(A) Map of the study area on Axel Heiberg Island, Nunavut, Canada. The north arrow is valid for every panel. (B) Geological map of the region modified from Harrison and Jackson (2010) with the sampling sites (yellow dots) selected for the study grouped by sector. CR: Colour ridge, WG: White glacier, GH: Gypsum Hill. The ArcticDEM was used to highlight the topography of the area. (C) Sampling sites (yellow dots) with ESRI imagery used as a basemap. The scale is the same as in panel b. (For interpretation of the references to color in this figure legend, the reader is referred to the Web version of this article.) -- Science Direct

Analog Studies, Arctic / Antarctic / Alpine, Astrogeology, Away Teams & Field Reports, Biochemistry & Organic Chemistry, Biogeochemical Cycles & Geobiology, Biophysics, Biosignatures & Paleobiology, Habitable Zones, Icy Worlds, Imaging & Spectroscopy, Impact events, Mapping, Geodesy, Cartography, Bathymetry, Microbiology & Virology, Polar / Alpine Expeditions, Sample Return, Status Report

Mineralogy, Geochemistry And Morphology Of Arctic Gossans On Axel Heiberg Island, NU, Canada: Spectroscopic Investigation And Implications For Mars

by Keith CowingAugust 2, 2025August 2, 2025

Gossans are formed through the oxidation of sulfide ore deposits by fluids, such as meteoric water or hydrothermal solutions, leading to locally acidic conditions.

Time evolution of mole fractions of organic molecules. The molecules represented by each chemical formula are as follows: hydrogen cyanide (HCN), formaldehyde (CH2O), methanol (CH3OH), formic acid (HCOOH), isocyanic acid (HNCO), methanimine (CH2NH), ethanimine (CH3CHNH), N-methylmethanimine (CH3NCH2), acetaldehyde (CH3CHO), acetonitrile (CH3CN), formamide (NH2CHO), formyl cyanide (CHOCN), ethane (C2H6 ), propane (C3H8 ). Molecules considered particularly important for biomolecule synthesis (see Section 3.2.2) are indicated with bold lines. -- astro-ph.EP

Astrogeology, Biochemistry & Organic Chemistry, Biogeochemical Cycles & Geobiology, Biosignatures & Paleobiology, Comets and Asteroids, Exoplanets, -moons, -comets, Imaging & Spectroscopy, Impact events, Status Report

Exploring Impact Vapor Plume Reactions from Asteroidal Impacts: Monte Carlo Simulations and Implications for Biomolecules Synthesis

by Keith CowingAugust 2, 2025

During a hypervelocity impact, both the impactor and target materials evaporate, generating an impact vapor plume with temperatures reaching several thousand K.

Analog Studies, Atmospheres, Climate, Weather, Comets and Asteroids, Exoplanets, -moons, -comets, Habitable Zones, Impact events, Status Report

The Response of Planetary Atmospheres To The Impact Of Icy Comets II: Exo-Earth Analogues

by Keith CowingJuly 25, 2025July 25, 2025

The orbital regime of a terrestrial planet plays a significant role in shaping its atmospheric dynamics, climate, and hence potential habitability.

The result of 100 successful simulations of the back20 model (the ring at 0.85 au with a 20% background) that produced a good match to all terrestrial planets (as defined in Section 3.1). The black dots show the results of individual simulations with good final planets. The bigger red dots are the real planets. Note that we do not exclude simulations that produced additional bodies with m < 0.05 MEarth in the Mars region (1.2 < a < 1.8 au). Some of these bodies would collide with Mars at t > 200 Myr (these simulations were terminated at 200 Myr). -- astro-ph.EP

Astrogeology, Biogeochemical Cycles & Geobiology, Exoplanets, -moons, -comets, Impact events, Status Report

Terrestrial Planet Formation From Two Source Reservoirs

by Keith CowingJuly 22, 2025July 22, 2025

This work describes new dynamical simulations of terrestrial planet formation. The simulations started at the protoplanetary disk stage, when planetesimals formed and accreted into protoplanets, and continued past the late […]

Conceptualization of Nankoweap landslide that brought down large boulders of Kaibab Limestone from the cliffs at left and created a geologically short-lived paleolake in Grand Canyon. Credit Karl Karlstrom

Astrogeology, Atmospheres, Climate, Weather, Caves, Craters, Mountains, Subsurface, Lava Tubes, Impact events, Meteorites & Asteroids, Press Release

Link Established Between A Grand Canyon Landslide And The Meteor Crater Impact Event

by Keith CowingJuly 16, 2025July 16, 2025

Geology is full of detective stories about Earth’s history, and a new paper in Geology by University of New Mexico Distinguished Professors Emeritus Karl Karlstrom and Laurie Crossey, along with […]

Schematic depiction of a bow shock flow. Meteoroid entry results in the bow shock wave (red line). The box illustrates stream lines around the object. Heated medium due to the bow shock immediately cools down with expansion process. Turbulent flow happens at the tail region through a growth of an instability, leading to mixing of material ablated from the projectile with the atmosphere. -- astro-ph.EP

Astrochemistry, Atmospheres, Climate, Weather, Impact events, Meteorites & Asteroids, Status Report, Titan

Modeling Atmospheric Alteration on Titan: Hydrodynamics and Shock-Induced Chemistry of Meteoroid Entry

by Keith CowingJuly 16, 2025July 16, 2025

Meteoroid entry into planetary atmospheres generates bow shocks, resulting in high-temperature gas conditions that drive chemical reactions.

The peak temperature achieved by all tracer particles in simulations of a 1 km diameter comet impacting at 10 km s−1 (left) and 40 km s−1 (right) in a provenance plot, where the tracers are shown at their initial locations prior to the impact. A solid black line is shown between the two halves of the figure to delineate the difference between the two simulations. The 10 km s−1 impact on the left shows a peak temperature of ∼ 8900 K, whereas the 40 km s−1 impact on the right achieves a peak temperature of ∼ 74 000 K. Although the range of temperatures achieved during the two impacts is vastly different, the distribution of temperatures is similar, with a sharp increase in temperatures at the leading edge and raised temperatures towards the centre of the body. -- astro-ph.EP

Astrochemistry, Astrogeology, Biochemistry & Organic Chemistry, Biosignatures & Paleobiology, Comets and Asteroids, Impact events, Status Report

Constraining The Survival Of HCN During Cometary Impacts

by Keith CowingJuly 14, 2025July 14, 2025

Cometary impacts have been invoked as an atmosphere-independent method of stockpiling hydrogen cyanide (HCN), a key prebiotic feedstock molecule, into environments favourable for the onset of prebiotic chemistry on the […]

Eccentricity and position snapshots over time of a simulation using the mixed scenario where all 4 terrestrial planets fit constraints and the Earth analogue had a final CC embryo impact. Snapshots are shown over time, including the moment after the final giant impact. The initial NC embryos and planetesimals are shown with the embryos in black and the planetesimals in orange, as well as the CC embryos and planetesimals in blue with Jupiter and Saturn in black on the far right. The final snapshot is the real solar system. -- astro-ph.EP

Atmospheres, Climate, Weather, Biogeochemical Cycles & Geobiology, Extinction events, Impact events, Mars, Mercury, Moon, Status Report, Venus

Dynamical Origin Of Theia, The Last Giant Impactor On Earth

by Keith CowingJuly 4, 2025July 4, 2025

Cosmochemical studies have proposed that Earth accreted roughly 5-10% of its mass from carbonaceous (CC) material, with a large fraction delivered late via its final impactor, Theia (the Moon-forming impactor). […]

Atmospheres, Climate, Weather, Biosignatures & Paleobiology, Extinction events, Fossils & Paleontology, Gaia - Planetary Perspectives, Impact events, Meteorites & Asteroids, Press Release

New Fossils From Earth’s Most Famous Extinction Show Climate Tipping Point Was Crossed

by Keith CowingJuly 4, 2025July 4, 2025

The collapse of tropical forests during Earth’s most catastrophic extinction event was the primary cause of the prolonged global warming which followed, according to new research.

Scheme of a geothermal valley between two snow-covered Hadean volcanoes. The fumaroles, thermal springs, apron pools, and terracettes are shown based on the reconstruction of the 3.48 Ga old Hadean geothermal system. On the right, various reactions of CO2 sequestration in a Hadean volcanic system are indicated, see Section 3.2.5 and Section 3.2.6. Inserts: (A) volcanic fumaroles, image from https://home.nps.gov/articles/000/fumaroles.htm, credit: USGS. (B) Schematic cross section of a pH-neutral hot spring, redrawn with modifications from [341,342]. (C) White Terraces of New Zealand as an example of volcanic terracettes (painted by Charles Bloomfield in 1884, two years before the terraces were buried under the waters of the lake Rotomahana following the eruption of Mt. Tarawera. Image credit: Museum of New Zeeland, https://collections.tepapa.govt.nz/object/42254, accessed on 23 December 2024.). (D) Interconversion of nitriles, amides, and ammonium salts of organic acids, represented by their simplest species, in geothermal pools in the presence of inorganic catalysts; each of the nitrogen-containing compounds shown is considered as a substrate for further synthetic reactions. Formamide and other amides, as the least volatile components, may have sustained/buffered the whole system. -- Life via PubMed

Astrogeology, Biochemistry & Organic Chemistry, Biogeochemical Cycles & Geobiology, Biophysics, Biosignatures & Paleobiology, Caves, Craters, Mountains, Subsurface, Lava Tubes, Extinction events, Fossils & Paleontology, Genomics, Proteomics, Bioinformatics, Habitable Zones, Impact events, Moon, Origin & Evolution of Life, Status Report

Origin Of The RNA World In Cold Hadean Geothermal Fields Enriched In Zinc And Potassium – Abiogenesis As A Positive Fallout From The Moon-Forming Impact?

by Keith CowingJuly 1, 2025July 1, 2025

The ubiquitous, evolutionarily oldest RNAs and proteins exclusively use rather rare zinc as transition metal cofactor and potassium as alkali metal cofactor, which implies their abundance in the habitats of […]

Impact events

Mineralogy, Geochemistry And Morphology Of Arctic Gossans On Axel Heiberg Island, NU, Canada: Spectroscopic Investigation And Implications For Mars

Exploring Impact Vapor Plume Reactions from Asteroidal Impacts: Monte Carlo Simulations and Implications for Biomolecules Synthesis

The Response of Planetary Atmospheres To The Impact Of Icy Comets II: Exo-Earth Analogues

Terrestrial Planet Formation From Two Source Reservoirs

Link Established Between A Grand Canyon Landslide And The Meteor Crater Impact Event

Modeling Atmospheric Alteration on Titan: Hydrodynamics and Shock-Induced Chemistry of Meteoroid Entry

Constraining The Survival Of HCN During Cometary Impacts

Dynamical Origin Of Theia, The Last Giant Impactor On Earth

New Fossils From Earth’s Most Famous Extinction Show Climate Tipping Point Was Crossed

Origin Of The RNA World In Cold Hadean Geothermal Fields Enriched In Zinc And Potassium – Abiogenesis As A Positive Fallout From The Moon-Forming Impact?

Potential Survivable Niches For Microbial Life On The Lunar South Pole

JWST Telemetry Combined With Active Coronagraphy: Raw Contrast Predictions For Exoplanet Imaging With The Habitable Worlds Observatory

Antarctica Is Home To Microbes Found Nowhere Else On Earth

Study: Peptides Can Form Well-defined Structures In Harsh, Venus-like Conditions

Modeling Carbon-Based Planets with MAGRATHEA

European Astronomical Society Annual Meeting 2027

2027 Sagan Summer Workshop Exoplanet Masses: In the Era of Gaia and Extreme Precision Radial Velocities