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"Craters"
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YOLO-Crater Model for Small Crater Detection
Craters are the most prominent geomorphological features on the surface of celestial bodies, which plays a crucial role in studying the formation and evolution of celestial bodies as well as in landing and planning for surface exploration. Currently, the main automatic crater detection models and datasets focus on the detection of large and medium craters. In this paper, we created 23 small lunar crater datasets for model training based on the Chang’E-2 (CE-2) DOM, DEM, Slope, and integrated data with 7 kinds of visualization stretching methods. Then, we proposed the YOLO-Crater model for Lunar and Martian small crater detection by replacing EioU and VariFocal loss to solve the crater sample imbalance problem and introducing a CBAM attention mechanism to mitigate interference from the complex extraterrestrial environment. The results show that the accuracy (P = 87.86%, R = 66.04%, and F1 = 75.41%) of the Lunar YOLO-Crater model based on the DOM-MMS (Maximum-Minimum Stretching) dataset is the highest and better than that of the YOLOX model. The Martian YOLO-Crater, trained by the Martian dataset from the 2022 GeoAI Martian Challenge, achieves good performance with P = 88.37%, R = 69.25%, and F1 = 77.65%. It indicates that the YOLO-Crater model has strong transferability and generalization capability, which can be applied to detect small craters on the Moon and other celestial bodies.
Journal Article
Hanna Mattes : searching for the cold spot
Searching for the Cold Spot' carries us off into a magical world. In analog photographs Hanna Mattes captures meteorite craters, stones of cosmic origin, as well as breathtakingly filigreed minerals. She traveled through large parts of the USA on her search for craters that were created by the impact of meteorites.00While dealing with such occurrences and places steeped in legend, Hanna Mattes finds her very own visual interpretation that is neither purely documentary nor excessively esoteric. Her photographs?occasionally transformed through the use of watercolors? capture the mysteries and stunning relics without robbing them of their secrets or their fascination. At the same time Matthes combed through mineralogical collections in diverse natural history museums, looking for unusual relics from interplanetary space, ores, opals and crystalline quartzes. Hanna Mattes? first photographic monograph inspires us to an almost metaphysical contemplation about the life-giving, but also life-destroying powers of meteorites.
Book
Progresses and prospects of impact crater studies
Crater is a geologic structure in solid bodies (including the terrestrial planets, moons, and asteroids) formed by hyper-speed impact, and the impact process is extremely important to the formation and evolution of these celestial bodies. This paper presents a review of the studies on remote sensing observation, formation mechanism, and scientific application of craters. On the remote sensing study of craters, the topographic characteristics of the micro-craters, simple craters, complex craters, and impact basins are described; the related parameters in the morphological studies of craters are subsequently introduced, and the distribution characteristics of the minerals and rock types during the impact excavation process are analyzed; the methods of crater identification and the crater databases on the Moon, Mars, Ceres, and Vesta are summarized. On the studies of crater formation mechanism, the general formation process of the craters is firstly described, and then the most frequently used methods are presented, and the importance of the empirical equations is also elucidated. On the scientific applications of the craters, the principle and currently utilization of the planetary surface dating method with crater size-frequency distribution are firstly presented, and the applications, including modeling the lunar regolith formation and thickness derivation of both the regolith and basalt, are reviewed. Finally, the future prospects of the formation mechanism study of the craters are discussed.
Journal Article
The women of the moon : tales of science, love, sorrow, and courage
\"Accounts of the lives and achievements of the 28 women [scientists] who each have a crater on the moon named in their honour\"--Publisher's website.
Book
Detection of Water in the LCROSS Ejecta Plume
Several remote observations have indicated that water ice may be presented in permanently shadowed craters of the Moon. The Lunar Crater Observation and Sensing Satellite (LCROSS) mission was designed to provide direct evidence (1). On 9 October 2009, a spent Centaur rocket struck the persistently shadowed region within the lunar south pole crater Cabeus, ejecting debris, dust, and vapor. This material was observed by a second \"shepherding\" spacecraft, which carried nine instruments, including cameras, spectrometers, and a radiometer. Near-infrared absorbance attributed to water vapor and ice and ultraviolet emissions attributable to hydroxyl radicals support the presence of water in the debris. The maximum total water vapor and water ice within the instrument field of view was 155 ± 12 kilograms. Given the estimated total excavated mass of regolith that reached sunlight, and hence was observable, the concentration of water ice in the regolith at the LCROSS impact site is estimated to be 5.6 ± 2.9% by mass. In addition to water, spectral bands of a number of other volatile compounds were observed, including light hydrocarbons, sulfur-bearing species, and carbon dioxide.
Journal Article
Target Earth : meteorites, asteroids, comets, and other cosmic intruders that may threaten our planet
\"An asteroid impact led to the extinction of the dinosaurs. Will another cosmic missile soon be heading our way? Govert Schilling offers a guide to the projectiles that have targeted our planet\"-- Provided by publisher.
BOOK
Chronology, Local Stratigraphy, and Foreign Ejecta Materials at the Chang'e‐6 Landing Site: Constraints on the Provenance of Samples Returned From the Moon's Farside
China's Chang'e‐6 (CE‐6) mission has returned the first‐ever lunar farside samples from a mare plain on the southern Apollo basin floor. The crater statistics of the CE‐6 mare unit and the provenance of the samples are crucial in interpreting the CE‐6 sample analysis results and re‐calibrating the crater chronology function. Here, we conduct a thorough survey of the formation sequence and main source craters of ejecta materials at the sampling area. Our results show that the sampling mare unit has a model age of ∼2.8 Ga and the CE‐6 scooped and drilled samples mainly come from the proximal ejecta of nearby small craters and the local regolith. The total abundance of foreign (non‐mare) materials, primarily from Chaffee S and Vavilov craters, is ∼9.3%. The Chaffee S ejecta may contain lunar upper mantle materials previously excavated by the South Pole‐Aitken impact, which will shed light on the materials of the Moon's interior. Plain Language Summary In June 2024, China's Chang'e‐6 probe successfully returned the first‐ever lunar farside samples of 1,935.3 g, from the Apollo basin within the South Pole Aitken (SPA) basin, the largest, deepest, and oldest impact basin on the Moon. The age and sources of the samples are vital in understanding the geological history of the landing region and the whole Moon. In this study, we obtain the model ages of the Chang'e‐6 mare unit by impact crater statistics and conduct a thorough survey of the foreign ejecta materials from nearby and distal crater ejecta. We find that the Chang'e‐6 scooped and drilled samples are mainly from the proximal ejecta of nearby small craters and the local regolith, both having a dominant composition of intermediate‐Ti mare basalts. The surface age of the Chang'e‐6 mare unit is ∼2.8 billion years from crater density measurements, which can facilitate the refinement of lunar chronology function. Foreign (non‐mare) materials likely account for a minor fraction (∼9.3%) of the returned samples, primarily from Chaffee S and Vavilov craters. The Eratosthenian‐aged Chaffee S crater may have delivered lunar upper mantle materials previously excavated by the SPA impact, which could potentially be recognized in the Chang'e‐6 samples. Key Points The Chang'e‐6 scooped samples are predominantly from local ejecta, and the drilled samples mostly originate from local ejecta and regolith Both samples are mainly composed of local basalts, with a model age of ∼2.8 Ga, and foreign materials make up a minor fraction (∼9.3%) Chaffee S crater delivered the most foreign materials, which may contain deep‐seated materials and be collected by the Chang'e‐6 mission
Journal Article
Fire in the sky : cosmic collisions, killer astroids, and the race to defend Earth
A \"historical survey about asteroid hits sustained by Earth and the defenses being prepared against future asteroid-caused catastrophe\"-- Provided by publisher.
Book
Spectroscopic Characterization of Mineralogy and Its Diversity Across Vesta
The mineralogy of Vesta, based on data obtained by the Dawn spacecraft's visible and infrared spectrometer, is consistent with howardite-eucrite-diogenite meteorites. There are considerable regional and local variations across the asteroid: Spectrally distinct regions include the south-polar Rheasilvia basin, which displays a higher diogenitic component, and equatorial regions, which show a higher eucritic component. The lithologic distribution indicates a deeper diogenitic crust, exposed after excavation by the impact that formed Rheasilvia, and an upper eucritic crust. Evidence for mineralogical stratigraphic layering is observed on crater walls and in ejecta. This is broadly consistent with magma-ocean models, but spectral variability highlights local variations, which suggests that the crust can be a complex assemblage of eucritic basalts and pyroxene cumulates. Overall, Vesta mineralogy indicates a complex magmatic evolution that led to a differentiated crust and mantle.
Journal Article