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Numerical simulations and analysis show that the Moon locks into resonance with a statistical preference of facing either the current near-side or far-side toward Earth. The near-side is largely covered by dense, topographically low, dark mare basalts, the pattern of which to some, resembles the image of a man’s face. Although the Moon is locked in this configuration at present, the opposite one,...
Impact melt flows exterior to Copernican-age craters are observed in high spatial resolution (0.5m/pixel) images acquired by the Lunar Reconnaissance Orbiter Camera (LROC) Narrow Angle Camera (NAC). Impact melt is mapped in detail around 15 craters ranging in diameter from 2.4 to 32.5km. This survey supports previous observations suggesting melt flows often occur at craters whose shape is influenced...
We performed ion irradiation of mineral samples with 50keV He + , aimed to investigate ion irradiation effects on diagnostic spectral features. Reflectance spectra of samples in 0.375–2.5μm are measured before and after ion irradiation. Silicates, including Luobusha olivine, plagioclase and basaltic glass, have shown reddening and darkening of reflectance spectra at the VIS–NIR range. Olivine...
The lunar sodium tail extends long distances due to radiation pressure on sodium atoms in the lunar exosphere. Our earlier observations measured the average radial velocity of sodium atoms moving down the lunar tail beyond Earth (i.e., near the anti-lunar point) to be ∼12.5km/s. Here we use the Wisconsin H-alpha Mapper to obtain the first kinematically resolved maps of the intensity and velocity distribution...
In this work we report the first employment of the 2-μm absorption band parameters to estimate FeO weight percentage (wt.%) abundances from high-resolution Near-Infrared (NIR) lunar data, as measured by the SIR-2 instrument on board Chandrayaan-1. Our method is based on the algorithm originally developed by Le Mouélic et al. (Le Mouélic, S., Langevin, Y., Erard, S., Pinet, P., Chevrel, S., Daydou,...
The small crater populations (diameter smaller than 1km) are widely used to date planetary surfaces. The reliability of small crater counts is tested by counting small craters at several young and old lunar surfaces, including Mare Nubium and craters Alphonsus, Tycho and Giordano Bruno. Based on high-resolution images from both the Lunar Reconnaissance Orbiter Camera and Kaguya Terrain Camera, small...
The South Pole-Aitken (SPA) basin is the largest and oldest definitive impact structure on the Moon. To understand how this immense basin formed, we conducted a suite of SPA-scale numerical impact simulations varying impactor size, impact velocity, and lithospheric thermal gradient. We compared our model results to observational SPA basin data to constrain a best-fit scenario for the SPA basin-forming...
The Thermal Degradation Sample (TDS) experiment was one of the many investigations performed on the lunar surface during Apollo 14. Remarkably, the results of this 40year old experiment were never fully interpreted, perhaps in part because the hardware vanished after its return. Mission records, high resolution photographs returned from the mission, and recent laboratory investigations have been used...
The formation of the Moon from the debris of a slow and grazing giant impact of a Mars-sized impactor on the proto-Earth (Cameron and Ward [1976]. Lunar Planet. Sci. Conf.; Canup and Asphaug [2001]. Nature 412, 708) is widely accepted today. We present an alternative scenario with a hit-and-run collision (Asphaug [2010]. Chem. Erde 70, 199) with a fractionally increased impact velocity and a steeper...
Saturn’s moon Rhea is thought to be a simple plasma absorber, however, energetic particle observations in its vicinity show a variety of unexpected and complex interaction features that do not conform with our current understanding about plasma absorbing interactions. Energetic electron data are especially interesting, as they contain a series of broad and narrow flux depletions on either side of...
The goal of this study is to develop an efficient and accurate model for using visible–near infrared reflectance spectra to estimate the abundance of minerals on the lunar surface. Previous studies using partial least squares (PLS) and genetic algorithm–partial least squares (GA–PLS) models for this purpose revealed several drawbacks. PLS has two limitations: (1) redundant spectral bands cannot be...
Based on literature data from lunar meteorites and orbital observations it is argued that the lunar crater Giordano Bruno (22km∅) formed more than 1Ma ago and probably ejected the lunar meteorites Yamato 82192/82193/86032 at 8.5±1.5Ma ago from the Th-poor highlands of the Moon. The efficiency and time scale to deliver 3 He-rich lunar material into Earth’s sediments is discussed to assess the...
We report observations of the lunar helium exosphere made between December 29, 2011, and January 26, 2012, with the Lyman Alpha Mapping Project (LAMP) ultraviolet spectrograph on NASA’s Lunar Reconnaissance Orbiter Mission (LRO). The observations were made of resonantly scattered He i λ584 from illuminated atmosphere against the dark lunar surface on the dawn side of the terminator. We find no or...
Spectral analysis of Mare Serenitatis has been carried out using Chandrayaan-1 Moon Mineralogy Mapper (M 3 ) data in order to map the compositional diversity of the basaltic units that exist in the basin. Mare Serenitatis is characterized by multiple basaltic flows of different ages indicating a prolonged volcanism subsequent to the basin formation event. Reflectance spectra of fresh craters...
Observations of the Moon obtained by the Moon Mineralogy Mapper (M 3 ) instrument were acquired at various local viewing geometries. To compensate for this, a visible near-infrared photometric correction for the M 3 observations of the lunar surface has been derived. Images are corrected to the standard geometry of 30° phase angle with an incidence of 30° and an emission of 0°. The...
The main objective of this study is to develop a new photometric correction that is suitable for global Chang’ E-1 (CE-1) Interference Imaging Spectrometer (IIM) data. We considered two improvements in the accuracy of the photometric correction: (1) classifying the whole Moon’s surface into four classes (very bright rays, mature highlands, low FeO basalts, and high FeO basalts) based on the FeO contents;...
The Lunar Reconnaissance Orbiter Camera (LROC) provides multi-temporal and high resolution imaging of the north and south polar regions. These images delimit illuminated areas from those in shadow, and are used to analyze the illumination environment of the polar regions over the course of a lunar year. The Wide Angle Camera (WAC) provides repeat imaging of the north and south pole at a frequency...
The unusual shape of the Moon given its present rotational and orbital state has been explained as due to a fossil figure preserving a record of remnant rotational and tidal deformation (Jeffreys, H. [1915]. Mem. R. Astron. Soc. 60, 187–217; Lambeck, K., Pullan, S. [1980]. Phys. Earth Planet. Interiors 22, 29–35; Garrick-Bethell, I., Wisdom, J., Zuber, M.T. [2006]. Science 313, 652–655). However,...
Asteroids impacting the Earth partly volatilize, partly melt (O’Keefe, J.D., Ahrens, T.J. [1977]. Proc. Lunar Sci. Conf. 8, 3357–3374). While metal rapidly segregates out of the melt and sinks into the core, the vaporized material orbits the Earth and eventually rains back onto its surface. The content of the mantle in siderophile elements and their chondritic relative abundances hence is accounted...
Many lunar basins are characterized by prominent positive gravity anomalies over the basin interiors, referred to as mass concentrations or mascons. While a significant fraction of some near-side mascon anomalies can be explained as a result of the flexural support of the mare basalts within the basins, a number of basins, including Orientale, exhibit mascons in excess of those that can be plausibly...
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