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Lunar Impact Crater Identification and Age Estimation with Chang’E
ARTICLE https://doi.org/10.1038/s41467-020-20215-y OPEN Lunar impact crater identification and age estimation with Chang’E data by deep and transfer learning ✉ Chen Yang 1,2 , Haishi Zhao 3, Lorenzo Bruzzone4, Jon Atli Benediktsson 5, Yanchun Liang3, Bin Liu 2, ✉ ✉ Xingguo Zeng 2, Renchu Guan 3 , Chunlai Li 2 & Ziyuan Ouyang1,2 1234567890():,; Impact craters, which can be considered the lunar equivalent of fossils, are the most dominant lunar surface features and record the history of the Solar System. We address the problem of automatic crater detection and age estimation. From initially small numbers of recognized craters and dated craters, i.e., 7895 and 1411, respectively, we progressively identify new craters and estimate their ages with Chang’E data and stratigraphic information by transfer learning using deep neural networks. This results in the identification of 109,956 new craters, which is more than a dozen times greater than the initial number of recognized craters. The formation systems of 18,996 newly detected craters larger than 8 km are esti- mated. Here, a new lunar crater database for the mid- and low-latitude regions of the Moon is derived and distributed to the planetary community together with the related data analysis. 1 College of Earth Sciences, Jilin University, 130061 Changchun, China. 2 Key Laboratory of Lunar and Deep Space Exploration, National Astronomical Observatories, Chinese Academy of Sciences, 100101 Beijing, China. 3 Key Laboratory of Symbol Computation and Knowledge Engineering of Ministry of Education, College of Computer Science and Technology, Jilin University, 130012 Changchun, China. 4 Department of Information Engineering and Computer ✉ Science, University of Trento, I-38122 Trento, Italy. -
Dynamical Evolution of the Hungaria Asteroids ⇑ Firth M
Icarus 210 (2010) 644–654 Contents lists available at ScienceDirect Icarus journal homepage: www.elsevier.com/locate/icarus Dynamical evolution of the Hungaria asteroids ⇑ Firth M. McEachern, Matija C´ uk , Sarah T. Stewart Department of Earth and Planetary Sciences, Harvard University, 20 Oxford Street, Cambridge, MA 02138, USA article info abstract Article history: The Hungarias are a stable asteroid group orbiting between Mars and the main asteroid belt, with high Received 29 June 2009 inclinations (16–30°), low eccentricities (e < 0.18), and a narrow range of semi-major axes (1.78– Revised 2 August 2010 2.06 AU). In order to explore the significance of thermally-induced Yarkovsky drift on the population, Accepted 7 August 2010 we conducted three orbital simulations of a 1000-particle grid in Hungaria a–e–i space. The three simu- Available online 14 August 2010 lations included asteroid radii of 0.2, 1.0, and 5.0 km, respectively, with run times of 200 Myr. The results show that mean motion resonances—martian ones in particular—play a significant role in the destabili- Keywords: zation of asteroids in the region. We conclude that either the initial Hungaria population was enormous, Asteroids or, more likely, Hungarias must be replenished through collisional or dynamical means. To test the latter Asteroids, Dynamics Resonances, Orbital possibility, we conducted three more simulations of the same radii, this time in nearby Mars-crossing space. We find that certain Mars crossers can be trapped in martian resonances, and by a combination of chaotic diffusion and the Yarkovsky effect, can be stabilized by them. -
Timeline of Natural History
Timeline of natural history This timeline of natural history summarizes significant geological and Life timeline Ice Ages biological events from the formation of the 0 — Primates Quater nary Flowers ←Earliest apes Earth to the arrival of modern humans. P Birds h Mammals – Plants Dinosaurs Times are listed in millions of years, or Karo o a n ← Andean Tetrapoda megaanni (Ma). -50 0 — e Arthropods Molluscs r ←Cambrian explosion o ← Cryoge nian Ediacara biota – z ←Earliest animals o ←Earliest plants i Multicellular -1000 — c Contents life ←Sexual reproduction Dating of the Geologic record – P r The earliest Solar System -1500 — o t Precambrian Supereon – e r Eukaryotes Hadean Eon o -2000 — z o Archean Eon i Huron ian – c Eoarchean Era ←Oxygen crisis Paleoarchean Era -2500 — ←Atmospheric oxygen Mesoarchean Era – Photosynthesis Neoarchean Era Pong ola Proterozoic Eon -3000 — A r Paleoproterozoic Era c – h Siderian Period e a Rhyacian Period -3500 — n ←Earliest oxygen Orosirian Period Single-celled – life Statherian Period -4000 — ←Earliest life Mesoproterozoic Era H Calymmian Period a water – d e Ectasian Period a ←Earliest water Stenian Period -4500 — n ←Earth (−4540) (million years ago) Clickable Neoproterozoic Era ( Tonian Period Cryogenian Period Ediacaran Period Phanerozoic Eon Paleozoic Era Cambrian Period Ordovician Period Silurian Period Devonian Period Carboniferous Period Permian Period Mesozoic Era Triassic Period Jurassic Period Cretaceous Period Cenozoic Era Paleogene Period Neogene Period Quaternary Period Etymology of period names References See also External links Dating of the Geologic record The Geologic record is the strata (layers) of rock in the planet's crust and the science of geology is much concerned with the age and origin of all rocks to determine the history and formation of Earth and to understand the forces that have acted upon it. -
Exploring the Bombardment History of the Moon
EXPLORING THE BOMBARDMENT HISTORY OF THE MOON Community White Paper to the Planetary Decadal Survey, 2011-2020 September 15, 2009 Primary Author: William F. Bottke Center for Lunar Origin and Evolution (CLOE) NASA Lunar Science Institute at the Southwest Research Institute 1050 Walnut St., Suite 300 Boulder, CO 80302 Tel: (303) 546-6066 [email protected] Co-Authors/Endorsers: Carlton Allen (NASA JSC) Mahesh Anand (Open U., UK) Nadine Barlow (NAU) Donald Bogard (NASA JSC) Gwen Barnes (U. Idaho) Clark Chapman (SwRI) Barbara A. Cohen (NASA MSFC) Ian A. Crawford (Birkbeck College London, UK) Andrew Daga (U. North Dakota) Luke Dones (SwRI) Dean Eppler (NASA JSC) Vera Assis Fernandes (Berkeley Geochronlogy Center and U. Manchester) Bernard H. Foing (SMART-1, ESA RSSD; Dir., Int. Lunar Expl. Work. Group) Lisa R. Gaddis (US Geological Survey) 1 Jim N. Head (Raytheon) Fredrick P. Horz (LZ Technology/ESCG) Brad Jolliff (Washington U., St Louis) Christian Koeberl (U. Vienna, Austria) Michelle Kirchoff (SwRI) David Kring (LPI) Harold F. (Hal) Levison (SwRI) Simone Marchi (U. Padova, Italy) Charles Meyer (NASA JSC) David A. Minton (U. Arizona) Stephen J. Mojzsis (U. Colorado) Clive Neal (U. Notre Dame) Laurence E. Nyquist (NASA JSC) David Nesvorny (SWRI) Anne Peslier (NASA JSC) Noah Petro (GSFC) Carle Pieters (Brown U.) Jeff Plescia (Johns Hopkins U.) Mark Robinson (Arizona State U.) Greg Schmidt (NASA Lunar Science Institute, NASA Ames) Sen. Harrison H. Schmitt (Apollo 17 Astronaut; U. Wisconsin-Madison) John Spray (U. New Brunswick, Canada) Sarah Stewart-Mukhopadhyay (Harvard U.) Timothy Swindle (U. Arizona) Lawrence Taylor (U. Tennessee-Knoxville) Ross Taylor (Australian National U., Australia) Mark Wieczorek (Institut de Physique du Globe de Paris, France) Nicolle Zellner (Albion College) Maria Zuber (MIT) 2 The Moon is unique. -
Rare Earth Elements in Planetary Crusts: Insights from Chemically Evolved Igneous Suites on Earth and the Moon
minerals Article Rare Earth Elements in Planetary Crusts: Insights from Chemically Evolved Igneous Suites on Earth and the Moon Claire L. McLeod 1,* and Barry J. Shaulis 2 1 Department of Geology and Environmental Earth Sciences, 203 Shideler Hall, Miami University, Oxford, OH 45056, USA 2 Department of Geosciences, Trace Element and Radiogenic Isotope Lab (TRaIL), University of Arkansas, Fayetteville, AR 72701, USA; [email protected] * Correspondence: [email protected]; Tel.: +1-513-529-9662 Received: 5 July 2018; Accepted: 8 October 2018; Published: 16 October 2018 Abstract: The abundance of the rare earth elements (REEs) in Earth’s crust has become the intense focus of study in recent years due to the increasing societal demand for REEs, their increasing utilization in modern-day technology, and the geopolitics associated with their global distribution. Within the context of chemically evolved igneous suites, 122 REE deposits have been identified as being associated with intrusive dike, granitic pegmatites, carbonatites, and alkaline igneous rocks, including A-type granites and undersaturated rocks. These REE resource minerals are not unlimited and with a 5–10% growth in global demand for REEs per annum, consideration of other potential REE sources and their geological and chemical associations is warranted. The Earth’s moon is a planetary object that underwent silicate-metal differentiation early during its history. Following ~99% solidification of a primordial lunar magma ocean, residual liquids were enriched in potassium, REE, and phosphorus (KREEP). While this reservoir has not been directly sampled, its chemical signature has been identified in several lunar lithologies and the Procellarum KREEP Terrane (PKT) on the lunar nearside has an estimated volume of KREEP-rich lithologies at depth of 2.2 × 108 km3. -
The Hungaria Asteroids: Close Encounters and Impacts with Terrestrial Planets
Mem. S.A.It. Suppl. Vol. 26, 38 Memorie della c SAIt 2014 Supplementi The Hungaria Asteroids: close encounters and impacts with terrestrial planets M. A. Galiazzo, A. Bazso, and R. Dvorak Institute of Astronomy, University of Vienna, Turkenschanzstr.¨ 17, A-1180 Wien, Austria e-mail: [email protected] Abstract. The Hungaria asteroid family (Named after (434) Hungaria), which consists of more than 5000 members with semi-major axes between 1.78 and 2.03 AU and have in- clinations of the order of 20◦, is regarded as one source for Near-Earth Asteroids (NEAs). They are mainly perturbed by Jupiter and Mars, and are ejected because of mean motion and secular resonances with these planets and then become Mars-crossers; later they may even cross the orbits of Earth and Venus. We are interested to analyze the close encounters and possible impacts with these planets. For 200 selected objects which are on the edge of the group we integrated their orbits over 100 million years in a simplified model of the planetary system (Mars to Saturn) subject to only gravitational forces. We picked out a sam- ple of 11 objects (each with 50 clones) with large variations in semi-major axis and some of them achieve high inclinations and eccentricities in connection with mean motion and secular resonances which then leads to relatively high velocity impacts on Venus, Earth and Mars. We report all close encounters and impacts with the terrestrial planets and statistically determine the mean life and the orbital distribution of the NEAs of these Hungarias. -
Annual Report 2017
Koninklijke Sterrenwacht van België Observatoire royal de Belgique Royal Observatory of Belgium Jaarverslag 2017 Rapport Annuel 2017 Annual Report 2017 Cover illustration: Above: One billion star map of our galaxy created with the optical telescope of the satellite Gaia (Credit: ESA/Gaia/DPAC). Below: Three armillary spheres designed by Jérôme de Lalande in 1775. Left: the spherical sphere; in the centre: the geocentric model of our solar system (with the Earth in the centre); right: the heliocentric model of our solar system (with the Sun in the centre). Royal Observatory of Belgium - Annual Report 2017 2 De activiteiten beschreven in dit verslag werden ondersteund door Les activités décrites dans ce rapport ont été soutenues par The activities described in this report were supported by De POD Wetenschapsbeleid De Nationale Loterij Le SPP Politique Scientifique La Loterie Nationale The Belgian Science Policy The National Lottery Het Europees Ruimtevaartagentschap De Europese Gemeenschap L’Agence Spatiale Européenne La Communauté Européenne The European Space Agency The European Community Het Fonds voor Wetenschappelijk Onderzoek – Le Fonds de la Recherche Scientifique Vlaanderen Royal Observatory of Belgium - Annual Report 2017 3 Table of contents Preface .................................................................................................................................................... 6 Reference Systems and Planetology ...................................................................................................... -
WHAT IS the VREDEFORT DOME TEACHING US ABOUT the SEARCH for OTHER ERODED LARGE IMPACT STRUCTURES? Roger L
Bridging the Gap III (2015) 1045.pdf WHAT IS THE VREDEFORT DOME TEACHING US ABOUT THE SEARCH FOR OTHER ERODED LARGE IMPACT STRUCTURES? Roger L. Gibson, School of Geosciences, University of the Witwatersrand, PO WITS, Johannesburg 2050, South Africa; [email protected]. Introduction: Vredefort has long been held to be extent of these breccias cannot be used as an indicator the oldest, largest and most deeply exhumed impact of the original limits of the impact structure. structure on Earth; however, in recent years its pre- With at least half the vertical extent of continental eminence in all three aspects has been challenged. crust typically being crystalline, a major problem may Evaluating the scientific debate around the claims of arise with trying to identify central uplifts on lithologi- the challengers [1,2,3] to these titles invokes a sense of cal or geophysical grounds; and traces of the wider déjà vu when one considers the decades-long history of crater dimensions are even less likely to be defined. debate about whether Vredefort itself originated by Age: The 2020 ± 5 Ma age of the Vredefort impact impact. This presentation briefly reviews the debate is based on U-Pb single-zircon geochronology of a around the impact-related features in the Vredefort variety of melt types. Dating of igneous zircons from Dome, with the main focus being the extent and inten- the impact-melt rock has been complemented by others sity of impact-induced thermal effects that play a sig- from voluminous pseudotachylitic breccias from the nificant role in masking potential diagnostic features. -
Location #1: Peary/Whipple Crater
Location, Location, Location A Lunar Investment Strategy Hoyt Davidson Near Earth LLC June 2017 ISU's International Institute of Space Commerce Lunar Economic Action Plan (LEAP) Space and Questions from 1960 Still Relevant Today Economic Development • How can we utilize our dynamic system of competitive private enterprise in space, as on earth, to make newly discovered resources useful to man? • How can private enterprise and private capital make their maximum contribution? Philosophy and Policy The ultimate goal is not to impress others, or merely to explore our planetary system, but to use accessible space for the benefit of humankind. It is a goal that is not confined to a decade or a century. Nor is it confined to a single nearby destination, or to a fleeting dash to plant a flag. The idea is to begin preparing now for a future in which the material trapped in the Sun's vicinity is available for incorporation into our way of life. Dr. John Marburger, Head of the Office of Science and Technology Policy 2006 3 The Investment Premise • Just as on Earth, lunar real estate “value” is driven by location, location, location Rank Location Why Valuable 1 Peary Crater Best 1st industrial base and settlement 2 Sinus Medii Good cargo port & space elevator site 3 Largest skylights / lava tubes Best large scale settlements 4 Tsiolkovskiy crater, dark side Prime radio astronomy site 5 High helium-3 concentrations Potential high value mining 6 Lipsky Crater Space elevator site for Earth-Moon L2 7 Aristillus High Thorium concentrations • Lunar real -
User Guide to 1:250,000 Scale Lunar Maps
CORE https://ntrs.nasa.gov/search.jsp?R=19750010068Metadata, citation 2020-03-22T22:26:24+00:00Z and similar papers at core.ac.uk Provided by NASA Technical Reports Server USER GUIDE TO 1:250,000 SCALE LUNAR MAPS (NASA-CF-136753) USE? GJIDE TO l:i>,, :LC h75- lu1+3 SCALE LUNAR YAPS (Lumoalcs Feseclrch Ltu., Ottewa (Ontario) .) 24 p KC 53.25 CSCL ,33 'JIACA~S G3/31 11111 DANNY C, KINSLER Lunar Science Instltute 3303 NASA Road $1 Houston, TX 77058 Telephone: 7131488-5200 Cable Address: LUtiSI USER GUIDE TO 1: 250,000 SCALE LUNAR MAPS GENERAL In 1972 the NASA Lunar Programs Office initiated the Apollo Photographic Data Analysis Program. The principal point of this program was a detailed scientific analysis of the orbital and surface experiments data derived from Apollo missions 15, 16, and 17. One of the requirements of this program was the production of detailed photo base maps at a useable scale. NASA in conjunction with the Defense Mapping Agency (DMA) commenced a mapping program in early 1973 that would lead to the production of the necessary maps based on the need for certain areas. This paper is designed to present in outline form the neces- sary background informatiox or users to become familiar with the program. MAP FORMAT * The scale chosen for the project was 1:250,000 . The re- search being done required a scale that Principal Investigators (PI'S) using orbital photography could use, but would also serve PI'S doing surface photographic investigations. Each map sheet covers an area four degrees north/south by five degrees east/west. -
Apollo 17 Index: 70 Mm, 35 Mm, and 16 Mm Photographs
General Disclaimer One or more of the Following Statements may affect this Document This document has been reproduced from the best copy furnished by the organizational source. It is being released in the interest of making available as much information as possible. This document may contain data, which exceeds the sheet parameters. It was furnished in this condition by the organizational source and is the best copy available. This document may contain tone-on-tone or color graphs, charts and/or pictures, which have been reproduced in black and white. This document is paginated as submitted by the original source. Portions of this document are not fully legible due to the historical nature of some of the material. However, it is the best reproduction available from the original submission. Produced by the NASA Center for Aerospace Information (CASI) Preparation, Scanning, Editing, and Conversion to Adobe Portable Document Format (PDF) by: Ronald A. Wells University of California Berkeley, CA 94720 May 2000 A P O L L O 1 7 I N D E X 7 0 m m, 3 5 m m, A N D 1 6 m m P H O T O G R A P H S M a p p i n g S c i e n c e s B r a n c h N a t i o n a l A e r o n a u t i c s a n d S p a c e A d m i n i s t r a t i o n J o h n s o n S p a c e C e n t e r H o u s t o n, T e x a s APPROVED: Michael C . -
405 01.Ps, Page 1-22 @ Normalize ( 405 01.Qxd )
Geological Society of America Special Paper 405 2006 The record of impact processes on the early Earth: A review of the first 2.5 billion years Christian Koeberl† Department of Geological Sciences, University of Vienna, Althanstrasse 14, A-1090 Vienna, Austria ABSTRACT Collisions and impact processes have been important throughout the history of the solar system, including that of the Earth. Small bodies in the early solar system, the planetesimals, grew through collisions, ultimately forming the planets. The Earth started growing ca. 4.56 Ga in this way. Its early history was dominated by violent impacts and collisions, of which we only have circumstantial evidence. The Earth was still growing and had reached ~70%–80% of its present mass when at ca. 4.5 Ga a Mars- sized protoplanet collided with Earth, leading to the formation of the moon—at least according to the currently most popular hypothesis of lunar origin. After its forma- tion, the moon was subjected to intense post-accretionary bombardment between ca. 4.5 and 3.9 Ga. In addition, there is convincing evidence that the Moon experienced an interval of intense bombardment with a maximum at ca. 3.85 ± 0.05 Ga; subsequent mare plains as old as 3.7 or 3.8 Ga are preserved. It is evident that if a late heavy bom- bardment occurred on the Moon, the Earth must have been subjected to an impact flux at least as intense as that recorded on the Moon. The consequences for the Earth must have been devastating, although the exact consequences are the subject of debate (total remelting of the crust versus minimal effects on possibly emerging life forms).