Explore the vast range of titles available.

The Diviner Lunar Radiometer Experiment onboard the Lunar Reconnaissance Orbiter has measured solar reflectance and mid‐infrared radiance globally, over four diurnal cycles, at unprecedented spatial and temporal resolution. These data are used to infer the radiative and bulk thermophysical properties of the near‐surface regolith layer at all longitudes around the equator. Normal albedos are estimated from solar reflectance measurements. Normal spectral emissivities relative to the 8‐μm Christiansen Feature are computed from brightness temperatures and used along with albedos as inputs to a numerical thermal model. Model fits to daytime temperatures require that the albedo increase with solar incidence angle. Measured nighttime cooling is remarkably similar across longitude and major geologic units, consistent with the scarcity of rock exposures and with the widespread presence of a near‐surface layer whose physical structure and thermal response are determined by pulverization through micrometeoroid impacts. Nighttime temperatures are best fit using a graded regolith model, with a ∼40% increase in bulk density and an eightfold increase in thermal conductivity (adjusted for temperature) occurring within several centimeters of the surface. Key Points LRO Diviner reveals radiative and thermophysical properties of the lunar surface Lunar daytime temperatures require albedo dependence on solar incidence angle Lunar nighttime temperatures require graded structure in upper cm of regolith

Surface temperatures derived from thermal infrared measurements provide a means of understanding the physical properties of the lunar surface. The contrasting thermophysical properties between rocks and regolith fines cause multiple temperatures to be present within the field of view of nighttime multispectral data returned from the Lunar Reconnaissance Orbiter (LRO) Diviner Radiometer between 60°N/S latitudes. Regolith temperatures are influenced by the presence of rocks in addition to factors such as the thermophysical properties of the regolith fines, latitude and local slopes, and radiative heating from adjacent crater walls. Preliminary comparisons of derived rock concentrations with LRO Camera images show both qualitative and quantitative agreement. Although comparisons of derived rock concentrations with circular polarization ratio radar data sets display general similarities, there are clear differences between the two data sets in the relative magnitude and areal extent of rocky signatures. Several surface units can be distinguished based on their regolith temperature and rock concentration values and distributions including maria and highlands surfaces, rocky impact craters, rilles, and wrinkle ridges, dark mantled deposits, and isolated cold surfaces. Rock concentrations are correlated with crater age and rocks are only preserved on the youngest surfaces or where steep slopes occur and mass wasting prevents mantling with fines. The presence of rocky surfaces excavated by young impacts allows for the estimation of minimum regolith thickness from the size of the impact. The derived rock concentrations confirm the presence of thicker regolith cover in the highlands and in locations of radar‐dark haloes. Key Points Global rock concentration and regolith fines temperature maps have been produced Most lunar surfaces except steep slopes have low rock concentrations Global thermophysical units have been identified

Lunar cold spots are extensive, ray‐like regions of reduced nighttime temperature surrounding young impact craters. Using improved Diviner temperature maps, we identify a faint cold spot surrounding South Ray crater at the Apollo 16 landing site. South Ray crater's age (∼${\\sim} $ 2.08 ± 0.17 Ma) is consistent with the fading trend of other large cold spots, making it the oldest known cold spot. Astronaut footprint depths collected during the Apollo missions indicate a statistically lower relative density within the upper ∼${\\sim} $ 15 cm of regolith at Apollo 16 compared to other Apollo sites. This agrees with thermal modeling, which requires a lower average density to explain the reduced nighttime temperatures. These results provide both in situ and orbital evidence that cold spots result from a decompaction of the upper centimeters of regolith. Further analysis of Apollo 16 samples and observations can inform our understanding of cold spot formation, and their influence on regolith evolution globally.

The Diviner Lunar Radiometer Experiment on NASA’s Lunar Reconnaissance Orbiter will be the first instrument to systematically map the global thermal state of the Moon and its diurnal and seasonal variability. Diviner will measure reflected solar and emitted infrared radiation in nine spectral channels with wavelengths ranging from 0.3 to 400 microns. The resulting measurements will enable characterization of the lunar thermal environment, mapping surface properties such as thermal inertia, rock abundance and silicate mineralogy, and determination of the locations and temperatures of volatile cold traps in the lunar polar regions.

We present new laboratory thermal infrared emissivity spectra of the major silicate minerals identified on the Moon measured under lunar environmental conditions and evaluate their application to lunar remote sensing data sets. Thermal infrared spectral changes between ambient and lunar environmental conditions are characterized for the first time over the 400∼1700 cm−1 (6–25 μm) spectral range for a fine‐particulate mineral suite including plagioclase (albite and anorthite), pyroxene (enstatite and augite), and olivine (forsterite). The lunar environment introduces observable effects in thermal infrared emissivity spectra of fine particulate minerals, which include: (1) a shift in the Christiansen feature (CF) position to higher wave numbers (shorter wavelengths), (2) an increase in the overall spectral contrast, and (3) decreases in the spectral contrast of the reststrahlen bands and transparency features. Our new measurements demonstrate the high sensitivity of thermal infrared emissivity spectra to environmental conditions under which they are measured and provide important constraints for interpreting new thermal infrared data sets of the Moon, including the Diviner Lunar Radiometer Experiment onboard NASA's Lunar Reconnaissance Orbiter. Full resolution laboratory mineral spectra convolved to Diviner's three spectral channels show that spectral shape, CF position and band ratios can be used to distinguish between individual mineral groups and lunar lithologies. The integration of the thermal infrared CF position with near infrared spectral parameters allows for robust mineralogical identifications and provides a framework for future integrations of data sets across two different wavelength regimes. Key Points New thermal infrared emission spectra of silicates under lunar conditions Characterize spectral differences between ambient and lunar conditions spectra Resample lab spectra to Diviner resolution to apply to new remotely sensed data

This essay was first presented at the 2010 Ludwig Holberg Prize Symposium in Bergen, Norway, where I, as the prize recipient, was asked to describe my work and its import for our period of globalization. The essay first traces the interconnected processes of \"decentering\" history in Western historiography in the half century after World War II: the move to working people and \"subaltern classes\"; to women and gender; to communities defined by ethnicity and race; to the study of non-Western histories and world or global history, in which the European trajectory is only one of several models. Can the historian hold onto the subjects of \"decentered\" social and cultural history, often local and full of concrete detail, and still address the perspectives of global history? To suggest an answer to this question, I describe my own decentering path from work on sixteenth-century artisans in the 1950s to recent research on non-European figures such as the Muslim \"Leo Africanus\" (Hasan al-Wazzan). I then offer two examples in which concrete cases can serve a global perspective. One is a comparison of the literary careers of Ibn Khaldun and Christine de Pizan in the scribal cultures on either side of the Mediterranean in the late fourteenth and early fifteenth centuries. The other is the transmission and transformation of practices of divination, healing, and detection from Africa to the slave communities of Suriname in the seventeenth and eighteenth centuries.

Lunar meteorites provide access to a geographically unconstrained record of the Moon, offering key insights into crustal diversity and interior evolution beyond the Apollo and Luna landing sites. Among them, the feldspathic breccia NWA 11421 is of particular interest because of its complex mineralogy and the presence of a dunite clast interpreted as a fragment of the lunar mantle. We present a non-destructive, multi-scale characterization of NWA 11421 using VIS–IR spectroscopy, µ-FTIR mapping, and µ-EDXRF. Results identify a polymict feldspathic breccia dominated by an anorthite matrix, with significant low-Ca pyroxene and olivine occurring as discrete mafic microdomains at the micro-scale. Near-infrared pyroxene band positions and Christiansen Feature (CF) value further indicate relatively mafic and primitive components. In addition, NWA 11421 CF value match with lunar crater-ejecta regions observed by the Diviner radiometer (LRO). These findings are consistent with a deep crustal or shallow mantle origin for NWA 11421 and may provide useful constraints for the selection of future landing sites, particularly in the context of ISRU-oriented human exploration, where mafic components are key sources of Fe and Mg.

The chemical distribution on the lunar surface results from the combined effects of both endogenic and exogenic geological processes. Exploring global maps of chemical composition helps to gain insights into the compositional variation among three major geological units, unraveling the geological evolution of the Moon. The existing oxide abundance maps were obtained from spectral images of remote sensing and geochemical data from samples returned by Apollo and Luna, missing the chemical characteristics of the Moon’s late critical period. In this study, by adding geochemical data from Chang’e (CE)-5 lunar samples, we construct inversion models between the Christiansen feature (CF) and oxide abundance of lunar samples using the particle swarm optimization–extreme gradient boosting (PSO-XGBoost) algorithm. Then, new global oxide maps (Al2O3, CaO, FeO, and MgO) and Mg# with the resolution of 32 pixels/degree (ppd) were produced, which reduced the space weathering effect to some extent. The PSO-XGBoost models were compared with partial least square regression (PLSR) models and four previous results, indicating that PSO-XGBoost models possess the capability to effectively describe nonlinear relationships between CF and oxide abundance. Furthermore, the average contents of our results and the Diviner results for 21 major maria demonstrate high correlations, with R2 of 0.95, 0.82, 0.95, and 0.86, respectively. In addition, a new Mg# map was generated, which reveals different magmatic evolutionary processes in the three geologic units.

High-alumina (HA) mare basalts play a critical role in lunar mantle differentiation. Although remote sensing methods have speculated their potential presence regions based on sample FeO and TiO2 compositions, the location and distribution characteristics of HA basalts have not been provided. In this study, the compositions of exposed rocks in Mare Imbrium were determined using Lunar Reconnaissance Orbiter (LRO) Diviner oxides and Lunar Prospector Gamma-Ray Spectrometer (LP-GRS) Thorium (Th) products. The exposed HA basalts were identified based on laboratory lithology classification criteria and Al2O3 abundance. The HA basalt units were mapped based on lunar topographic data, and their morphological geological characteristics were calculated based on elevation data. The results show that there are 8406 HA basalt pixels and 17 original units formed by volcanic eruptions in Mare Imbrium. The statistics of their morphology characteristics show that the HA basalts are widely distributed in the northern part of Mare Imbrium, and their compositions have a large range of variation. These units have different area and volume, and the layers formed were discontinuous. The characteristic analysis shows that the aluminum-bearing volcanic activities in Mare Imbrium were irregular. The eruptions of four different source regions occurred in three phases, and the scale and extent of the eruptions were different. The results in this study provide reliable evidence for the heterogeneity of the lunar mantle and contribute valuable information to the formation process of early lunar mantle materials.

“Two negroes hanged,” John Gabriel Stedman wrote in his Suriname journal for March 9, 1776, and then two days later, among his purchases of “soap, wine, tobacco, [and] rum” and his dinners with an elderly widow, he records, “A negro's foot cut off.” Stedman expanded on these events in the later Narrative of his years as a Dutch–Scottish soldier fighting against the Suriname Maroons: And now, this being the period of the [court] sessions, another Negro's leg was cut off for sculking from a task to which he was unable, while two more were condemned to be hang'd for running away altogether. The heroic behavior of one of these men deserves particularly to be quotted, he beg'd only to be heard for a few moments, which, being granted, he proceeded thus––“I was born in Africa, where defending my prince during an engagement, I was made a captive, and sold for a slave by my own countrimen. One of your countrimen, who is now to be my judge, became then my purchaser, in whose service I was treated so cruelly by his overseer that I deserted and joined the rebels in the woods . . .”To which his former master, who as he observed was now one of his judges, made the following laconick reply, “Rascal, that is not what we want to know. But the torture this moment shall make you confess crimes as black as yourself, as well as those of your hateful accomplices.” To which the Negroe, who now swel'd in every vain with rage [replied, holding up his hands], “Massera, the verry tigers have trembled for these hands . . . and dare you think to threaten me with your wretched instrument? No, I despise the greatest tortures you can now invent, as much as I do the pitiful wrech who is going to inflict them.” Saying which, he threw himself down on the rack, where amidst the most excruciating tortures he remained with a smile and without they were able to make him utter a syllable. Nor did he ever speak again till he ended his unhappy days at the gallows.