An Archaean Heavy Bombardment from a Destabilized Extension of the Asteroid Belt
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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. -
Photometric Study of Two Near-Earth Asteroids in the Sloan Digital Sky Survey Moving Objects Catalog
University of North Dakota UND Scholarly Commons Theses and Dissertations Theses, Dissertations, and Senior Projects January 2020 Photometric Study Of Two Near-Earth Asteroids In The Sloan Digital Sky Survey Moving Objects Catalog Christopher James Miko Follow this and additional works at: https://commons.und.edu/theses Recommended Citation Miko, Christopher James, "Photometric Study Of Two Near-Earth Asteroids In The Sloan Digital Sky Survey Moving Objects Catalog" (2020). Theses and Dissertations. 3287. https://commons.und.edu/theses/3287 This Thesis is brought to you for free and open access by the Theses, Dissertations, and Senior Projects at UND Scholarly Commons. It has been accepted for inclusion in Theses and Dissertations by an authorized administrator of UND Scholarly Commons. For more information, please contact [email protected]. PHOTOMETRIC STUDY OF TWO NEAR-EARTH ASTEROIDS IN THE SLOAN DIGITAL SKY SURVEY MOVING OBJECTS CATALOG by Christopher James Miko Bachelor of Science, Valparaiso University, 2013 A Thesis Submitted to the Graduate Faculty of the University of North Dakota in partial fulfillment of the requirements for the degree of Master of Science Grand Forks, North Dakota August 2020 Copyright 2020 Christopher J. Miko ii Christopher J. Miko Name: Degree: Master of Science This document, submitted in partial fulfillment of the requirements for the degree from the University of North Dakota, has been read by the Faculty Advisory Committee under whom the work has been done and is hereby approved. ____________________________________ Dr. Ronald Fevig ____________________________________ Dr. Michael Gaffey ____________________________________ Dr. Wayne Barkhouse ____________________________________ Dr. Vishnu Reddy ____________________________________ ____________________________________ This document is being submitted by the appointed advisory committee as having met all the requirements of the School of Graduate Studies at the University of North Dakota and is hereby approved. -
Persistence and Origin of the Lunar Core Dynamo
Persistence and origin of the lunar core dynamo Clément Suaveta,1, Benjamin P. Weissa, William S. Cassatab, David L. Shusterc,d, Jérôme Gattaccecaa,e, Lindsey Chanf, Ian Garrick-Bethellf,g, James W. Headh, Timothy L. Grovea, and Michael D. Fulleri aDepartment of Earth, Atmospheric, and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139; bChemical Sciences Division, Lawrence Livermore National Laboratory, Livermore, CA 94550; cDepartment of Earth and Planetary Science, University of California, Berkeley, CA 94720; dBerkeley Geochronology Center, Berkeley, CA 94709; eCentre Européen de Recherche et d’Enseignement des Géosciences de l’Environnement, Centre National de la Recherche Scientifique, Université Aix-Marseille 3, 13545 Aix-en-Provence, France; fDepartment of Earth and Planetary Sciences, University of California, Santa Cruz, CA 95064; gSchool of Space Research, Kyung Hee University, Yongin 446–701, South Korea; hDepartment of Geological Sciences, Brown University, Providence, RI 02912; and iHawai’i Institute of Geophysics and Planetology, University of Hawaii at Manoa, Honolulu, HI 96822 Edited by Neta A. Bahcall, Princeton University, Princeton, NJ, and approved April 16, 2013 (received for review January 22, 2013) The lifetime of the ancient lunar core dynamo has implications for its 10017 as a constraint on the lunar dynamo. Instead, these authors power source and the mechanism of field generation. Here, we report relied on their analyses of 10049, whose subsamples were found to analyses of two 3.56-Gy-old mare basalts demonstrating that they carry a unidirectional magnetization (17) with a seemingly weak were magnetized in a stable and surprisingly intense dynamo mag- paleointensity (4–10 μT). However, our reanalysis of their data netic field of at least ∼13 μT. -
Hadean-Archean Habitability
Hadean - Early Archean: 4.4 to ~ 3.5 Ga How to build a habitable planet? Jack Hills in Australia meta-conglomerat with the oldest minerals on Earth 4.4 Ga Geological time scale 1 : Hadean 2 : Archean Quasi no rock record Rock record First cooling of magma ocean Alteration of basalt to produce serpentinite crust ~ as today on seafloor 146 142 Sm → Nd (T1/2= 103 Ma) silicate/silicate fractionation before total decay of 146Sm ⇒ < 150 Ma, done early Hadean Acasta (Canada) oldest rocks on Earth, end of Hadean, 4.01 Ga Acasta (Canada) oldest rocks on Earth, end of Hadean, 4.01 Ga Acasta (Canada) oldest rocks on Earth, end of Hadean, 4.01 Ga Zircon ages Jack Hills (Australia) meta-conglomerat Archean in age but contains very old zircons Jack Hills (Australia) meta-conglomerat Archean in age but contains very old zircons Jack Hills (Australia) meta-conglomerat Archean in age but contains very old zircons ZrSiO4 1 mm U-Pb age at 4.4 Ga Part of the grain crystalized shortly after end of magma ocean Age distribution of zircons Different dates on different zircon layers Several age populations Oldest Quartz, micas and plagioclase ∂18O in zircons = 5 to 7.4 ‰ Original magma’s = ∂18O ~ 8.5 to 9.5‰ (La/Lu)N zircons⇒(La/Lu)N of magma~ 200 = TTG magma 4.4 Gyr zircons not so different from actual zircons Granitic inclusions present in zircons Quartz, micas and plagioclase ∂18O in zircons = 5 to 7.4 ‰ Original magma’s = ∂18O ~ 8.5 to 9.5‰ (La/Lu)N zircons⇒(La/Lu)N of magma~ 200 = TTG magma 4.4 Gyr zircons not so different from actual zircons Continental -
Hungaria Asteroid Family As the Source of Aubrite Meteorites ⇑ Matija C´ Uk A, , Brett J
Icarus 239 (2014) 154–159 Contents lists available at ScienceDirect Icarus journal homepage: www.elsevier.com/locate/icarus Hungaria asteroid family as the source of aubrite meteorites ⇑ Matija C´ uk a, , Brett J. Gladman b, David Nesvorny´ c a Carl Sagan Center, SETI Institute, 189 North Bernardo Avenue, Mountain View, CA 94043, USA b Department of Physics and Astronomy, University of British Columbia, 6224 Agricultural Road, Vancouver, BC V6T 1Z1, Canada c Southwest Research Institute, 1050 Walnut St., Suite 400, Boulder, CO 80302, USA article info abstract Article history: The Hungaria asteroids are interior to the main asteroid belt, with semimajor axes between 1.8 and 2 AU, Received 27 January 2014 low eccentricities and inclinations of 16–35°. Small asteroids in the Hungaria region are dominated by a Revised 24 May 2014 collisional family associated with (434) Hungaria. The dominant spectral type of the Hungaria group is Accepted 31 May 2014 the E or X-type (Warner et al. [2009]. Icarus, 204, 172–182), mostly due to the E-type composition of Available online 12 June 2014 Hungaria and its genetic family. It is widely believed the E-type asteroids are related to the aubrite meteorites, also known as enstatite achondrites (Gaffey et al. [1992]. Icarus, 100, 95–109). Here we Keywords: explore the hypothesis that aubrites originate in the Hungaria family. In order to test this connection, Asteroids we compare model Cosmic Ray Exposure ages from orbital integrations of model meteoroids with those Asteroids, dynamics Meteorites of aubrites. We show that long CRE ages of aubrites (longest among stony meteorite groups) reflect the Planetary dynamics delivery route of meteoroids from Hungarias to Earth being different than those from main-belt asteroids. -
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Volume 46 Number 1 JAAVSO 2018 The Journal of the American Association of Variable Star Observers Optical Flares and Quasi-Periodic Pulsations on CR Draconis during Periastron Passage Upper panel: 2017-10-10-flare photon counts, time aligned with FFT spectrogram. Lower panel: FFT spectrogram shows time in UT seconds versus QPP periods in seconds. Flares cited by Doyle et al. (2018) are shown with (*). Also in this issue... • The Dwarf Nova SY Cancri and its Environs • KIC 8462852: Maria Mitchell Observatory Photographic Photometry 1922 to 1991 • Visual Times of Maxima for Short Period Pulsating Stars III • Recent Maxima of 86 Short Period Pulsating Stars Complete table of contents inside... The American Association of Variable Star Observers 49 Bay State Road, Cambridge, MA 02138, USA The Journal of the American Association of Variable Star Observers Editor John R. Percy Kosmas Gazeas Kristine Larsen Dunlap Institute of Astronomy University of Athens Department of Geological Sciences, and Astrophysics Athens, Greece Central Connecticut State University, and University of Toronto New Britain, Connecticut Toronto, Ontario, Canada Edward F. Guinan Villanova University Vanessa McBride Associate Editor Villanova, Pennsylvania IAU Office of Astronomy for Development; Elizabeth O. Waagen South African Astronomical Observatory; John B. Hearnshaw and University of Cape Town, South Africa Production Editor University of Canterbury Michael Saladyga Christchurch, New Zealand Ulisse Munari INAF/Astronomical Observatory Laszlo L. Kiss of Padua Editorial Board Konkoly Observatory Asiago, Italy Geoffrey C. Clayton Budapest, Hungary Louisiana State University Nikolaus Vogt Baton Rouge, Louisiana Katrien Kolenberg Universidad de Valparaiso Universities of Antwerp Valparaiso, Chile Zhibin Dai and of Leuven, Belgium Yunnan Observatories and Harvard-Smithsonian Center David B. -
Hungaria Asteroid Family As the Source of Aubrite Meteorites
Hungaria Asteroid Family as the Source of Aubrite Meteorites Matija Cuk´ 1, Brett J. Gladman2, David Nesvorn´y3 1Carl Sagan Center, SETI Institute 189 North Bernardo Avenue, Mountain View, CA 94043 2Department of Physics and Astronomy, University of British Columbia 6224 Agricultural Road, Vancouver, BC V6T 1Z1, Canada 3Southwest Research Institute 1050 Walnut St, Suite 400, Boulder, CO 80302 E-mail: [email protected] Re-submitted to Icarus May 23rd 2014. Manuscript Pages: 31 Figures: 6 Tables: 2 arXiv:1406.0825v1 [astro-ph.EP] 3 Jun 2014 1 Proposed Running Head: Aubrites from Hungaria Family Editorial Correspondence to: Matija Cuk´ Carl Sagan Center SETI Institute 189 N Bernardo Ave Mountain View, CA 94043 Phone: 650-810-0210 Fax: 650- E-mail: [email protected] 2 ABSTRACT: The Hungaria asteroids are interior to the main asteroid belt, with semimajor axes between 1.8 and 2 AU, low eccentricities and inclinations of 16-35 degrees. Small asteroids in the Hungaria region are dominated by a collisional family associated with (434) Hungaria. The dominant spectral type of the Hungaria group is the E or X-type (Warner et al., 2009), mostly due to the E-type composition of Hungaria and its genetic family. It is widely believed the E-type asteroids are related to the aubrite meteorites, also known as enstatite achondrites (Gaffey et al., 1992). Here we explore the hypothesis that aubrites originate in the Hungaria family. In order to test this connection, we compare model Cosmic Ray Exposure ages from orbital integrations of model meteoroids with those of aubrites. We show that long CRE ages of aubrites (longest among stony meteorite groups) reflect the delivery route of meteoroids from Hungarias to Earth being different than those from main-belt asteroids.