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A significant step in space exploration during the 21st century will be human settlement on Mars. Instead of transporting all the construction materials from Earth to the red planet with incredibly high cost, using Martian soil to construct…
We use a 3D general circulation model to compare the primitive Martian hydrological cycle in "warm and wet" and "cold and icy" scenarios. In the warm and wet scenario, an anomalously high solar flux or intense greenhouse warming…
The abundance of highly siderophile elements (HSEs) inferred for Mars' mantle from martian meteorites implies a Late Veneer (LV) mass addition of ~0.8 wt% with broadly chondritic composition. Late accretion to Mars by a differentiated…
MESSENGER observations suggest a magma ocean formed on proto-Mercury, during which evaporation of metals and outgassing of C- and H-bearing volatiles produced an early atmosphere. Atmospheric escape subsequently occurred by plasma heating,…
Lithium is overabundant in cosmic rays because protons impact on carbon and oxygen nuclei and fission them. Among the products of this fission is lithium. Given this preference for carbon and oxygen atoms, in this work I propose that in an…
Previous studies that have considered the ocean circulation on Enceladus have generally assumed the salinity to be Earth-like. However, according to observations and geochemical constraints, the salinity of Enceladus' ocean is likely to be…
Comparing compositional models of the terrestrial planets provides insights into physicochemical processes that produced planet-scale similarities and differences. The widely accepted compositional model for Mars assumes Mn and more…
$\text{CO}_{\text{2}}$ ice clouds are important for polar energy balance and the carbon dioxide cycle on Mars. However, uncertainties remain regarding their physical and radiative properties, which control how polar $\text{CO}_{\text{2}}$…
Seismic anisotropy, arising from the crystallographic or lattice-preferred orientation of anisotropic minerals or the shape-preferred orientation of melts or cracks, can establish a critical link between Mars's past evolution and its…
With approximately one ninth of Earth's mass, Mars is widely considered to be a stranded planetary embryo that never became a fully-grown planet. A currently popular planet formation theory predicts that Mars formed near Earth and Venus and…
Water vapour atmospheres with content equivalent to the Earth's oceans, resulting from impacts or a high insolation, were found to yield a surface magma ocean. This was, however, a consequence of assuming a fully convective structure. Here…
Observations of JWST have revealed that several close-in exoplanets have sulfur-rich atmospheres through SO$_2$ detections. Atmospheric sulfur is often thought to originate from solid accretion during planet formation, whereas recent…
We propose a mechanism for the oxidation of gaseous CO into CO2 occurring on the surface mineral hematite (Fe2O3(s)) in hot, CO2-rich planetary atmospheres, such as Venus. This mechanism is likely to constitute an important source of…
The distribution of subsurface water ice on Mars is a key constraint on past climate, while the volumetric concentration of buried ice (pore-filling versus excess) provides information about the process that led to its deposition. We…
Terrestrial planets, with silicate mantles and metallic cores, are likely to obtain water and carbon compounds during accretion. Here I examine the conditions that allow early formation of a surface water ocean (simultaneous with cooling to…
Microscopic liquid brines, especially calcium-perchlorate could emerge by deliquescence on Mars during night time hours. Using climate model computations and orbital humidity observations, the ideal periods and their annual plus daily…
CaSO4 minerals (i.e. gypsum, anhydrite and bassanite) are widespread in natural and industrial environments. During the last several years, a number of studies have revealed that nucleation in the CaSO4-H2O system is non-classical, where…
The absence of global magnetic fields is often cited to explain why Mars lacks a dense atmosphere. This line of thought is based on a prevailing theory that magnetic fields can shield the atmosphere from solar wind erosion. However, we…
Models of the Sun's long-term evolution suggest that its luminosity was substantially reduced 2-4 billion years ago, which is inconsistent with substantial evidence for warm and wet conditions in the geological records of both ancient Earth…
The presence of the ancient valley networks on Mars indicates that the climate at 3.8 Ga was warm enough to allow substantial liquid water to flow on the martian surface for extended periods of time. However, the mechanism for producing…