Moon Archives

Schematic view of the mass range in which a fractionally large exomoon can form by an impact. The horizontal axis represents the mantle composition and the vertical axis represents the planetary mass normalized by the Earth mass M⊕. Rocky planets smaller than 6 M⊕ and icy planets smaller than 1 M⊕ are capable of forming fractionally large moons as indicated by the orange shading. Our prediction is consistent with planet–moon systems in the solar system. -- astro-ph.EP

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

Large Planets May Not Form Fractionally Large Moons

by Keith CowingDecember 27, 2023December 27, 2023

One of the unique aspects of Earth is that it has a fractionally large Moon, which is thought to have formed from a Moon-forming disk generated by a giant impact.

Collision velocity as a function of the mass of the target in Earth masses. The lowest possible collision velocity without the presence of nebular gas is vcoll = 1 vesc, a gentle scenario that always results in a merger of the two bodies. Solar System formation simulations report velocities vcoll ≈ 1–1.6 vesc, with exceedingly few near 3 vesc (e.g., Agnor et al. 1999). For simplicity, sound speeds are shown for ∼0°C and ∼1 atm conditions, a constant density of 5 g/cm3 is assumed for the escape velocity calculation, and the impactor-to-target mass ratio is 0.7. The sizes of the planet images are not to scale. -- astro-ph.EP

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

The Role Of Giant Impacts In Planet Formation

by Keith CowingDecember 27, 2023December 27, 2023

Planets are expected to conclude their growth through a series of giant impacts: energetic, global events that significantly alter planetary composition and evolution.

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 […]

a HAADF image showing region with melt bleb with large vesicles beneath it. b EDS element map shows the bleb is silicate with variable composition of elements including Ti. c HAADF image showing individual pixels in the spectra image. d Low-loss EELS from pixels noted in (c). Solid numbered lines are from pixels within vesicles while dotted lines are from pixels directly beneath each vesicle. Solid black line is from unaltered apatite and shows average low-loss signal for the phase. Spectra from each vesicle offset vertically for clarity. e Map of relative intensity of O pre-peak at 531 eV (median filter) showing the regions with smaller pre-peak around the larger vesicles and the surface region with very sharp pre-peak. The silicate and carbon coat have no pre-peak. f Selected oxygen core-loss spectra summed from regions with similar pre-peak intensity, normalized at 540 eV. The oxygen K-edge EELS show large variation around the vesicles in this region beneath the silicate melt bleb. Dotted lines indicate window used for pre-peak map. -- NRL/Nature

Artemis & Lunar Exploration, Astrochemistry, Astrogeology, Moon, Press Release, Space Weather & Heliophysics

Hydrogen Detected In Lunar Samples

by Keith CowingNovember 24, 2023November 24, 2023

U.S. Naval Research Laboratory (NRL) researchers have discovered solar-wind hydrogen in lunar samples, which indicates that water on the surface of the Moon may provide a vital resource for future […]

Artemis & Lunar Exploration, Away Teams & Field Reports, Caves, Craters, Mountains, Subsurface, Lava Tubes, Exploration Gear & Tech, Mapping, Geodesy, Cartography, Bathymetry, Mars, Press Release, Robotics/Rovers/UAVs

Away Team Practice: Space Exploration Goes Underground

by Keith CowingNovember 22, 2023April 4, 2024

Is there life in Martian caves? It’s a good question, but it’s not the right question—yet. An international collaboration of scientists led by NAU researcher Jut Wynne has dozens of […]

Artemis & Lunar Exploration, Gravitational Biology, Life Support Systems, Microgravity, Moon, Press Release, Space Agriculture, Space Life Science

NASA Selects 11 Space Biology Research Projects to Inform Biological Research During Future Lunar Exploration Missions

by Keith CowingNovember 22, 2023November 22, 2023

NASA announces the award of eleven grants or cooperative agreements for exciting new Space Biology research that will advance NASA’s understanding of how exposure to lunar dust/regolith impact both plant […]

The Moon-forming impact. An artist‘s impression of the collision of Theia with Earth. Credit: STEP-ANI-MOTION Studio für Computertrick GmbH, Cologne, Germany.

Atmospheres, Climate, Weather, Imaging & Spectroscopy, Moon, Origin & Evolution of Life, Status Report

The Moon-Forming Impact and the Autotrophic Origin of Life

by Keith CowingNovember 8, 2023

All ecosystems start with autotrophs, cells that convert CO2 to organics. In autotrophic theories for origins, life started from CO2. The Moon-forming impact supplied pure CO2 as the primordial biogenic […]

six astronauts turned ‘cavenauts’ from five space agencies headed underground in Slovenia

Analog Studies, Artemis & Lunar Exploration, Astrogeology, Away Teams & Field Reports, Caves, Craters, Mountains, Subsurface, Lava Tubes, Exploration Gear & Tech, Mapping, Geodesy, Cartography, Bathymetry, Mars, Press Release

Into The Deep: ESA’s CAVES Campaign

by Keith CowingNovember 6, 2023November 5, 2023

There is never a dull day for participants of the CAVES campaign, ESA’s field training adventure that hones the communication, problem solving and teamwork skills an international crew will need […]

Astrochemistry, Astrogeology, Biogeochemical Cycles & Geobiology, Impact events, Moon, Status Report

Origin Of The Moon And Lunar Water

by Keith CowingOctober 27, 2023October 27, 2023

Three principal concepts regarding lunar formation have been examined: the accretion hypothesis, the mega-impact theory, and the multi-impact model.

IR-VIS–UV Raman spectra of the Xanthoria elegans sample: (A) as measured spectra in a photon energy scale, photon flux × integration time × number of averages are @ 325 nm: 3.2·1013 μm−2 s−1 × 10 s × 20; @ 532 nm: 1.5·1015 μm−2 s−1 × 0.1 s × 600; @ 785 nm: 3.4·1016 μm−2 s−1 × 5 s × 10; @ 1064 nm: 1.3·1014 μm−2 s−1 × 300 s × 1; (B) stokes spectra under different excitation wavelengths after reduction of PL and background signals, Raman signal is normalized on a maximal PL signal of each original, acquired spectrum; (C) a microscopic image of the sample. Inset (color bar) in (A) shows the approximate PL band for parietin. -- Journal of Raman spectroscopy

Analog Studies, Astrogeology, Away Teams & Field Reports, Biochemistry & Organic Chemistry, Biosignatures & Paleobiology, Exploration Gear & Tech, Imaging & Spectroscopy, Mars, Moon, Status Report, Tricorders & Sensors

Comparative Raman Spectroscopy Of Astrobiology Relevant Bio-samples And Planetary Surface Analogs Under UV–VIS–IR Excitation

by Keith CowingOctober 22, 2023October 22, 2023

We investigated the potential of a laser selection in the broad optical range, from ultraviolet through visible to infrared (excitation wavelengths of 325, 532, 785, and 1064 nm) for combined analysis […]