Meteorites & Asteroids Archives

Illustrations of magnetotactic bacteria (MTB) under electron microscopes, and MTB from extreme environments on Earth and putatively ancient Mars. A The scanning electron micrograph and (B, C) transmission electron micrographs of MTB. White arrows indicate magnetosome chains, and white triangles indicate granules. D Terrestrial extremotolerant MTB and implications for ancient Mars. MTB are found to be able to resist various hostile settings, such as irradiation, hypomagnetic exposure, microgravity, metal stress, hypersalinity, acidic/hyperalkaline pH, and freezing/moderately hyperthermal temperatures. MTB emerged early in Earth’s history. Since ancient Mars was also characterized by many MTB-favorable aquatic/sediment oxic-anoxic conditions and a global magnetic field, it is proposed that Mars may have harbored MTB-like life in the past. -- ISME

Biophysics, Biosignatures & Paleobiology, Fossils & Paleontology, Mars, Meteorites & Asteroids, Microbiology & Virology, Status Report

Renaissance For Magnetotactic Bacteria In Astrobiology

by Keith CowingNovember 29, 2023November 29, 2023

Capable of forming magnetofossils similar to some magnetite nanocrystals observed in the Martian meteorite ALH84001, magnetotactic bacteria (MTB) once occupied a special position in the field of astrobiology during the […]

Reaction of choline chloride with IPF solution in UAFW (Reaction sample CH-UAFW-5). -- Life

Astrochemistry, Biochemistry & Organic Chemistry, Biosignatures & Paleobiology, Genomics, Proteomics, Bioinformatics, Meteorites & Asteroids, Origin & Evolution of Life, Panspermia, Status Report

Prebiotic Syntheses of Organophosphorus Compounds from Reduced Source of Phosphorus in Non-Aqueous Solvents

by Keith CowingNovember 26, 2023November 26, 2023

Reduced-oxidation-state phosphorus (reduced P, hereafter) compounds were likely available on the early Earth via meteorites or through various geologic processes.

Flowchart of the procedure used for Lu-Hf analysis of extraterrestrial zircons. 1. The zircons are thermally annealed and then subjected to chemical abrasion2, 69. Two leachates (L1 and L2) and one residue (R) solutions are retrieved for further processing. The solutions are passed on chromatography columns filled with AG1-X8 resin to separate U+Pb from a solution containing Lu, Hf, Zr, and other trace elements. The U+Pb elutions are analyzed using a Phoenix TIMS at Princeton University. The solution containing Lu, Hf, Zr, and other trace elements is split into two, with 30% used for Lu/Hf determination using an iCAP at Princeton University, and 70% used for Hf purification and Hf isotopic analysis at the Origins Lab of the University of Chicago. 2. The "Lu, Hf, Zr" 70% split solution is passed on a column filled with TODGA resin 52, 53 to separate Zr+Hf from most other elements. 3. The Zr+Hf cut is passed on a second column filled with LnSpec resin (Fig. 2) to separate Hf from Zr 27, 50. 4. The isotopic composition of purified Hf is analyzed with a Neptune MC-ICP-MS at the University of Chicago. -- astro-ph.EP

Astrochemistry, Astrogeology, Mars, Meteorites & Asteroids, Moon, Status Report

Methodologies for 176Lu-176Hf Analysis of Zircon Grains from the Moon and Beyond

by Keith CowingNovember 25, 2023

Zircons are found in extraterrestrial rocks from the Moon, Mars, and some differentiated meteorite parent-bodies. These zircons are rare, often of small size, and have been affected by neutron capture […]

Left: This image shows an oblique view of the Aswan collapse site. Five months after the collapse it clearly stands out as a substantially brighter region. The normal albedo is 0.17 ± 0.01 (Pajola et al. 2017a) and the current modelling suggests that dust and water ice near the intrinsic nucleus mixing ratio was exposed at this time (but no CO2 ice). Image MTP024 / n20151226t170504370id4df22.img (Sierks & the OSIRIS Team 2018b) was acquired on 2015 December 26 with ∼ 1.4 m px−1 resolution when Rosetta was 77.0 km from the comet. Right: This is a face–on view of the cliff showing that the brightness of the scar is significantly reduced, yet somewhat higher than for the surroundings eleven months after collapse. At this point the current modelling suggests a ∼ 0.5 mm dust mantle, i. e., so thin that some reflection of the water ice still might reach the surface. Image MTP030 / n20160608t143426745id4df22.img (Sierks & the OSIRIS Team 2018c) was acquired on 2016 June 8 with ∼ 0.5 m px−1 resolution when Rosetta was 29.7 km from the comet. -- astro-ph.EP

Astrochemistry, Astrogeology, Comets and Asteroids, Icy Worlds, Meteorites & Asteroids, Status Report

Cliff Collapse On Comet 67P/Churyumov-Gerasimenko – I. Aswan

by Keith CowingNovember 25, 2023November 25, 2023

The Aswan cliff on Comet 67P/Churyumov-Gerasimenko collapsed on 2015 July 10. Thereby, relatively pristine comet material from a depth of ~12 m was exposed at the surface. Observations of the […]

Confocal fluorescence microscopy images (1000 · ) of halite crystal-embedded cells of Deinococcus radiodurans co-stained with SYTO 9 and PI, showing characteristics of the crystal, the distribution of microorganisms inside fluid inclusions, and potential damage to the membrane. Color composite (SYTO 9 and PI). -- astro-ph.EP

Astrochemistry, Astrogeology, Extremeophiles and Extreme Environments, Fossils & Paleontology, Meteorites & Asteroids, Microbiology & Virology, Panspermia, Radiation, Space Weather & Heliophysics, Status Report

Protective Effects of Halite to Vacuum and Vacuum-Ultraviolet Radiation: A Potential Scenario During a Young Sun Superflare

by Keith CowingNovember 17, 2023November 17, 2023

Halite (NaCl mineral) has exhibited the potential to preserve microorganisms for millions of years on Earth. This mineral was also identified on Mars and in meteorites.

The first public display of a sample from asteroid Bennu Credit: (NASA/Keegan Barber)

Astrochemistry, Astrogeology, Comets and Asteroids, Meteorites & Asteroids, Missions & Hardware, Press Release

National Museum of Natural History Unveils Display of Asteroid Bennu Sample

by Keith CowingNovember 3, 2023

The first public display of a sample from asteroid Bennu is seen, Friday, Nov. 3, 2023, at the Smithsonian’s National Museum of Natural History in Washington.

Schematic diagram of the idealised planetary system considered in this work with equally spaced planets (brown circles, semi-major axis ai) scattering comets (small dark blue circles) from the snow-line. The blue region represents the volatile-rich region of the disc where comets occur, and the green region represents the habitable zone. Low velocity cometary impacts onto habitable planets will follow the lower arrows, which sketch the dynamically cold scattering between adjacent planets. The dynamically hot scattering as shown by the upper arrows, will result in high velocity impacts. -- astro-ph.EP

Astrochemistry, Astrogeology, Biochemistry & Organic Chemistry, Comets and Asteroids, Exoplanets, -moons, -comets, Meteorites & Asteroids, Panspermia, Status Report

Can Comets Deliver Prebiotic Molecules To Rocky Exoplanets?

by Keith CowingOctober 23, 2023October 20, 2023

In this work we consider the potential of cometary impacts to deliver complex organic molecules and the prebiotic building blocks required for life to rocky exoplanets. Numerical experiments have demonstrated […]

Diagram of ε46Ti vs. ε50Ti for CB, CH and CR chondrite samples investigated in the present study. Bulk CR data for Acfer 139 (dark blue square) and NWA 801(gray square) are from this study and from Zhang et al. (2012), respectively. Literature data for different carbonaceous chondrite groups are stated as composite points averaging multiple samples within each group and are shown for comparison (white squares). The weighted ε50Ti– ε46Ti regression (solid black line) and related error envelopes were calculated using Isoplot, and include bulk meteorite data available from previous works. All reported uncertainties reflect 95% confidence intervals (95% CI). Literature data were taken from the recent compilation of Burkhardt et al. (2019) and references therein. -- astro-ph.EP

Astrochemistry, Astrogeology, Biosignatures & Paleobiology, Comets and Asteroids, Meteorites & Asteroids, Status Report

Age And Genetic Relationships Among CB, CH and CR Chondrites

by Keith CowingOctober 23, 2023October 20, 2023

The carbonaceous Bencubbin-like (CB), high-metal (CH), and Renazzo-like (CR) chondrites are metal-rich chondrites that have been suggested to be genetically linked and are sometimes grouped together as the CR chondrite […]

The positions of the fragments in the (𝑎 − 𝑒) plane that collided with the Sun or one of the rocky planets for different impact velocities and angles (see Table 2). The upper panels depict simulations with 𝜃 = 30◦ while the lower panels for 𝜃 = 45◦ . The colors indicate the fragments colliding with the different celestial bodies, while the initial position of all bodies involved in the 𝑁-body simulation is indicated in grey in the background. -- astro-ph.EP

Astrochemistry, Astrogeology, Atmospheres, Climate, Weather, Biogeochemical Cycles & Geobiology, Comets and Asteroids, Gaia - Planetary Perspectives, Habitable Zones, Icy Worlds, Meteorites & Asteroids, Origin & Evolution of Life, Status Report, Water/Hycean Worlds & Oceanography

The Evolution Of Collision Debris Near The ν6 Secular Resonance And Its Role In The Origin Of Terrestrial Water

by Keith CowingOctober 19, 2023October 19, 2023

This work presents novel findings that broadens our understanding of the amount of water that can be transported to Earth. The key innovation lies in the combined usage of Smoothed […]

Simulated nicotinic acid abundances compared to measured values in carbonaceous chondrites and asteroid (162173) Ryugu. A rock density of 3 g cm−3 , a porosity of 0.2, [56–58] and an ice density of 0.917 g cm−3 completely filling the pores (after all radionuclides have decayed and aqueous activity has ceased) were assumed as the properties of the planetesimal/carbonaceous chondrite hosting the chemical synthesis. The simulations were run at a pressure of 100 bar. From left to right, the plotted bars show the simulated molecular abundance of nicotinic acid (solid black line on the very left) for the whole temperature range of liquid water, as well as the abundances measured in samples of Cb asteroid (162173) Ryugu collected during the Hayabusa2 spacecraft mission, [14] in the CI chondrite Orgeil, [14] several Antarctic CM2 chondrites, [12] the CM2 chondrites Murchison and Murray, and the ungrouped C2 chondrite Tagish Lake [13] as lines and shaded ranges described in the legend. Each time, the measured nicotinic acid abundance and the sum of all isomers (nicotinic acid, isonicotinic acid, picolinic acid) are given, since thermochemical equilibrium simulations cannot distinguish between isomers. The type of extraction method used (hot water, cold water ultrasonication, HCl-hydrolyzed, formic acid) is denoted next to each panel. A tabulated version of the data presented here is available in the Supporting Information in Table S1. -- astro-ph.EP

Astrochemistry, Biochemistry & Organic Chemistry, Comets and Asteroids, Genomics, Proteomics, Bioinformatics, Imaging & Spectroscopy, Meteorites & Asteroids, Origin & Evolution of Life, Status Report

Prebiotic Vitamin B3 Synthesis In Carbonaceous Planetesimals

by Keith CowingOctober 19, 2023October 19, 2023

Aqueous chemistry within carbonaceous planetesimals is promising for synthesizing prebiotic organic matter essential to all life.

Meteorites & Asteroids

Renaissance For Magnetotactic Bacteria In Astrobiology

Prebiotic Syntheses of Organophosphorus Compounds from Reduced Source of Phosphorus in Non-Aqueous Solvents

Methodologies for 176Lu-176Hf Analysis of Zircon Grains from the Moon and Beyond

Cliff Collapse On Comet 67P/Churyumov-Gerasimenko – I. Aswan

Protective Effects of Halite to Vacuum and Vacuum-Ultraviolet Radiation: A Potential Scenario During a Young Sun Superflare

National Museum of Natural History Unveils Display of Asteroid Bennu Sample

Can Comets Deliver Prebiotic Molecules To Rocky Exoplanets?

Age And Genetic Relationships Among CB, CH and CR Chondrites

The Evolution Of Collision Debris Near The ν6 Secular Resonance And Its Role In The Origin Of Terrestrial Water

Prebiotic Vitamin B3 Synthesis In Carbonaceous Planetesimals

Ancient Layers On Mars Exposed By A Crater Within A Crater In Terra Sirenum

Send Your Name to Titan Aboard NASA’s Dragonfly Astrobiology Mission

Reconciling Giant Impacts with the Radius Valley: The Role of Silicate-Hydrogen Miscibility for Sub-Neptunes

Comprehensive Visible and Near-infrared Keck and Gemini Monitoring and Characterization of Interstellar Comet 3I/ATLAS during its Encounter with the Solar System

ExoVetter and a TESS Exoplanet Transit Search of Kepler Stars as Ground Truth