The Sizes and Nature of Basin Impactors on Mercury and the Moon

Total Page:16

File Type:pdf, Size:1020Kb

The Sizes and Nature of Basin Impactors on Mercury and the Moon Lunar and Planetary Science XLVIII (2017) 2704.pdf THE SIZES AND NATURE OF BASIN IMPACTORS ON MERCURY AND THE MOON. P. H. Schultz, Department of Earth, Environmental, and Planetary Sciences, Brown University, 324 Book Street, Box 1846, Providence, RI 02912; peter_schultz@brown.edu. Introduction: Oblique impacts map out different exhibit strong contrasts. An estimate for the oblique stages of crater formation across the surface and can impact crater Dantu (with an elongate central pit) on reveal the controlling independent variables. Ceres was also included. Laboratory experiments allow isolating these different Results: Mapped sculpture patterns on Mercury stages and variables, even though they cannot directly yielded the following sizes of the impacting bodies: simulate a large-scale event. One critical set of Caloris (525 km diameter), Rembrandt (115 km), variables includes impact angle and impactor size. On Beethoven (246 km), Tolstoj (197 km), Vivaldi (43 the planets, crater morphology and ejecta distribution km), Dürer (86 km), Wang Meng (36 km), and Valmki can be used to constrain the size of the impacting body, (23 km). Such sizes may seem large but are generally independent of scaling relations [1] and provide clues consistent with extrapolated scaling relations (Fig. 1a). to the origin of the inner rings of large basins [2]. Scaling relations refer to impact diameters referenced Background: At large scales, early stages of crater to the pre-impact surface, i.e., the “apparent” diameter, formation become more evident due to the reduced rather than the final post-collapse diameter. Here, the cratering efficiency [3]. For an oblique impact, rim-rim diameters of each basin was reduced by 25% surface expressions of an evolving flow field include a to account for crater enlargement by slumping and migrating source region of ejecta [4], non-circular another 25% in order to adjust to the pre-impact elements in crater shape [5,6], and downrange scours surface. Figure 1a reveals that lunar and Mercurian by the impactor [1,7]. The Imbrium Sculpture basins (and Dantu on Ceres) fall on the extrapolated illustrates each of these signatures [1]. For sufficiently scaling relation for non-porous gravity-controlled oblique angles, fragments of the impacting body begin targets after making small (but reasonable) adjustments to fail soon after first contact such that the tops and for impact speed and angle. sides of the impactor scour the surface beyond the final While the inner rings of two-ring basins are easy to crater rim. Back-extrapolated trends of the resulting recognize, the correct identification becomes grooves either converge beyond the uprange rim or problematic for multi-ring structures. For this study, it form sub-parallel sets converging far uprange. Based is assumed that the inner, oblong wrinkle ridge system on experiments and 3D hydrocode models, the width of Imbrium and the inner oblong shelf in Orientale of these grooves and scours near the uprange rim can represent the inner ring. Even then, the multi-ring be used to constrain the diameter of the impactor. This basins (Rembrandt, Orientale, and Imbrium) require a strategy yielded a diameter of the Imbrium impactor as much higher speed, much lower angle, or a different at least 250 km, along with estimates of 110 km, 100 transient diameter in order to be consistent with the km, and 45 km for Orientale, Moscoviense, and peak-ring basins in Fig.1a. If the apparent transient Schrödinger, respectively [1]. Here we extend this crater diameter for Imbrium were placed between the approach to basins on other bodies, compare the Montes Alpes and oblong massif ring delineated by derived impactor diameters with the measured interior Montes Recti-Pico-Pito, the scaling relation would peak ring diameters, and assess predictions based on hold. For Orientale, the a working diameter would scaling relations. The onset transition in interior correspond to a position between Inner and Outer morphologies (such as central peaks and rings) not Rooke Mountains. only depends on gravity but also impact speed [8,9,10]. The derived impactor diameter also can be Consequently, such features should be expressed in the compared with the inner ring diameter (Figure 1b). An scaling relations as well. average ring diameter is not assumed; rather, the Selected Basins: By definition, such a strategy can physically relevant diameter is orthogonal to the include only those craters formed by oblique trajectory, as from inferred from the morphologic trajectories with clearly expressed impactor signatures. signatures (ejecta and crater structure). In general, the Nevertheless, this subset establishes a benchmark for ring-impactor diameter ratio (DIR/a) is about 2, but interpreting higher angle impacts. Stereographic impactors larger than about 100 km are consistently projections centered on selected basins on Mercury above the extrapolated linear trend for smaller provided the base maps for determination of impactors. downrange groove trends. The selected basins Discussion: The correlation between the inner ring included: Caloris (1250 km diameter), Rembrandt (720 diameter and observationally determined impactor km), Beethoven (640 km), Tolstoj (490 km), Vivaldi diameter (Fig. 1b) is consistent with the “footprint” (210 km), Dürer (190 km), Wang Meng (160 km), and model of inner ring formation [2,11]. In this model, Valmki (97 km). The morphologies of these basins the inner ring is related to dynamic uplift of the Lunar and Planetary Science XLVIII (2017) 2704.pdf displaced-downward crust. For an oblique impact at Fassett, C. I. et al. (2012), JGR 117, E00L08, doi: 30°, the downward-directed peak pressure is reduced 10.1029/2012JE004154; [13] Ernst, C. M. et al. by a factor of four. This reduced pressure increases the (2016), LPSC 47, #1374; [14] Barnouin, O. et al. role of target strength at depth, even at speeds less than (2015), LPSC 46 #2672; [15] Le Feuvre, M. and 15 km/s. At higher speeds (>20 km/s), energy plays a Wieczorek, M. A. (2011), Icarus 214, 1-20; [16] greater role and results in loss of expression of the Barlow, N. G., and T. L. Bradley (1990), Icarus 87, downward-displaced zone and the formation of central 156–179; [17] Robbins, S. J. and Hynek, B.M. (2012), peaks. In laboratory experiments, the ratio of the edge JGR 117, E06001, doi:10.1029/2011JE003967. of the downward-displaced pit is also nearly constant as a function of (v sinθ), even though the diameter and 2.0# 100# depth of the crater changes. But it also depends on the MercUry# Moon# a#–#ReMbrandt##(80#kM/s,#30°)# 1#–#Schrödinger#(8#kM/s#@#15°)*# impedance ratio between the impactor and target b#–Vivaldi#(30#kM/s,#30°)# 2#–#Moscoviense#(15#km/s#@#30°)*# 50# c#–#Dürer#(15#km/s,#30°)# 3#–#Orientale#(25#kM/s#@#30°)*# (Ip/It). Hence, the upward offsets for the inner rings of d#–#ValMke#(15#km/s,#30°)# 4#–#ImbriUM#(25#kM/s#@#30°)*# Schrödinger, Orientale, Rembrandt, and Imbrium in e#–#Wang#Meng#(15km/s,#30°)# f#–#Tolstoj#(15#km/s,#30°)**# 20# /#a)# D/2r# Fig. 1b could represent an effect of differentiated g#–#Beethoven#(15#kM/s,#30°)## A# asteroids with a higher (Ip/It). Conversely, values of 1.0# h#–#Caloris#15#km/s,#30°)## 10# low (Ip/It), such as a cometary impact, should result in Log#(D 1# a# 5# smaller and poorly expressed central rings. z# b# 3# c#e# 4#MRB# Implications: First, lower speed impactors may be 2# Ceres# d# f# g# 2# responsible for the apparent excess of the 200-350 km z#–#Dantu#(5#km/s,#30°)## h# diameter basins on Mercury, consistent with the observed excess of basins per unit area in this size !6# !5# !4# !3# !2# !1# range relative to the Moon [12]. Second, most craters 2 post-dating the Late Heavy Bombardment on Mercury Log#[π2#=##gr/(vsinθ) ]# (99%) and the Moon (90%) were formed at speeds > Fig. 1a: Apparent crater diameter (DA) scaled by impactor 15 km/s, consistent with the greater abundance of diameter (a) as a function of the pi-2 scaling relation [3]. central peaks. But certain craters with small, broken Impactor diameters were determined by the convergence of inner rings (e.g., Eminescu) may represent comets downrange grooves/scours following [1]. Assumed values impacting at the lower end of expected impact speeds. are shown in the legend. The crater diameter was adjusted The unusual Hokusai crater [13, 14] could represent an for the target/projectile density ratio. It is assumed that low- unusually slow cometary impact (<10 km/s). Third, speed undifferentiated asteroids formed the two-ring basins central pit craters represent an extension of the on Mercury, in contrast with larger multi-ring basins (except Tolstoj, which is consistent with a comet). footprint model for smaller bodies where impactor momentum, penetration depths, and dynamic response 3.00$ were insufficient to produce an uplifted ring but did 4$ produce downward displacement. This is consistent 2$ with oblong central pits in oblique impacts and double a$ pits in simultaneous impacts [8]. Fourth, the bi-modal 1$ 3$ distribution of impact speeds on Mars [15] would 2.00$ b$ c$ produce a population of craters of the same size with e$ central peaks, central pits, and central rings in the same d$ terrains [16, 17]. References: [1] Schultz, P.H. and Crawford, D.A. (2016), Nature 535, 391-394; [2] Schultz, P.H. (2016), 1.00$ LPSC 47, #2931; [3] Holsapple, K.A. and Schmidt, R. Log$(Inner$Ring$Diameter)$ M. (1987), JGR 92, 6350-6376; [4] Anderson, J. L. B. (2004), MAPS 39,303-320; [5] Gault, D. E., and 1.00$ 2.00$ 3.0$ Wedekind, J. A. (1978), Proc. Lunar Planet. Sci. Log$(Impactor$Diameter)$ Conf., 9th, 3843–3875; [6] Schultz, P.
Recommended publications
  • Eminescu and the Transition to Peak-Ring Basins on Mercury
    41st Lunar and Planetary Science Conference (2010) 1263.pdf EMINESCU AND THE TRANSITION TO PEAK-RING BASINS ON MERCURY. S. C. Schon,1 J. W. Head,1 L. M. Prockter2, and the MESSENGER Science Team.3 1Dept. of Geological Sciences, Brown University, Providence, RI 02906 USA; 2JHU/APL, Laurel, MD; 3http://messenger.jhuapl.edu/who_we_are/science_team.html. Introduction: The MESSENGER [1] flybys have yielded a range of new scientific findings for Mercury [2] including evidence of embayment relationships indicative of volcanic plains activity [3,4] and an im- proved size estimate for the Caloris basin [5]. These new data reveal a broad continuum of Mercurian crater morphologies [6] in greater detail than prior studies that relied on Mariner 10 or Earth-based radar observa- tions [7]. This study focuses on mapping the interior deposits of Eminescu, a central peak-ring basin, and is part of a larger comparative analysis of transitional crater morphologies observed on Mercury and the Moon in new data sets [8]. Impacts on Mercury occur at much higher veloci- ties than lunar impacts and correspondingly generate more impact melt. Cintala [9] estimated that for a given projectile, the velocity difference will lead to twice as much impact melt on Mercury than on the Moon. Here we examine images at ~150 m/pixel reso- Figure 1: Eminescu Crater, ~125-km in diameter (10.8°N, lution of the fresh impact crater Eminescu to document 114.1°E), imaged during the first MESSENGER flyby. the nature of fresh crater interiors on Mercury at the transition from complex to peak-ring morphology.
    [Show full text]
  • Mercury's Low-Reflectance Material: Constraints from Hollows
    Mercury’s low-reflectance material: Constraints from hollows Rebecca Thomas, Brian Hynek, David Rothery, Susan Conway To cite this version: Rebecca Thomas, Brian Hynek, David Rothery, Susan Conway. Mercury’s low-reflectance material: Constraints from hollows. Icarus, Elsevier, 2016, 277, pp.455-465. 10.1016/j.icarus.2016.05.036. hal-02271739 HAL Id: hal-02271739 https://hal.archives-ouvertes.fr/hal-02271739 Submitted on 27 Aug 2019 HAL is a multi-disciplinary open access L’archive ouverte pluridisciplinaire HAL, est archive for the deposit and dissemination of sci- destinée au dépôt et à la diffusion de documents entific research documents, whether they are pub- scientifiques de niveau recherche, publiés ou non, lished or not. The documents may come from émanant des établissements d’enseignement et de teaching and research institutions in France or recherche français ou étrangers, des laboratoires abroad, or from public or private research centers. publics ou privés. Accepted Manuscript Mercury’s Low-Reflectance Material: Constraints from Hollows Rebecca J. Thomas , Brian M. Hynek , David A. Rothery , Susan J. Conway PII: S0019-1035(16)30246-9 DOI: 10.1016/j.icarus.2016.05.036 Reference: YICAR 12084 To appear in: Icarus Received date: 23 February 2016 Revised date: 9 May 2016 Accepted date: 24 May 2016 Please cite this article as: Rebecca J. Thomas , Brian M. Hynek , David A. Rothery , Susan J. Conway , Mercury’s Low-Reflectance Material: Constraints from Hollows, Icarus (2016), doi: 10.1016/j.icarus.2016.05.036 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript.
    [Show full text]
  • Impact Melt Emplacement on Mercury
    Western University Scholarship@Western Electronic Thesis and Dissertation Repository 7-24-2018 2:00 PM Impact Melt Emplacement on Mercury Jeffrey Daniels The University of Western Ontario Supervisor Neish, Catherine D. The University of Western Ontario Graduate Program in Geology A thesis submitted in partial fulfillment of the equirr ements for the degree in Master of Science © Jeffrey Daniels 2018 Follow this and additional works at: https://ir.lib.uwo.ca/etd Part of the Geology Commons, Physical Processes Commons, and the The Sun and the Solar System Commons Recommended Citation Daniels, Jeffrey, "Impact Melt Emplacement on Mercury" (2018). Electronic Thesis and Dissertation Repository. 5657. https://ir.lib.uwo.ca/etd/5657 This Dissertation/Thesis is brought to you for free and open access by Scholarship@Western. It has been accepted for inclusion in Electronic Thesis and Dissertation Repository by an authorized administrator of Scholarship@Western. For more information, please contact wlswadmin@uwo.ca. Abstract Impact cratering is an abrupt, spectacular process that occurs on any world with a solid surface. On Earth, these craters are easily eroded or destroyed through endogenic processes. The Moon and Mercury, however, lack a significant atmosphere, meaning craters on these worlds remain intact longer, geologically. In this thesis, remote-sensing techniques were used to investigate impact melt emplacement about Mercury’s fresh, complex craters. For complex lunar craters, impact melt is preferentially ejected from the lowest rim elevation, implying topographic control. On Venus, impact melt is preferentially ejected downrange from the impact site, implying impactor-direction control. Mercury, despite its heavily-cratered surface, trends more like Venus than like the Moon.
    [Show full text]
  • Geologic Map of the Victoria Quadrangle (H02), Mercury
    H01 - Borealis Geologic Map of the Victoria Quadrangle (H02), Mercury 60° Geologic Units Borea 65° Smooth plains material 1 1 2 3 4 1,5 sp H05 - Hokusai H04 - Raditladi H03 - Shakespeare H02 - Victoria Smooth and sparsely cratered planar surfaces confined to pools found within crater materials. Galluzzi V. , Guzzetta L. , Ferranti L. , Di Achille G. , Rothery D. A. , Palumbo P. 30° Apollonia Liguria Caduceata Aurora Smooth plains material–northern spn Smooth and sparsely cratered planar surfaces confined to the high-northern latitudes. 1 INAF, Istituto di Astrofisica e Planetologia Spaziali, Rome, Italy; 22.5° Intermediate plains material 2 H10 - Derain H09 - Eminescu H08 - Tolstoj H07 - Beethoven H06 - Kuiper imp DiSTAR, Università degli Studi di Napoli "Federico II", Naples, Italy; 0° Pieria Solitudo Criophori Phoethontas Solitudo Lycaonis Tricrena Smooth undulating to planar surfaces, more densely cratered than the smooth plains. 3 INAF, Osservatorio Astronomico di Teramo, Teramo, Italy; -22.5° Intercrater plains material 4 72° 144° 216° 288° icp 2 Department of Physical Sciences, The Open University, Milton Keynes, UK; ° Rough or gently rolling, densely cratered surfaces, encompassing also distal crater materials. 70 60 H14 - Debussy H13 - Neruda H12 - Michelangelo H11 - Discovery ° 5 3 270° 300° 330° 0° 30° spn Dipartimento di Scienze e Tecnologie, Università degli Studi di Napoli "Parthenope", Naples, Italy. Cyllene Solitudo Persephones Solitudo Promethei Solitudo Hermae -30° Trismegisti -65° 90° 270° Crater Materials icp H15 - Bach Australia Crater material–well preserved cfs -60° c3 180° Fresh craters with a sharp rim, textured ejecta blanket and pristine or sparsely cratered floor. 2 1:3,000,000 ° c2 80° 350 Crater material–degraded c2 spn M c3 Degraded craters with a subdued rim and a moderately cratered smooth to hummocky floor.
    [Show full text]
  • Back Matter (PDF)
    Index Page numbers in italic denote Figures. Page numbers in bold denote Tables. ‘a’a lava 15, 82, 86 Belgica Rupes 272, 275 Ahsabkab Vallis 80, 81, 82, 83 Beta Regio, Bouguer gravity anomaly Aino Planitia 11, 14, 78, 79, 83 332, 333 Akna Montes 12, 14 Bhumidevi Corona 78, 83–87 Alba Mons 31, 111 Birt crater 378, 381 Alba Patera, flank terraces 185, 197 Blossom Rupes fold-and-thrust belt 4, 274 Albalonga Catena 435, 436–437 age dating 294–309 amors 423 crater counting 296, 297–300, 301, 302 ‘Ancient Thebit’ 377, 378, 388–389 lobate scarps 291, 292, 294–295 anemone 98, 99, 100, 101 strike-slip kinematics 275–277, 278, 284 Angkor Vallis 4,5,6 Bouguer gravity anomaly, Venus 331–332, Annefrank asteroid 427, 428, 433 333, 335 anorthosite, lunar 19–20, 129 Bransfield Rift 339 Antarctic plate 111, 117 Bransfield Strait 173, 174, 175 Aphrodite Terra simple shear zone 174, 178 Bouguer gravity anomaly 332, 333, 335 Bransfield Trough 174, 175–176 shear zones 335–336 Breksta Linea 87, 88, 89, 90 Apollinaris Mons 26,30 Brumalia Tholus 434–437 apollos 423 Arabia, mantle plumes 337, 338, 339–340, 342 calderas Arabia Terra 30 elastic reservoir models 260 arachnoids, Venus 13, 15 strike-slip tectonics 173 Aramaiti Corona 78, 79–83 Deception Island 176, 178–182 Arsia Mons 111, 118, 228 Mars 28,33 Artemis Corona 10, 11 Caloris basin 4,5,6,7,9,59 Ascraeus Mons 111, 118, 119, 205 rough ejecta 5, 59, 60,62 age determination 206 canali, Venus 82 annular graben 198, 199, 205–206, 207 Canary Islands flank terraces 185, 187, 189, 190, 197, 198, 205 lithospheric flexure
    [Show full text]
  • Jack Wright1, David A. Rothery1, Matt R. Balme1 and Susan J. Conway2
    Late-stage effusive volcanism on Mercury: Evidence from Mansurian impact basins Jack Wright1, David A. Rothery1, Matt R. Balme1 and Susan J. Conway2 1The Open University, Milton Keynes, MK7 6AA, UK Email: jack.wright@open.ac.uk 2LPG Nantes - UMR CNRS 6112 Université de Nantes, France Introduction Young, post-impact volcanism Fig. 1. Time systems of Mercury and ? Widespread Volcanism ? conventional absolute model ages. We are looking for geological evidence for volcanism in Mansurian impact basins Tolstojan Tolstojan [1] (>100 km). This will tell us about how plains volcanism ended on Mercury Calorian during an era of global cooling and contraction [2]. Within the Mansurian, we Pre- Hermean predict that older, larger basins host more volcanism than younger, smaller ones. Kuiperian MANSURIAN System We expect there came a time when impacts could no longer liberate magma from Mercury's interior, marking the end of effusive volcanism. Time before 4.5 4.0 3.5 3.0 2.5 2.0 1.5 1.0 0.5 0.0 present (Ga) Colour Boundaries Pyroclastics & Edifice Shield volcano talk tomorrow in Waterway 1 @ 10.00 am! 18°E 20°E 22°E 54°E 56°E 58°E 52°E 56°E 60°E 120°E 122°E 124°E 123°E A B C A B D 1000 34°S ± 800 30°N ± 600 ± 2020 kmkm 400 8°S ± ± 200 14°S 34°S 0 C 0 5 10 15 20 25 30 relative relative elevation m / 34°S 26°N ± A distance along profile / km A' 10°S 2020 kmkm 200200 kmkm 100100 kmkm 36°S 123°E 16°S -5 km Mercury global topography +4 km 100100 kmkm 100100 kmkm Fig.
    [Show full text]
  • Templeton's Peace Trent Devell Hudley University of Texas at El Paso, Tdhudley@Miners.Utep.Edu
    University of Texas at El Paso DigitalCommons@UTEP Open Access Theses & Dissertations 2009-01-01 Templeton's Peace Trent Devell Hudley University of Texas at El Paso, tdhudley@miners.utep.edu Follow this and additional works at: https://digitalcommons.utep.edu/open_etd Part of the American Literature Commons, Literature in English, North America Commons, and the Modern Literature Commons Recommended Citation Hudley, Trent Devell, "Templeton's Peace" (2009). Open Access Theses & Dissertations. 285. https://digitalcommons.utep.edu/open_etd/285 This is brought to you for free and open access by DigitalCommons@UTEP. It has been accepted for inclusion in Open Access Theses & Dissertations by an authorized administrator of DigitalCommons@UTEP. For more information, please contact lweber@utep.edu. TEMPLETON’S PEACE TRENT D. HUDLEY Department of Creative Writing APPROVED: Daniel Chacón, MFA, Committee Chair Johnny Payne, Ph.D. Mimi Gladstein, Ph.D. Patricia D. Witherspoon, Ph.D. Dean of the Graduate School Copyright © by Trent Hudley May 2009 Dedication To everyone I’ve ever hurt TEMPLETON’S PEACE by TRENT D. HUDLEY THESIS Presented to the Faculty of the Graduate School of The University of Texas at El Paso in Partial Fulfillment of the Requirements for the Degree of MASTER OF FINE ARTS Department of Creative Writing THE UNIVERSITY OF TEXAS AT EL PASO May 2009 Acknowledgements First I would like to thank my parents, Darrold and Majorie Hudley for their continued support in all that I have done. They have been there for me throughout everything whether it was for my accomplishments or things less noble. I owe them my heart.
    [Show full text]
  • 2D Mercury Crater Wordsearch V2
    3/24/2019 Word Search Generator :: Create your own printable word find worksheets @ A to Z Teacher Stuff MAKE YOUR OWN WORKSHEETS ONLINE @ WWW.ATOZTEACHERSTUFF.COM NAME:_______________________________ DATE:_____________ Craters on Mercury SICINIMODFIQPVMRQSLJ BEETHOVEN MICHELANGELO BLTVPTSDUOMRCIPDRAEN BYRON RAPHAEL YAPVWYPXSEHAUEHSEVDI CUNNINGHAM SAVAGE RRZAYRKFJROGNIGSNAIA DAMER SHAKESPEARE ORTNPIVOCDTJNRRSKGSW DOMINICI SVEINSDOTTIR NOMGETIKLKEUIAAGLEYT DRISCOLL TOLSTOI PCLOLTVLOEPSNDPNUMQK ELLINGTON VANGOGH YHEGLOAAEIGEGAHQAPRR FAULKNER VIEIRADASILVA NANHIDLNTNNNHSAOFVLA HEMINGWAY VIVALDI VDGYNSDGGMNGAIEDMRAM HOLST GALQGNIEBIMOMLLCNEZG HOMER VMESTIWWKWCANVEKLVRU IMHOTEP ZELTOEPSBOAWMAUHKCIS IZQUIERDO JRQGNVMODREIUQZICDTH JOPLIN SHAKESPEARETOLSTOIOX KIPLING BBCZWAQSZRSLPKOJHLMA LANGE SFRLLOCSIRDIYGSSSTQT LARROCHA FKUIDTISIYYFAIITRODE LENGLE NILPOJHEMINGWAYEGXLM LENNON BEETHOVENRYSKIPLINGV MARKTWAIN 1/2 Mercury Craters: Famous Writers, Artists, and Composers: Location and Sizes Beethoven: Ludwig van Beethoven (1770−1827). German composer and pianist. 20.9°S, 124.2°W; Diameter = 630 km. Byron: Lord Byron (George Byron) (1788−1824). British poet and politician. 8.4°S, 33°W; Diameter = 106.6 km. Cunningham: Imogen Cunningham (1883−1976). American photographer. 30.4°N, 157.1°E; Diameter = 37 km. Damer: Anne Seymour Damer (1748−1828). English sculptor. 36.4°N, 115.8°W; Diameter = 60 km. Dominici: Maria de Dominici (1645−1703). Maltese painter, sculptor, and Carmelite nun. 1.3°N, 36.5°W; Diameter = 20 km. Driscoll: Clara Driscoll (1861−1944). American glass designer. 30.6°N, 33.6°W; Diameter = 30 km. Ellington: Edward Kennedy “Duke” Ellington (1899−1974). American composer, pianist, and jazz orchestra leader. 12.9°S, 26.1°E; Diameter = 216 km. Faulkner: William Faulkner (1897−1962). American writer and Nobel Prize laureate. 8.1°N, 77.0°E; Diameter = 168 km. Hemingway: Ernest Hemingway (1899−1961). American journalist, novelist, and short-story writer. 17.4°N, 3.1°W; Diameter = 126 km.
    [Show full text]
  • ARCA, Nr. 2 / 2020
    nr. 2 (359), 2020 revistă lunară de literatură, eseu, arte vizuale, muzică, fondată în februarie 1990 la Arad Redactor-şef fondator: Vasile Dan Editor: CONSILIUL JUDEŢEAN ARAD prin CENTRUL CULTURAL JUDEŢEAN ARAD Apare sub egida Uniunii Scriitorilor din România Anul XXXI, nr. 2 (359), 2020 REDACŢIA: Romulus Bucur (redactor-şef adjunct), Ioan Matiuţ, Carmen Neamţu, Andrei Mocuţa, Onisim Colta (prezentare artistică), Călin Chendea (DTP, design, web development şi administrare site), Horia Ungureanu (corectură) REDACTORI ASOCIAŢI: Lajos Nótáros, Gheorghe Schwartz, Ciprian Vălcan ADRESA: Bulevardul Revoluţiei, 103, 310122 Arad, România www.uniuneascriitorilorarad.ro/revistaarca e-mail: revista_arca_arad@yahoo.com Revista „Arca” este membră a Asociaţiei Revistelor, Imprimeriilor şi Editurilor Literare (A.R.I.E.L.), asociaţie cu statut juridic, recunoscută de către Ministerul Culturii. I.S.S.N. 1221-5104 Tipărit la TRINOM SRL Arad Pe coperta I: Onisim Colta, Arca cu manuscrise (detaliu) Responsabilitatea opiniilor, ideilor şi atitudinilor exprimate în articolele publicate în „Arca” revine exclusiv autorilor lor. Sumar JURNAL Vasile Dan Cum am ratat sfîrşitul lumii ...................................................................7 CRONICA LITERARĂ Lucia Cuciureanu De la o problemă la alta (despre Gheorghe Schwartz) .............................. 23 Maria Niţu Psalmi moderni (despre Costel Stancu) .................................................... 28 Andrei Mocuța Game. Set. Meci: un schimb poetic de mingi (despre Claus Ankersen & Andrei Zbîrnea)...............................................
    [Show full text]
  • MESSENGER Reveals Mercury in New Detail 16 January 2008
    MESSENGER Reveals Mercury in New Detail 16 January 2008 It is already clear that MESSENGER’s superior camera will tell us much that could not be resolved even on the side of Mercury viewed by Mariner’s vidicon camera in the mid-1970s. This MESSENGER image was taken from a distance of about18,000 kilometers (11,000 miles), about 56 minutes before the spacecraft's closest encounter with Mercury. It shows a region roughly 500 kilometers (300 miles) across, and craters as small as 1 kilometer (0.6 mile) can be seen in this image. Source: JHU/APL Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington As MESSENGER approached Mercury on January 14, 2008, the spacecraft’s Narrow-Angle Camera on the Mercury Dual Imaging System (MDIS) instrument captured this view of the planet’s rugged, cratered landscape illuminated obliquely by the Sun. The large, shadow-filled, double ringed crater to the upper right was glimpsed by Mariner 10 more than three decades ago and named Vivaldi, after the Italian composer. Its outer ring has a diameter of about 200 kilometers (about 125 miles). MESSENGER’s modern camera has revealed detail that was not well seen by Mariner 10, including the broad ancient depression overlapped by the lower-left part of the Vivaldi crater. The MESSENGER science team is in the process of evaluating later images snapped from even closer range showing features on the side of Mercury never seen by Mariner 10. 1 / 2 APA citation: MESSENGER Reveals Mercury in New Detail (2008, January 16) retrieved 3 October 2021 from https://phys.org/news/2008-01-messenger-reveals-mercury.html This document is subject to copyright.
    [Show full text]
  • Cambridge University Press 978-1-107-15445-2 — Mercury Edited by Sean C
    Cambridge University Press 978-1-107-15445-2 — Mercury Edited by Sean C. Solomon , Larry R. Nittler , Brian J. Anderson Index More Information INDEX 253 Mathilde, 196 BepiColombo, 46, 109, 134, 136, 138, 279, 314, 315, 366, 403, 463, 2P/Encke, 392 487, 488, 535, 544, 546, 547, 548–562, 563, 564, 565 4 Vesta, 195, 196, 350 BELA. See BepiColombo: BepiColombo Laser Altimeter 433 Eros, 195, 196, 339 BepiColombo Laser Altimeter, 554, 557, 558 gravity assists, 555 activation energy, 409, 412 gyroscope, 556 adiabat, 38 HGA. See BepiColombo: high-gain antenna adiabatic decompression melting, 38, 60, 168, 186 high-gain antenna, 556, 560 adiabatic gradient, 96 ISA. See BepiColombo: Italian Spring Accelerometer admittance, 64, 65, 74, 271 Italian Spring Accelerometer, 549, 554, 557, 558 aerodynamic fractionation, 507, 509 Magnetospheric Orbiter Sunshield and Interface, 552, 553, 555, 560 Airy isostasy, 64 MDM. See BepiColombo: Mercury Dust Monitor Al. See aluminum Mercury Dust Monitor, 554, 560–561 Al exosphere. See aluminum exosphere Mercury flybys, 555 albedo, 192, 198 Mercury Gamma-ray and Neutron Spectrometer, 554, 558 compared with other bodies, 196 Mercury Imaging X-ray Spectrometer, 558 Alfvén Mach number, 430, 433, 442, 463 Mercury Magnetospheric Orbiter, 552, 553, 554, 555, 556, 557, aluminum, 36, 38, 147, 177, 178–184, 185, 186, 209, 559–561 210 Mercury Orbiter Radio Science Experiment, 554, 556–558 aluminum exosphere, 371, 399–400, 403, 423–424 Mercury Planetary Orbiter, 366, 549, 550, 551, 552, 553, 554, 555, ground-based observations, 423 556–559, 560, 562 andesite, 179, 182, 183 Mercury Plasma Particle Experiment, 554, 561 Andrade creep function, 100 Mercury Sodium Atmospheric Spectral Imager, 554, 561 Andrade rheological model, 100 Mercury Thermal Infrared Spectrometer, 366, 554, 557–558 anorthosite, 30, 210 Mercury Transfer Module, 552, 553, 555, 561–562 anticline, 70, 251 MERTIS.
    [Show full text]
  • PDF (V. 73:11 December 9, 1971)
    Bah, Humbug! IlIFORNIA Copvright 197] by the Associated Students of tl,,,. CaliforniaTechInstitute of Technology. Incorppratf'd. Volume LXXIII Pasadena, California, Thursday, December 9, 1971 Number 11 New ASCIT Funding 1mplemented:Controls Frosh Win Cold Mudeo: Now In Your Hands Juniors Beat All Runners by Norris Krueger by Channon Price everyone's choice for Mudeo prin­ There have been serious ques­ Was it ever really in doubt? cess. The Juniors also decided to tions raised concerning the oper­ What made this year's Mudeo name the first Mudeo Queen this ation of students marking how they more interesting than all of its year to go along with the othe; want their dues spent. First, we equally curious parts was the way precedent setting innovations. encourage people to support acti­ the Juniors managed to lull the The afternoon was cool and vities that they will (or might) Sophomores into a relative state of overcast and the forecast high was participate in and to support other quietude, all the while, of course, for 60 0, so of course the pit was in things they feel are worthwhile. scheming to award the Frosh a last­ perfect condition. The frosh fin­ (For example, you don't have to be second victory and beat a hasty ished the preparations by destoning a jock to support athletic awards.) retreat to a waiting, warmed-up the pit, and then readied themselves This in NO way limits the range of escape vehicle. for the challenge of the sopho­ activities you can take part in, (For For a time it looked as though mores.
    [Show full text]