Impact event Archives - Page 6 of 24 - Astrobiology

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). […]

New Fossils From Earth’s Most Famous Extinction

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 on a 3 Gyr-old Earth-sized planet with a small core Rc = 0.2R and L = 25 km (a) and 100 km (b). In each panel, the left half displays the melt fraction and the right half the melting mechanism, with the materials shown at their pre-impact positions. Basaltic crust is shown in light gray and dunitic mantle material in medium-shaded gray. The melt generation farther than 5L from the center of the melt region below the impact point (approximated by z = L) is neglected. -- astro-ph.EP

Astrogeology, Biogeochemical Cycles & Geobiology, Caves, Craters, Mountains, Subsurface, Lava Tubes, Exoplanets, -moons, -comets, Gaia - Planetary Perspectives, Impact events, Mapping, Geodesy, Cartography, Bathymetry, Status Report

The Influence Of Interior Structure And Thermal State On Impact Melt Generation Upon Large Impacts Onto Terrestrial Planets

by Keith CowingJune 25, 2025June 25, 2025

We investigate the melt production of planetary impacts as a function of planet size (R/REarth=0.1-1.5), impactor size (L=1-1000 km), and core size ratio (Rcore/R=0.2-0.8) using a combination of parameterized convection […]

Shifting distributions of genera within functional groups and their phylogenetic underpinnings among the end-Cretaceous, survival pool, and Recent biotas. (A) Changes in absolute richness of genera within functional groups between the end-Cretaceous biota, the survivor pool, and today. Warmer colors indicate higher genus richness. Mixing of the color gradient in the survivor pool and Recent biota indicates shifts in the richness rank order of functional groups. (B) Phylogenetic underpinnings of functional group composition for the end-Cretaceous and Recent biotas. The proportion of genera in a functional group per family is reflected by the widths of ribbons connecting the tips of the family-level phylogeny to functional groups. The middle panel shows the proportional changes in genus richness of functional groups among taxon sets. The connections between the taxon sets are to visualize shifts in the rank order of functional groups and do not imply smooth transitions between them. -- Science Advances

Atmospheres, Climate, Weather, Biogeochemical Cycles & Geobiology, Extinction events, Fossils & Paleontology, Gaia - Planetary Perspectives, Habitable Zones, Impact events, Mapping, Geodesy, Cartography, Bathymetry, Origin & Evolution of Life, Press Release, Water/Hycean Worlds & Oceanography

How Does Life Rebound From Mass Extinctions?

by Keith CowingJune 4, 2025June 4, 2025

If you’re an animal living through a mass extinction, it’s best to be one that’s found a unique way to make a living.

Evolution of the number of planets in one system averaged over 20 runs, ⟨Np⟩. The horizontal axes are the time normalized by the Kepler period of the innermost planet in each model. (a) model R1 (0.05–0.15au) and (b) model R3 (0.5–1.5au). -- astro-ph.EP

Astrogeology, Exoplanets, -moons, -comets, Impact events, Status Report

Semi-analytical Model For The Dynamical Evolution Of Planetary Systems via Giant Impacts

by Keith CowingMay 28, 2025May 28, 2025

In the standard model of terrestrial planet formation, planets are formed through giant impacts of planetary embryos after the dispersal of the protoplanetary gas disc.

Giant impacts are highly complex events with different processes dominating the dynamics of different regions of the colliding bodies. Illustrative time snapshots from an example SPH giant impact simulation with a resolution on the order 106 particles. All particles in the lower hemispheres only of the colliding bodies are shown and coloured by material type as follows: target core (grey), mantle (orange), and atmosphere (blue); impactor core (brown) and mantle (yellow). Colour luminosity is scaled by the particles’ internal energy. Impact parameters (defined in Section 2.2) and atmospheric loss fraction (Xatm) are detailed in the first panel, with lost particles (those that ultimately become unbound to the largest remnant) coloured in green. The simulation time corresponding to each snapshot is given in each panel, with t = 0.0 hr defined as the point of impact. White dashed lines in the second and third panels indicate the approximate location of the front of the impact shock wave. An animation of this figure is available in the Supplementary Material. -- astro-ph.EP

Atmospheres, Climate, Weather, Biogeochemical Cycles & Geobiology, Exoplanets, -moons, -comets, Impact events, Status Report

Atmospheric Loss During Giant Impacts: Mechanisms And Scaling Of Near- And Far-field Loss

by Keith CowingMay 14, 2025May 14, 2025

The primary epoch of planetary accretion concludes with giant impacts – highly energetic collisions between proto-planets that can play a key role in shaping a planet’s inventory of volatile elements. […]

A, C 3D view of the sheet unit overlying the fragmented breccia unit at the eastern rim of the Ritchey crater, HiRISE image on HRSC DEM (architected from Fig. 1C, D). B, D The impactite stratigraphy at Aumühle outcrop, Ries crater (B, Germany) and Mistastin lake impact structure (D, Canada). Photo D by Cassandra Marion in 2021 at Coté Creek (https://craterexplorer.ca/mistastin-impact-crater/). -- Nature Communications via PubMed

Astrogeology, Biogeochemical Cycles & Geobiology, Biosignatures & Paleobiology, Caves, Craters, Mountains, Subsurface, Lava Tubes, Habitable Zones, Icy Worlds, Impact events, Mars, Meteorites & Asteroids, Status Report

Hydrothermal Activity Generated By Impact Melt Emplacement On The Rim Of Ritchey Crater, Mars

by Keith CowingMay 3, 2025May 3, 2025

Impact-induced hydrothermal systems have the potential to sustain long-lived aqueous environments throughout the history of Mars, yet their nature and distribution are not well-understood.