astrogeology Archives

Atmosphere loss of Barnard’s Star planets, under various assumptions of planet masses, bulk densities, and initial atmospheric mass fraction. The mass range tested for a given planet is between its minimum mass (based on RV data; B25) and 2.5 times the minimum mass (see Section 2). The bulk densities ρ, used to calculate planet radius in the evolution models, span a liberal range: the Solar system rocky planets have densities between 3.93 g cm−3 (Mars) and 5.51 g cm−3 (Earth). No matter what assumptions are made, the planets are completely stripped of their atmospheres within 2 Gyr. The atmospheres survive longer if the planets are more massive, denser, farther from the star, and begin with a larger atmospheric mass fraction. - MNRAS

Planets Orbiting Barnard’s Star Seem To Be Small, Strange, And Utterly Uninhabitable

by Keith CowingJuly 16, 2026July 16, 2026

[University of Cambridge] Scientists have painted the most detailed portrait yet of the planetary system orbiting Barnard’s Star – the Sun’s closest neighbour after Alpha Centauri, just under six light-years […]

NASA’s Perseverance took this selfie at “Witch Hazel Hill” on Jezero Crater’s rim on May 10, 2025. The small dark hole in the rock in front of the rover is the borehole made when the rover collected the “Bell Island” sample. The small puff of dust left of center and below the horizon line is a dust devil. Credit: NASA/JPL-Caltech/MSSS larger image

Mars

Perseverance Rover Provides A Record of Ancient Mars Impacts

by Keith CowingJuly 16, 2026July 16, 2026

[NASA] Old rocks exposed on the rim of Jezero Crater preserve a roughly 4-billion-year-old cosmic “weather report” from the solar system’s most dynamic era.

The New jersey meteorite -- [SETI Institute]

Astrochemistry

Alien World Chemistry Found Inside A Meteorite that Struck A New Jersey Home

by Keith CowingJuly 15, 2026July 15, 2026

[SETI Institute] On July 16, 2024 a daytime meteor shook New York City with a sonic boom as it passed just south of the Statue of Liberty. Now, an international […]

The diverging paths of iron (Fe) and nickel (Ni) from minerals to proteins. Fe-based metabolisms flourish both before and after Earth’s oxygenation. Ni-based metabolisms are almost exclusively anaerobic, reflecting their origin in the reducing Archean. Fe is used by biology as a generalist, due to its flexibility, which can be seen both in its diverse mineral chemistry and in metal-binding centers of proteins. Ni is less flexible mineralogically, chemically in proteins, and more evolutionarily constrained, as reflected by its metabolic exclusion from oxidized environments. -- LIFE

Astrogeology

Diverging Mineral Chemistry of Iron and Nickel Throughout Earth’s Changing Redox Conditions Reveals Foundation for Their Evolution as Protein Cofactors

by Keith CowingJuly 14, 2026July 14, 2026

[LIFE] Iron (Fe) and nickel (Ni) were both foundational to early metabolism, yet their biological trajectories diverged as Earth’s surface redox state changed. Here, we integrate mineral chemistry network analysis, […]

Potential environments for the origin of life and the corresponding roles of minerals. (a) In the deep-sea hydrothermal vent hypothesis, metal sulfides play a critical role in the formation of chemical precursors and building blocks. (b) In terrestrial hot spring, minerals may concentrate and stabilize molecular building blocks, catalyze polymerization under wet–dry cycling conditions, and provide protection against environmental stresses. (c) Extraterrestrial input of organic matter through meteorites, comets and IDPs. Minerals are the carrier and preserver of organic compounds and may possibly take part in the prebiotic synthesis of organic compounds in extraterrestrial environments. (Background images are modified based on AI-generated illustrations.) -- [Fundamental Research]

Origin & Evolution of Life

The Role Of Minerals In Prebiotic Evolution: Implications For Identifying Worlds With The Potential For Life’s Origin

by Keith CowingJuly 12, 2026July 12, 2026

[Fundamental Research] Understanding the origin of life requires explaining how abiotic molecules transitioned into the first living systems within plausible geological settings. Increasing evidence suggests minerals as active participants in […]

An SwRI-led study modeled the concentration

Astrogeology

SwRI Study Found Primordial Mini-moons May Explain Meteorite Composition

by Keith CowingJuly 10, 2026July 23, 2026

[SwRI] A new Southwest Research Institute-led study proposes a solution to a long-standing puzzle in planetary science — what caused the concentration, assembly and preservation of millimeter-sized, spherical mineral grains […]

Schematic showing the thermal and atmospheric escape evolution of two interpretations of sub-Neptune interiors. In a standard planetary model, a silicate interior is distinct from a hydrogen-rich envelope. As the planet contracts, hydrogen is removed from the upper atmosphere via stellar heating, and the interior-envelope boundary does not significantly contract with time. The temperature at this interface can reach of order ∼ 10, 000 K at early ages. In the miscible model, the interior-envelope boundary is defined by a binodal surface, which delineates regions in which hydrogen and silicate are miscible or immiscible. The temperature at the binodal surface does not change significantly with time. The radial position of the binodal surface contracts with time, exsolving hydrogen into the base of the envelope, while hydrogen is also removed from the top of the upper atmosphere.-- [astro-ph.EP]

Exoplanets, -moons, -comets

Testing The Prevalence Of Hydrogen-silicate Miscibility In Young Sub-Neptunes

by Keith CowingJuly 10, 2026July 10, 2026

[astro-ph.EP] Hydrogen-silicate miscibility can significantly alter the interior structure and thermal evolution of sub-Neptunes. We consider the interplay between this miscibility and stellar-driven atmospheric escape.

An example of variolitic pillow lavas in the Whundo Group. The black spots are a feature known as varioles, which form in water-rich lavas Credit Adelaide University

Astrogeology

Ancient Rocks Reveal How Water Shaped Earth 3.1 Billion Years Ago

by Keith CowingJuly 10, 2026July 10, 2026

[Adelaide University] Geologists studying some of the planet’s oldest volcanic rocks have uncovered new evidence that water was playing a major role in shaping Earth’s interior and driving volcanic activity […]

Mars

Water Ice Inside A Martian Crater

by Keith CowingJuly 9, 2026July 9, 2026

[ESA] Like a sprinkle of powdered sugar on a rich red velvet cake, this scene from the ESA/Roscosmos ExoMars Trace Gas Orbiter captures the contrasting colours of bright white water-ice […]

Proposed conceptual model of hematite formation and evolution in Gale crater.

Mars

Hematite Is A Mineralogical Marker Of Ancient Climate Change On Mars

by Keith CowingJuly 9, 2026July 9, 2026

[Science via PubMed] The ancient climate of Mars changed from warm to cold surface conditions. This climate transition is demonstrated by geomorphological evidence but lacks suitable mineralogical indicators.