scholarly journals Self-Secondaries Formed by Cold Spot Craters on the Moon

2021 ◽  
Vol 13 (6) ◽  
pp. 1087
Author(s):  
Yiren Chang ◽  
Zhiyong Xiao ◽  
Yang Liu ◽  
Jun Cui
Keyword(s):  
Systematic Investigation ◽  
Impact Craters ◽  
Spatial Density ◽  
Cold Spot ◽  
The Moon ◽  
Potential Threat ◽  
Frequency Distributions ◽  
Crater Size ◽  
The Impact ◽  
Density Pattern

Self-secondaries are a population of background secondaries, and they have been observed on top of impact melt and ballistically emplaced ejecta deposits on various planetary bodies. Self-secondaries are formed by impacts of sub-vertically launched ejecta, but the launch mechanism is not confirmed. The potential threat of self-secondaries to the theoretical and applicable reliability of crater chronology has been noted, but not constrained. Hitherto discovered self-secondaries were located around complex impact craters, but their potential existence around simple craters has not been discovered. Here we report the first discovery of self-secondaries around lunar cold spot craters, which are an extremely young population of simple craters formed within the past ~1 million years on the Moon. Self-secondaries are widespread on layers of cascading flow-like ejecta deposits around cold spot craters. The spatial density of self-secondaries dwarfs that of potential primary craters. The spatial distribution of self-secondaries is highly heterogeneous across the ejecta deposits. With respect to the impactor trajectory that formed cold spot craters, self-secondaries formed at the downrange of the ejecta deposits have the largest spatial density, while those at the uprange have the smallest density. This density pattern holds for all cold spot craters that were formed by non-vertical impacts, but self-secondaries do not exhibit other systematic density variations at different radial distances or at other azimuths with respect to the impactor trajectory. Among known mechanics of ejecting materials to the exterior of impact craters, impact spallation is the most likely scenario to account for the required large ejection velocities and angles to form self-secondaries. The production population of self-secondaries is estimated based on the highly diverse crater size-frequency distributions across the ejecta deposits of cold spot craters. For a better understanding of the impact history on the Moon, a systematic investigation for the effect of self-secondaries on lunar crater chronology is required.

Transitional impact craters on the Moon: Insight into the effect of target lithology on the impact cratering process

2018 ◽  
Author(s):  
Gordon R. Osinski ◽  
Elizabeth A. Silber ◽  
Jacqueline Clayton ◽  
Richard A. F. Grieve ◽  
Kayle Hansen ◽  
...  
Keyword(s):  
Impact Craters ◽  
The Moon ◽  
Impact Cratering ◽  
The Impact ◽  
Insight Into

scholarly journals Three-Dimensional Model of the Moon with Semantic Information of Craters Based on Chang’e Data

Sensors ◽  
2021 ◽  
Vol 21 (3) ◽  
pp. 959
Author(s):  
Yunfan Lu ◽  
Yifan Hu ◽  
Jun Xiao ◽  
Lupeng Liu ◽  
Long Zhang ◽  
...  
Keyword(s):  
Reference Frame ◽  
3D Model ◽  
Semantic Information ◽  
Three Dimensional ◽  
Impact Craters ◽  
Detection Methods ◽  
The Moon ◽  
Three Dimensional Model ◽  
Data Set ◽  
The Impact

China’s Chang’e lunar exploration project obtains digital orthophoto image (DOM) and digital elevation model (DEM) data covering the whole Moon, which are critical to lunar research. The DOM data have three resolutions (i.e., 7, 20 and 50 m), while the DEM has two resolutions (i.e., 20 and 50 m). Analysis and research on these image data effectively help humans to understand the Moon. In addition, impact craters are considered the most basic feature of the Moon’s surface. Statistics regarding the size and distribution of impact craters are essential for lunar geology. In existing works, however, the lunar surface has been reconstructed less accurately, and there is insufficient semantic information regarding the craters. In order to build a three-dimensional (3D) model of the Moon with crater information using Chang‘e data in the Chang‘e reference frame, we propose a four-step framework. First, software is implemented to annotate the lunar impact craters from Chang’e data by complying with our existing study on an auxiliary annotation method and open-source software LabelMe. Second, auxiliary annotation software is adopted to annotate six segments in the Chang’e data for an overall 25,250 impact crater targets. The existing but inaccurate craters are combined with our labeled data to generate a larger dataset of craters. This data set is analyzed and compared with the common detection data. Third, deep learning detection methods are employed to detect impact craters. To address the problem attributed to the resolution of Chang’e data being too high, a quadtree decomposition is conducted. Lastly, a geographic information system is used to map the DEM data to 3D space and annotate the semantic information of the impact craters. In brief, a 3D model of the Moon with crater information is implemented based on Chang’e data in the Chang‘e reference frame, which is of high significance.

scholarly journals Location, orbit, and energy of a meteoroid impacting the Moon during the lunar eclipse of 2019 January 21

2019 ◽  
Vol 492 (1) ◽  
pp. 1432-1449
Author(s):  
J I Zuluaga ◽  
M Tangmatitham ◽  
P Cuartas-Restrepo ◽  
J Ospina ◽  
F Pichardo ◽  
...  
Keyword(s):  
Posterior Probability ◽  
Light Flash ◽  
Probability Distributions ◽  
Lunar Eclipse ◽  
The Moon ◽  
Impact Location ◽  
Crater Size ◽  
Rgb Images ◽  
The Impact ◽  
Geographical Locations

ABSTRACT During lunar eclipse of 2019 January 21, a meteoroid impacted the Moon producing a visible light flash. The impact was witnessed by casual observers offering an opportunity to study the phenomenon from multiple geographical locations. We use images and videos collected by observers in seven countries to estimate the location, impact parameters (speed and incoming direction), and energy of the meteoroid. Using parallax, we achieve determining the impact location at lat.$-29.43^{+0.30}_{-0.21}$, lon.$-67.89^{+0.07}_{-0.09}$, and geocentric distance as 356 553 km. After devising and applying a photometric procedure for measuring flash standard magnitudes in multiple RGB images having different exposure times, we found that the flash, had an average G-magnitude 〈G〉 = 6.7 ± 0.3. We use gravitational ray tracing (GRT) to estimate the orbital properties and likely radiant of the impactor. We find that the meteoroid impacted the moon with a speed of $14^{+7}_{-6}$ km s−1 (70 per cent C.L.) and at a shallow angle, θ < 38.2 deg. Assuming a normal error for our estimated flash brightness, educated priors for the luminous efficiency and object density, and using the GRT-computed probability distributions of impact speed and incoming directions, we calculate posterior probability distributions for the kinetic energy (median Kmed = 0.8 kton), body mass (Mmed = 27 kg) and diameter (dmed = 29 cm), and crater size (Dmed = 9 m). If our assumptions are correct, the crater left by the impact could be detectable by prospecting lunar probes. These results arose from a timely collaboration between professional and amateur astronomers that highlight the potential importance of citizen science in astronomy.

2. The Moon

2015 ◽  
pp. 17-45
Author(s):  
David A. Rothery
Keyword(s):  
Solar System ◽  
Impact Craters ◽  
Lunar Exploration ◽  
The Moon ◽  
Virtual Absence ◽  
Rock Samples ◽  
The Face ◽  
The Impact

The Earth’s Moon is the fifth largest moon in our Solar System and is made almost entirely of rock. The virtual absence of an atmosphere leads to a very large day–night range of temperature at the Moon’s surface of about 270°C. ‘The Moon’ outlines the phases, orbit, and rotation of the Moon and goes on to describe the face of the Moon seen from Earth and the farside of the Moon first observed in 1959 from the Soviet probe Luna 3. The impact craters observed on the Moon are explained, and the results of lunar exploration and dating of rock samples brought back are described, but what are the Moon’s origins?

Fluctuation of recent large impact craters rate on Mars from automatic crater detection

2020 ◽  
Author(s):  
Anthony Lagain ◽  
Misha Kreslavsky ◽  
Gretchen Benedix ◽  
David Baratoux ◽  
Phil Bland ◽  
...  
Keyword(s):  
Impact Crater ◽  
Impact Craters ◽  
Asteroid Belt ◽  
Large Impact ◽  
The Moon ◽  
Crater Detection ◽  
Impact Flux ◽  
Ejecta Blanket ◽  
The Impact ◽  
Latitudinal Band

<p>Knowledge of collision rates through time and space is essential because meteoritic impact crater counting is the only way to determine the ages of surface geological units and processes on the solid bodies of our Solar System. All chronology models assume a constant size distribution of impactors and an exponential decay of the impact flux between 4 Ga and 2.5 Ga before the present followed by a constant rate over the last 2.5 Ga. These two assumptions are challenged by recent evidence for an increase of the impact flux on the Moon and the Earth and probably on Mars associated with a decoupling between the flux of small and large impactors over the last billion years. Here, using the results of an automatic crater detection algorithm, we investigate the evolution of the rate of formation of large impact craters (Dc ≥ 20km) on Mars and thus infer the evolution of the flux of large impactors (Di > 5km) from the size-frequency distribution of small craters superposed to the ejecta blankets of large ones.</p><p>The dating of large impact craters on Mars is limited by several factors such as the degradation of ejecta blankets and the retention rate of small craters superposed to their ejecta. We therefore focused on craters ≥20km in diameter exhibiting an ejecta blanket according to the crater database and located on a latitudinal band between ±35°. We then selected those whom their ejecta are not affected by volcanic/tectonic processes or by the formation of another large nearby impact crater. The final set includes 590 impact craters.</p><p>If one can argue the impact flux cannot be fully recorded for the last 4Ga due to resurfacing processes erasing progressively the ejecta blanket and large craters themselves, Hesperian and Noachian terrains within the 35° latitudinal band should nevertheless have retained all D≥20km craters over a portion of the Amazonian period. The CSFD of craters younger than 600Ma (113 craters) superposed to these terrains is consistent with the 600Ma isochron, supporting the fact that the entire population of craters ≥20km formed over the last 600 million years on this portion of the Martian surface has been counted completely. We therefore focused on the analysis of the impact rate evolution over this range of time from this crater sub-sample.</p><p>The formation of large impact craters is not homogeneously distributed over the time range investigated here. Our data suggest an inconsistency between the flux used to date each crater and the rate inferred from these datings, thus implying that the small and large body impact fluxes are decoupled from one another. We note also sharp peaks centered around 480, 280 and 100Ma. Preliminary statistical test show that 280Ma peak is marginally significant whereas the two others are too small to be statistically significant. This pattern would be consistent with other independent arguments for increased rate with similar intensity and timing on the Moon and Mars for which the causes are probably collisions and potentially formation of asteroid families within the main asteroid belt.</p>

LUMIO: a CubeSat to monitor the lunar farside

2021 ◽  
Author(s):  
Gianmario Merisio ◽  
Vittorio Franzese ◽  
Carmine Giordano ◽  
Mauro Massari ◽  
Pierluigi Di Lizia ◽  
...  
Keyword(s):  
Lunar Surface ◽  
Simulated Data ◽  
Visible Spectrum ◽  
Parent Body ◽  
Dust Particles ◽  
The Moon ◽  
Potential Threat ◽  
Impact Flux ◽  
The Impact ◽  
Near Future

<p>Vast amounts of meteoroids and micrometeoroids continuously enter the Earth–Moon system and consequently become a potential threat. Lunar meteoroid impacts have caused a substantial change in the lunar surface and its properties. The Moon having no atmospheric blanket to protect itself, it is subjected to impacts from meteoroids ranging from a few kilograms to 10’s of grams each day. The high impact rate on the lunar surface has important implications for future human and robotic assets that will inhabit the Moon for significant periods of time. Therefore, a greater understanding of the meteoroid population in the cislunar environment is required for future exploration of the Moon.</p> <p>Moreover, refining current meteoroid models is of paramount importance for many applications. For instance, since meteoroids may travel dispersed along the orbit of their parent body, understanding meteoroids and associated phenomena can be valuable for the study of asteroids and comets themselves. Studying meteoroid impacts can help deepening the understanding of the spatial distribution of near-Earth objects in the Solar system. The study of dust particles can be also of interest because, together with the solar wind, they determine the space weather. Finally, it is critical to be able to predict impacts by relying on accurate impact flux models. That because the impact of small asteroids with Earth, even slightly larger than meteoroids, can cause severe damage.</p> <p>In this context, the Lunar Meteoroid Impacts Observer (LUMIO) is a CubeSat mission to observe, quantify, and characterise the meteoroid impacts by detecting their flashes on the lunar far-side. This complements the knowledge gathered by Earth-based observations of the lunar nearside, thus synthesising a global information on the lunar meteoroid environment. LUMIO envisages a 12U CubeSat form-factor placed in a halo orbit at Earth-Moon L2. The mission employs the LUMIO-Cam, an optical instrument capable of detecting light flashes in the visible spectrum. LUMIO is one of the two winner of ESA’s LUCE (Lunar CubeSat for Exploration) SysNova competition, and as such it is being considered by ESA for implementation in the near future. The Phase A study has been conducted in 2020 under ESA's General Support Technology Programme (GSTP) and successfully completed at the beginning of 2021, after an independent mission assessment performed by ESA’s CDF team.</p> <p>In this work, the latest results of the Phase A study of the LUMIO lunar CubeSat will be shown. An overview of the present-day LUMIO CubeSat A design will be given, with a focus on the latest developments. An overview on how LUMIO will impact the currently existing knowledge of meteoroid models will be given supported by high-fidelity simulated data.</p>

Formation of Lunar Craters and Bright Rays as a Result of Meteorite Impacts

1962 ◽  
Vol 14 ◽  
pp. 415-418
Author(s):  
K. P. Stanyukovich ◽  
V. A. Bronshten
Keyword(s):  
Explosive Charge ◽  
The Moon ◽  
Meteorite Impacts ◽  
The Earth ◽  
Lunar Craters ◽  
The Impact

The phenomena accompanying the impact of large meteorites on the surface of the Moon or of the Earth can be examined on the basis of the theory of explosive phenomena if we assume that, instead of an exploding meteorite moving inside the rock, we have an explosive charge (equivalent in energy), situated at a certain distance under the surface.

Thematic maps in the scientific studies of the moon

2019 ◽  
Vol 943 (1) ◽  
pp. 68-75
Author(s):  
S.G. Pugacheva ◽  
E.A. Feoktistova ◽  
V.V. Shevchenko
Keyword(s):  
Natural Resources ◽  
Thermal Inertia ◽  
High Growth ◽  
Lunar Soil ◽  
Nature Management ◽  
The Moon ◽  
Surface Cooling ◽  
Laser Altimeters ◽  
Space Infrastructure ◽  
The Impact

The article presents the results of astrophysical studies of the Moon’s reflected and intrinsic radiation. We studied the intensity of the Moon’s infrared radiation and, thus, carried out a detailed research of the brightness temperature of the Moon’s visible disc, estimated the thermal inertia of the coating substance by the rate of its surface cooling, and the degree of the lunar soil fragmentation. Polarimetric, colorimetric and spectrophotometric measurements of the reflected radiation intensity were carried out at different wavelengths. In the article, we present maps prepared based on our measurement results. We conducted theresearch of the unique South Pole – Aitken basin (SPA). The altitude profiles of the Apollo-11 and Zond-8 spacecrafts and the data of laser altimeters of the Apollo-16 and Apollo-15 spacecrafts were used as the main material. Basing upon this data we prepared a hypsometric map of SPA-basing global relief structure. A surface topography map of the Moon’s Southern Hemisphere is given in the article. The topography model of the SPA topography surface shows displacement centers of the altitude topographic rims from the central rim. Basing upon the detailed study of the basin’s topography as well as its “depth-diameter” ratio we suggest that the basin originated from the impact of a giant cometary body from the Orta Cloud. In our works, we consider the Moon as a part of the Earth’s space infrastructure. High growth rates of the Earth’s population, irrational nature management will cause deterioration of scarce natural resources in the near future. In our article, we present maps of the natural resources on the Moon pointing out the most promising regions of thorium, iron, and titanium. Probably in 20 or 40 years a critical mining level of gold, diamonds, zinc, platinum and other vital rocks and metals will be missing on the Earth.

scholarly journals On the Spatial Patterns of Urban Thermal Conditions Using Indoor and Outdoor Temperatures

2021 ◽  
Vol 13 (4) ◽  
pp. 640
Author(s):  
Sadroddin Alavipanah ◽  
Dagmar Haase ◽  
Mohsen Makki ◽  
Mir Muhammad Nizamani ◽  
Salman Qureshi
Keyword(s):  
Heat Stress ◽  
Air Temperature ◽  
Temperature Data ◽  
Cold Spot ◽  
Temperature Pattern ◽  
Outdoor Temperature ◽  
Residential Units ◽  
Urban Settlements ◽  
The Impact ◽  
Indoor And Outdoor

The changing climate has introduced new and unique challenges and threats to humans and their environment. Urban dwellers in particular have suffered from increased levels of heat stress, and the situation is predicted to continue to worsen in the future. Attention toward urban climate change adaptation has increased more than ever before, but previous studies have focused on indoor and outdoor temperature patterns separately. The objective of this research is to assess the indoor and outdoor temperature patterns of different urban settlements. Remote sensing data, together with air temperature data collected with temperature data loggers, were used to analyze land surface temperature (outdoor temperature) and air temperature (indoor temperature). A hot and cold spot analysis was performed to identify the statistically significant clusters of high and low temperature data. The results showed a distinct temperature pattern across different residential units. Districts with dense urban settlements show a warmer outdoor temperature than do more sparsely developed districts. Dense urban settlements show cooler indoor temperatures during the day and night, while newly built districts show cooler outdoor temperatures during the warm season. Understanding indoor and outdoor temperature patterns simultaneously could help to better identify districts that are vulnerable to heat stress in each city. Recognizing vulnerable districts could minimize the impact of heat stress on inhabitants.

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