a senior scientist at the Institute for Systems Biology. Her paper was published in PNAS in August 2011. Title: Marine microgels as a source of cloud condensation nuclei in the high Arctic.
A recently formed ocean inside Saturn’s moon MimasSérgio Sacani
Moons potentially harbouring a global ocean are tending to become relatively common objects in the Solar System1. The presence of these long-lived global oceans is generally betrayed by surface modification owing to internal dynamics2. Hence, Mimas would be the most unlikely place to look for the presence of a global ocean3. Here, from detailed analysis of Mimas’s orbital motion based on Cassini data, with a particular focus on Mimas’s periapsis drift, we show that its heavily cratered icy shell hides a global ocean, at a depth of 20–30 kilometres. Eccentricity damping implies that the ocean is likely to be less than 25 million years old and still evolving. Our simulations show that the ocean–ice interface reached a depth of less than 30 kilometres only recently (less than 2–3 million years ago), a time span too short for signs of activity at Mimas’s surface to have appeared.
This document discusses restoring habitable conditions on Mars through planetary ecosynthesis or terraforming. It reviews the scientific feasibility and environmental ethics. Key points include:
- Mars was once warmer and had liquid water, but lost its atmosphere over time due to its small size. Warming Mars tens of degrees could make it habitable again within 100 years.
- Two alternative habitable states are possible: an oxygen-rich atmosphere like Earth, or a CO2 atmosphere with nitrogen and oxygen at lower levels. An oxygen-rich atmosphere would take over 100,000 years to produce.
- Processes that depleted Mars' early atmosphere included carbonate formation, loss to space from solar wind, and impacts removing atmosphere. Earth recy
1) Barnard 68 is considered a stable dense molecular cloud core, but observations indicate it should be gravitationally unstable and collapsing.
2) The authors argue Barnard 68 is experiencing a collision with another small core that will trigger its gravitational collapse within the next 200,000 years, forming a low-mass star.
3) Such core mergers may play an important role in triggering star formation and shaping properties of molecular cores and the stellar initial mass function.
A Subsurface Magma Ocean on Io: Exploring the Steady State of Partially Molte...Sérgio Sacani
Intense tidal heating within Io produces active volcanism on the surface, and its internal structure has long been a
subject of debate. A recent reanalysis of the Galileo magnetometer data suggested the presence of a high-meltfraction layer with >50 km thickness in the subsurface region of Io. Whether this layer is a “magmatic sponge”
with interconnected solid or a rheologically liquid “magma ocean” would alter the distribution of tidal heating
and would also influence the interpretation of various observations. To this end, we explore the steady state of a
magmatic sponge and estimate the amount of internal heating necessary to sustain such a layer with a high
degree of melting. Our results show that the rate of tidal dissipation within Io is insufficient to sustain a partialmelt layer of f > 0.2 for a wide range of parameters, suggesting that such a layer would swiftly separate into two
phases. Unless melt and/or solid viscosities are at the higher end of the estimated range, a magmatic sponge
would be unstable, and thus a high-melt-fraction layer suggested in Khurana et al. is likely to be a subsurface
magma ocean.
Water planets in_the_habitable_zone_atmospheric_chemistry_observable_features...Sérgio Sacani
This document discusses atmospheric models for water planets in the habitable zone. It begins by introducing water planets and noting that Kepler-62e and -62f are the first candidates for habitable zone water planets. It then outlines assumptions for atmospheric composition and cycling of gases like CO2 and CH4 through clathration in high-pressure water ice. Models suggest water planet atmospheres would be similar to terrestrial planets, with CO2 or H2O dominance depending on stellar flux. The habitable zone is only slightly different for water planets due to atmospheric albedo dominance. Kepler-62e and -62f are discussed as case studies for temperate water planets receiving fluxes of 1.2 and 0.41 times Earth's
Evidence for water_ice_near_mercury_north_pole_from_messenger _neutron_spectr...Sérgio Sacani
MESSENGER neutron spectrometer measurements show evidence for water ice near Mercury's north pole. Analysis of fast and epithermal neutron fluxes found a 1.1% decrease in fast neutrons and a 2.4% decrease in epithermal neutrons near the north pole compared to lower latitudes. This signal is consistent with a hydrogen-rich layer more than tens of centimeters thick beneath a surficial layer less than 25% water-equivalent hydrogen that is around 10-20 centimeters thick. The buried hydrogen-rich layer appears to be nearly pure water ice, and the total mass of water ice at Mercury's poles is estimated to be between 2×10^16 to 10^18 grams.
Evidence for water_ice_near_mercury_north_pole_from_messenger _neutron_spectr...
SJSU Poster Spring 2008 Rev3
1. Laboratory Measurements of Supersaturations Needed to Nucleate
Ice on Martian Dust Analogs in a Simulated Martian Atmosphere
Bruce D. Phebus1,2, Laura T. Iraci2, Anthony Colaprete2, Bradley M. Stone1
1 San Jose State University, San Jose, CA 95192; 2 NASA Ames Research Center, Moffett Field, CA 94035
___________~ Abstract ~___________ ___________~ Data ~___________ ___________~ Results ~___________
Water ice clouds play important roles in both the radiative balance and
........ Silicon Fit
the hydrologic cycle of Mars, and thus the predicted microphysical properties
3.5 _ _ _ Arizona Test Dust
of clouds can greatly affect models of the Mars climate system. Current ____ Clay
simulations rely on parameters that have not been measured for Martian 3.0 Clay Points
conditions.
Calculated (Pliq/Pice)
Saturation Ratio
We have measured the conditions necessary for ice nucleation on dust 2.5 Shet for traditional models
particles at Martian temperatures and water partial pressures. To do so, we
expose a dust sample to water vapor and cool it until ice is observed by
infrared spectroscopy. Our results show that ice nucleation requires much 2.0
greater supersaturation than estimated. Furthermore, we find a strong
temperature dependence which is not predicted by theory.
1.5
We have also observed uptake of water onto clay and Mars simulant
(JSC-1) particles. This observation, coupled with the high supersaturations 1.0
necessary to initiate ice, suggests that supercooled water could be stable Nucleation 155 160 165 170 175 180 185
under Martian atmospheric conditions. As a source of non-frozen, non-gas
phase water, this phenomenon could allow for liquid phase chemistry with Temperature of Nucleation [K]
water on Mars. Equilibrium
___________~ Conclusions ~___________
______~ Introduction to Mars ~______
• Critical saturation ratio needed for nucleation appears to be lower
• Pressure on Mars less than 1% that of Earth for smectite than for ATD
Figures Above show: Above Left shows IR spectra of a nucleation • Scrit is greater that that for traditional models
• Martian atmosphere primarily: ~ CO2 95%, N2 3%, Ar 1.6% experiment on smectite clay. P (H2O) = 5.3x10-6 Torr, T = 169 K,
• Scrit increases at lower temperatures
• The pressure on Mars varies: 3 to 6.5 torr saturation ratio = 1.3. The figure Above Right reports the conditions
for the experiment. Observe that nucleation occurs near 150 • Supercooled water could be present within orange triangles
• Two condensable components: CO2 and H2O (~0.03%) minutes, after which the temperature was adjusted to obtain • Models underestimate saturation ratios needed to nucleate water
• Temperatures for water ice clouds: 100 to 200 K (-173 to -73 °C) equilibrium monitored via the peak area. Steady adsorption of water
is observed leading up to nucleation; note absorbance feature in ice clouds
Reff: http://nssdc.gsfc.nasa.gov/planetary/factsheet/marsfact.html 05/01/2008
spectrum Min 142.5 for adsorbed water.
___________~ Implications ~___________
_________~ Experimental ~_________ Adsorption Desorption Figure to the
Left shows:
• Difficulty in nucleating water ice clouds maybe underestimated for
Adsorption &
Desorption of Martian conditions
Figures to Right: 7.0x10-4 torr
9.4x10-2 Pa H2O to JSC-1 • Preliminary modeling suggests drier atmosphere on Mars due to
A schematic of the T = 197.5 K 1.4x10-6 torr Mars Simulant nucleation effects
experiment. RH = 85% 2.3x10-4 Pa
Pressure is held T = 180.6 K • Possible net adsorption of water on lofted dust over many day/night
RH = 4%
constant against continuous cycles
pumping. Cold finger is jacketed
to prevent cold spots. ___________~ Future Work ~___________
Saturation Ratio Defined • Nucleation Conditions for JSC-1 Mars Simulant
The saturation ratio is calculated by dividing the P _________~ Acknowledgements~________
observed pressure by the vapor pressure at the S = obs • Growth Rates for Ice on JSC-1 Mars Simulant, Arizona Test Dust,
observed temperature. VPice Emmett Quigley, Dave Scimeca, Ted Roush
Smectite Clay and Silicon
NASA Planetary Atmospheres Program, Philippe Crane
San Jose State Foundation
Mars Pictures Courtesy NASA/JPL-Caltech