graphite Archives

A schematic representation of the scenario we propose here for clean high-yield production of prebiotic feedstock. Events move around from top left clockwise: first Earth has a neutral atmosphere; this is reduced following giant impact at 4.3 Ga by oxidation of the impactor’s metal core to produce a massive H2 atmosphere with significant methane and ammonia; This atmosphere quickly cools (in < 1 kyr) with photochemistry producing a tholin-rich haze that deposits complex nitrogen-rich organics; these organics become progressively buried and graphitized by interaction with magma, the atmosphere clears as H2 is lost to space and becomes neutral again; finally, magmatic gases interact with the graphite, and are scrubbed to produce high yields of clean HCN, HC3N and isonitriles. -- astro-ph.EP

Astrogeology, Atmospheres, Climate, Weather, Biochemistry & Organic Chemistry, Biogeochemical Cycles & Geobiology, Caves, Craters, Mountains, Subsurface, Lava Tubes, Extremeophiles and Extreme Environments, Habitable Zones, Impact events, Origin & Evolution of Life, Status Report

A Surface Hydrothermal Source of Nitriles and Isonitriles

by Keith CowingMarch 24, 2024March 24, 2024

Giant impacts can generate transient hydrogen-rich atmospheres, reducing atmospheric carbon. The reduced carbon will form hazes that rain out onto the surface and can become incorporated into the crust. Once […]

The Caloris basin on Mercury, which is 1525 kilometers in diameter, in an enhanced-color composite image. The interior of Caloris has been flooded by lava, which here appears orange. Post-flooding impact craters have exposed the subsurface, with the largest excavating the low-reflectance material (LRM), which appears dark blue. Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington.

Astrochemistry, Astrogeology, Biosignatures & Paleobiology, Imaging & Spectroscopy, Mercury, Status Report

First Observationally-Constrained Estimates Of Carbon In Mercury’s Near Surface

by Keith CowingJune 15, 2023June 15, 2023

A striking feature of the surface of Mercury is the low-reflectance material (LRM), areas exhibiting 20-30% lower average reflectance that are often associated with impact craters, especially the ejecta and […]