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Kotsyurbenko OR, Kompanichenko VN, Brouchkov AV, Khrunyk YY, Karlov SP, Sorokin VV, Skladnev DA. Different Scenarios for the Origin and the Subsequent Succession of a Hypothetical Microbial Community in the Cloud Layer of Venus. ASTROBIOLOGY 2024; 24:423-441. [PMID: 38563825 DOI: 10.1089/ast.2022.0117] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/04/2024]
Abstract
The possible existence of a microbial community in the venusian clouds is one of the most intriguing hypotheses in modern astrobiology. Such a community must be characterized by a high survivability potential under severe environmental conditions, the most extreme of which are very low pH levels and water activity. Considering different scenarios for the origin of life and geological history of our planet, a few of these scenarios are discussed in the context of the origin of hypothetical microbial life within the venusian cloud layer. The existence of liquid water on the surface of ancient Venus is one of the key outstanding questions influencing this possibility. We link the inherent attributes of microbial life as we know it that favor the persistence of life in such an environment and review the possible scenarios of life's origin and its evolution under a strong greenhouse effect and loss of water on Venus. We also propose a roadmap and describe a novel methodological approach for astrobiological research in the framework of future missions to Venus with the intent to reveal whether life exists today on the planet.
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Affiliation(s)
- Oleg R Kotsyurbenko
- Higher School of Ecology, Yugra State University, Khanty-Mansiysk, Russia
- Network of Researchers on the Chemical Evolution of Life, Leeds, United Kingdom
| | - Vladimir N Kompanichenko
- Network of Researchers on the Chemical Evolution of Life, Leeds, United Kingdom
- Institute for Complex Analysis of Regional Problems RAS, Birobidzhan, Russia
| | | | - Yuliya Y Khrunyk
- Department of Heat Treatment and Physics of Metal, Ural Federal University, Ekaterinburg, Russia
| | - Sergey P Karlov
- Faculty of Mechanical Engineering, Moscow Polytechnic University, Moscow, Russia
| | - Vladimir V Sorokin
- Research Center of Biotechnology of the Russian Academy of Sciences, Winogradsky Institute of Microbiology, Moscow, Russia
| | - Dmitry A Skladnev
- Network of Researchers on the Chemical Evolution of Life, Leeds, United Kingdom
- Research Center of Biotechnology of the Russian Academy of Sciences, Winogradsky Institute of Microbiology, Moscow, Russia
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2
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Wood BE, Hess P, Lustig‐Yaeger J, Gallagher B, Korwan D, Rich N, Stenborg G, Thernisien A, Qadri SN, Santiago F, Peralta J, Arney GN, Izenberg NR, Vourlidas A, Linton MG, Howard RA, Raouafi NE. Parker Solar Probe Imaging of the Night Side of Venus. GEOPHYSICAL RESEARCH LETTERS 2022; 49:e2021GL096302. [PMID: 35864851 PMCID: PMC9286398 DOI: 10.1029/2021gl096302] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/22/2021] [Revised: 11/23/2021] [Accepted: 11/29/2021] [Indexed: 05/07/2023]
Abstract
We present images of Venus from the Wide-Field Imager for Parker Solar Probe (WISPR) telescope on board the Parker Solar Probe (PSP) spacecraft, obtained during PSP's third and fourth flybys of Venus on 2020 July 11 and 2021 February 20, respectively. Thermal emission from the surface is observed on the night side, representing the shortest wavelength observations of this emission ever, the first detection of the Venusian surface by an optical telescope observing below 0.8 μm. Consistent with previous observations at 1 μm, the cooler highland areas are fainter than the surrounding lowlands. The irradiances measured by WISPR are consistent with model predictions assuming a surface temperature of T = 735 K. In addition to the thermal emission, the WISPR images also show bright nightglow emission at the limb, and we compare the WISPR intensities with previous spectroscopic measurements of the molecular oxygen nightglow lines from Venus Express.
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Affiliation(s)
- Brian E. Wood
- Naval Research LaboratorySpace Science DivisionWashingtonDCUSA
| | - Phillip Hess
- Naval Research LaboratorySpace Science DivisionWashingtonDCUSA
| | | | | | - Daniel Korwan
- Naval Research LaboratoryRemote Sensing DivisionWashingtonDCUSA
| | - Nathan Rich
- Naval Research LaboratorySpace Science DivisionWashingtonDCUSA
| | | | | | - Syed N. Qadri
- Naval Research LaboratoryRemote Sensing DivisionWashingtonDCUSA
| | | | | | | | - Noam R. Izenberg
- The Johns Hopkins University Applied Physics LaboratoryLaurelMDUSA
| | | | - Mark G. Linton
- Naval Research LaboratorySpace Science DivisionWashingtonDCUSA
| | | | - Nour E. Raouafi
- The Johns Hopkins University Applied Physics LaboratoryLaurelMDUSA
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Production of ammonia makes Venusian clouds habitable and explains observed cloud-level chemical anomalies. Proc Natl Acad Sci U S A 2021; 118:2110889118. [PMID: 34930842 PMCID: PMC8719887 DOI: 10.1073/pnas.2110889118] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/11/2021] [Indexed: 11/18/2022] Open
Abstract
This research provides a transformative hypothesis for the chemistry of the atmospheric cloud layers of Venus while reconciling decades-long atmosphere anomalies. Our model predicts that the clouds are not entirely made of sulfuric acid, but are partially composed of ammonium salt slurries, which may be the result of biological production of ammonia in cloud droplets. As a result, the clouds are no more acidic than some extreme terrestrial environments that harbor life. Life could be making its own environment on Venus. The model’s predictions for the abundance of gases in Venus’ atmosphere match observation better than any previous model, and are readily testable. The atmosphere of Venus remains mysterious, with many outstanding chemical connundra. These include the unexpected presence of ∼10 ppm O2 in the cloud layers, an unknown composition of large particles in the lower cloud layers, and hard to explain measured vertical abundance profiles of SO2 and H2O. We propose a hypothesis for the chemistry in the clouds that largely addresses all of the above anomalies. We include ammonia (NH3), a key component that has been tentatively detected both by the Venera 8 and Pioneer Venus probes. NH3 dissolves in some of the sulfuric acid cloud droplets, effectively neutralizing the acid and trapping dissolved SO2 as ammonium sulfite salts. This trapping of SO2 in the clouds, together with the release of SO2 below the clouds as the droplets settle out to higher temperatures, explains the vertical SO2 abundance anomaly. A consequence of the presence of NH3 is that some Venus cloud droplets must be semisolid ammonium salt slurries, with a pH of ∼1, which matches Earth acidophile environments, rather than concentrated sulfuric acid. The source of NH3 is unknown but could involve biological production; if so, then the most energy-efficient NH3-producing reaction also creates O2, explaining the detection of O2 in the cloud layers. Our model therefore predicts that the clouds are more habitable than previously thought, and may be inhabited. Unlike prior atmospheric models, ours does not require forced chemical constraints to match the data. Our hypothesis, guided by existing observations, can be tested by new Venus in situ measurements.
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Mogul R, Limaye SS, Lee YJ, Pasillas M. Potential for Phototrophy in Venus' Clouds. ASTROBIOLOGY 2021; 21:1237-1249. [PMID: 34569810 DOI: 10.1089/ast.2021.0032] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
We show that solar irradiances calculated across Venus' clouds support the potential for Earth-like phototrophy and that treatment of Venus' aerosols containing neutralized sulfuric acid favor a habitable zone. The phototrophic potential of Venus' atmosphere was assessed by calculating irradiances (200-2000 nm, 15° solar zenith angle, local noon) using a radiative transfer model that accounted for absorption and scattering by the major and minor atmospheric constituents. Comparisons to Earth's surface (46 W m-2, 280-400 nm) suggest that Venus' middle and lower clouds receive ∼87% less normalized UV flux (6-7 W m-2) across 200-400 nm, yet similar normalized photon flux densities (∼4400-6200 μmol m-2 s-1) across 350-1200 nm. Further, Venus' signature phototrophic windows and subwindows overlap with the absorption profiles of several photosynthetic pigments, especially bacteriochlorophyll b from intact cells and phycocyanin. Therefore, Venus' light, with limited UV flux in the middle and lower clouds, is likely quite favorable for phototrophy. We additionally present interpretations to refractive index and radio occultation measures for Venus' aerosols that suggest the presence of lower sulfuric abundances and/or neutralized forms of sulfuric acid, such as ammonium bisulfate. Under these considerations, the aerosols in Venus' middle clouds could harbor water activities (≥0.6) and buffered acidities (Hammett acidity factor, H0 -0.1 to -1.5) that lie within the limits of acidic cultivation (≥H0 -0.4) and are tantalizingly close to the limits of oxygenic photosynthesis (≥H0 0.1). Together, these photophysical and chemical considerations support a potential for phototrophy in Venus' clouds.
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Affiliation(s)
- Rakesh Mogul
- Chemistry & Biochemistry Department, California State Polytechnic University, Pomona, California, USA
| | - Sanjay S Limaye
- Space Science and Engineering Center, University of Wisconsin, Madison, Wisconsin, USA
| | - Yeon Joo Lee
- Zentrum für Astronomie und Astrophysik, Technische Universität Berlin, Berlin, Germany
| | - Michael Pasillas
- Chemistry & Biochemistry Department, California State Polytechnic University, Pomona, California, USA
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Brossier J, Gilmore MS. Variations in the radiophysical properties of tesserae and mountain belts on Venus: Classification and mineralogical trends. ICARUS 2021; 355:114161. [PMID: 33688099 PMCID: PMC7939048 DOI: 10.1016/j.icarus.2020.114161] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Numerous studies show that major Venus highlands display anomalously high radar reflectivity and low radar emissivity relative to the planetary average. This is thought to be the result of the formation of minerals having high dielectric constants via weathering reactions occurring between the surface and the deep atmosphere in these elevated terrains, where temperatures are lower. These reactions are a function of rock composition, atmospheric composition, and degree of weathering, or age. Here, we examine the Magellan radar emissivity, altimetry and backscatter data for all mapped tesserae and mountain belts on Venus. We characterize and classify each contiguous highland according to its pattern of the variation of radar emissivity with increasing altitude. The highlands can be assigned to 7 distinct patterns of emissivity that correspond to at least 2 discrete types of mineralogy based on the altitude (and temperature) of the emissivity changes from the global average (excursions). The majority of the emissivity changes occur at altitudes above 6053 km (temperature below 726 K). The emissivity signature of the major tesserae of Aphrodite Terra, Beta Regio and Phoebe Regio are consistent with the presence of ferroelectric minerals in their rocks (Curie temperatures of ~700-720 K). Fortuna tesserae and the mountains belts (Maxwell, Freyja, Akna and Danu montes) in Ishtar Terra are consistent with the presence of semiconductor minerals. Some tesserae in Ishtar Terra (Clotho, Itzpapatotl and Jyestha tesserae) lie at altitudes over 6055 but lack the emissivity excursions seen in Fortuna tesserae and the mountains at same altitudes and thus may represent a third type of tessera composition. Finally, the spatial distribution of radar emissivity classes correlates to different geologic settings which may reflect differences in the mantle dynamics. Alternatively, this variability could be ascribed to changes in the atmospheric conditions.
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Affiliation(s)
- Jeremy Brossier
- Department of Earth and Environmental Sciences, Planetary Sciences Group, Wesleyan University, 265 Church St., Middletown, CT 06459, USA
| | - Martha S. Gilmore
- Department of Earth and Environmental Sciences, Planetary Sciences Group, Wesleyan University, 265 Church St., Middletown, CT 06459, USA
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Brossier J, Gilmore M, Toner K. Low radar emissivity signatures on Venus volcanoes and coronae: New insights on relative composition and age. ICARUS 2020; 343:113693. [PMID: 33678821 PMCID: PMC7934947 DOI: 10.1016/j.icarus.2020.113693] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Multiple studies reveal that most of Venus highlands exhibit anomalously high radar reflectivity and low radar emissivity relative to the lowlands. This phenomenon is thought to be the result of atmosphere-surface interactions in the highlands, due to lower temperatures. These reactions are a function of rock composition, atmospheric composition, and degree of weathering. We examine the Magellan radar emissivity, altimetry and SAR data for all major volcanoes and coronae on Venus. We characterize and classify edifices according to the pattern of the variation of radar emissivity with altitude. The volcanic highlands can be classified into 7 distinct patterns of emissivity that correspond to at least 3 discrete types of mineralogy based on the altitude (temperature) of the emissivity anomalies. The majority of emissivity anomalies support the hypothesis of a weathering phenomenon at high altitude (>6053 km), but we also find strong emissivity anomalies at lower altitudes that correspond spatially to individual lava flows, indicating variations in mineralogy within an evolving volcanic system. The emissivity signature of tallest volcanoes on Venus are consistent with the presence of ferroelectric minerals in their rocks, while volcanic edifices in western Ishtar Terra and eastern Aphrodite Terra are consistent with the presence of semiconductor minerals. Sapas Mons and Pavlova Corona are also consistent with ferroelectrics, but at a different Curie temperature than the other volcanoes in Atla Regio. The spatial distribution of radar emissivity classes correlates to different geologic settings indicating that different mantle source regions (deep/shallow plumes, and possible convergence zones) may contribute to differences in mineralogy for the studied edifices. Finally, we show that the emissivity signatures of Idunn, Maat and other volcanic edifices are consistent with relatively fresh and unweathered rocks, indicating recent or possibly current volcanism on Venus.
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Platz T, Byrne PK, Massironi M, Hiesinger H. Volcanism and tectonism across the inner solar system: an overview. ACTA ACUST UNITED AC 2014. [DOI: 10.1144/sp401.22] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
AbstractVolcanism and tectonism are the dominant endogenic means by which planetary surfaces change. This book, in general, and this overview, in particular, aim to encompass the broad range in character of volcanism, tectonism, faulting and associated interactions observed on planetary bodies across the inner solar system – a region that includes Mercury, Venus, Earth, the Moon, Mars and asteroids. The diversity and breadth of landforms produced by volcanic and tectonic processes are enormous, and vary across the inventory of inner solar system bodies. As a result, the selection of prevailing landforms and their underlying formational processes that are described and highlighted in this review are but a primer to the expansive field of planetary volcanism and tectonism. In addition to this extended introductory contribution, this Special Publication features 21 dedicated research articles about volcanic and tectonic processes manifest across the inner solar system. Those articles are summarized at the end of this review.
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Affiliation(s)
- T. Platz
- Planetary Science Institute, 1700 East Fort Lowell Road, Tucson, AZ 85719-2395, USA
- Freie Universität Berlin, Institute of Geological Sciences, Planetary Sciences & Remote Sensing, Malteserstrasse 74-100, 12249 Berlin, Germany
| | - P. K. Byrne
- Lunar and Planetary Institute, Universities Space Research Association, 3600 Bay Area Boulevard, Houston, TX 77058, USA
- Department of Terrestrial Magnetism, Carnegie Institution of Washington, 5241 Broad Branch Road NW, Washington, DC 20015-1305, USA
| | - M. Massironi
- Dipartimento di Geoscienze, Universita' degli Studi di Padova, via G. Gradenigo 6, 35131 Padova, Italy
| | - H. Hiesinger
- Institut für Planetologie, Westfälische Wilhelms-Universität Münster, Wilhelm-Klemm-Strasse 10, 48149 Münster, Germany
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Harris LB, Bédard JH. Interactions between continent-like ‘drift’, rifting and mantle flow on Venus: gravity interpretations and Earth analogues. ACTA ACUST UNITED AC 2014. [DOI: 10.1144/sp401.9] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
AbstractRegional shear zones are interpreted from Bouguer gravity data over northern polar to low southern latitudes of Venus. Offset and deflection of horizontal gravity gradient edges (‘worms’) and lineaments interpreted from displacement of Bouguer anomalies portray crustal structures, the geometry of which resembles both regional transcurrent shear zones bounding or cross-cutting cratons and fracture zones in oceanic crust on Earth. High Bouguer anomalies and thinned crust comparable to the Mid-Continent Rift in North America suggest underplating of denser, mantle-derived mafic material beneath extended crust in Sedna and Guinevere planitia on Venus. These rifts are partitioned by transfer faults and flank a zone of mantle upwelling (Eistla Regio) between colinear hot, upwelling mantle plumes. Data support the northward drift and indentation of Lakshmi Planum in western Ishtar Terra and >1000 km of transcurrent displacement between Ovda and Thetis regiones. Large displacements of areas of continent-like crust on Venus are interpreted to result from mantle tractions and pressure acting against their deep lithospheric mantle ‘keels’ commensurate with extension in adjacent rifts. Displacements of Lakshmi Planum and Ovda and Thetis regiones on Venus, a planet without plate tectonics, cannot be attributed to plate boundary forces (i.e. ridge push and slab pull). Results therefore suggest that a similar, subduction-free geodynamic model may explain deformation features in Archaean greenstone terrains on Earth. Continent-like ‘drift’ on Venus also resembles models for the late Cenozoic–Recent Earth, where westward translation of the Americas and northward displacement of India are interpreted as being driven by mantle flow tractions on the keels of their Precambrian cratons.Supplementary material:Bouguer gravity and topographic images over a segment of the Mid-Atlantic ridge and Ross Island and surrounds in Antarctica, principal horizontal stress trajectories about mantle plumes on Earth, map and interactive 3D representations of cratonic keels beneath North America from seismic tomography, and a centrifuge simulation for comparison with Venus in support of our tectonic model are available at http://www.geolsoc.org.uk/SUP18736.
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Affiliation(s)
- Lyal B. Harris
- Institut national de la recherche scientifique, Centre – Eau Terre Environnement (INRS-ETE), 490 de la Couronne, Québec, Canada QC G1K 9A9
| | - Jean H. Bédard
- Geological Survey of Canada, 490 de la Couronne, Québec, Canada QC G1K 9A9
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Interior and Surface Dynamics of Terrestrial Bodies and their Implications for the Habitability. HABITABILITY OF OTHER PLANETS AND SATELLITES 2013. [DOI: 10.1007/978-94-007-6546-7_12] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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10
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Schulze-Makuch D, Méndez A, Fairén AG, von Paris P, Turse C, Boyer G, Davila AF, António MRDS, Catling D, Irwin LN. A two-tiered approach to assessing the habitability of exoplanets. ASTROBIOLOGY 2011; 11:1041-1052. [PMID: 22017274 DOI: 10.1089/ast.2010.0592] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
In the next few years, the number of catalogued exoplanets will be counted in the thousands. This will vastly expand the number of potentially habitable worlds and lead to a systematic assessment of their astrobiological potential. Here, we suggest a two-tiered classification scheme of exoplanet habitability. The first tier consists of an Earth Similarity Index (ESI), which allows worlds to be screened with regard to their similarity to Earth, the only known inhabited planet at this time. The ESI is based on data available or potentially available for most exoplanets such as mass, radius, and temperature. For the second tier of the classification scheme we propose a Planetary Habitability Index (PHI) based on the presence of a stable substrate, available energy, appropriate chemistry, and the potential for holding a liquid solvent. The PHI has been designed to minimize the biased search for life as we know it and to take into account life that might exist under more exotic conditions. As such, the PHI requires more detailed knowledge than is available for any exoplanet at this time. However, future missions such as the Terrestrial Planet Finder will collect this information and advance the PHI. Both indices are formulated in a way that enables their values to be updated as technology and our knowledge about habitable planets, moons, and life advances. Applying the proposed metrics to bodies within our Solar System for comparison reveals two planets in the Gliese 581 system, GJ 581 c and d, with an ESI comparable to that of Mars and a PHI between that of Europa and Enceladus.
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Affiliation(s)
- Dirk Schulze-Makuch
- School of Earth and Environmental Sciences, Washington State University, Pullman, Washington, USA.
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Smrekar SE, Stofan ER, Mueller N, Treiman A, Elkins-Tanton L, Helbert J, Piccioni G, Drossart P. Recent hotspot volcanism on Venus from VIRTIS emissivity data. Science 2010; 328:605-8. [PMID: 20378775 DOI: 10.1126/science.1186785] [Citation(s) in RCA: 190] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
The questions of whether Venus is geologically active and how the planet has resurfaced over the past billion years have major implications for interior dynamics and climate change. Nine "hotspots"--areas analogous to Hawaii, with volcanism, broad topographic rises, and large positive gravity anomalies suggesting mantle plumes at depth--have been identified as possibly active. This study used variations in the thermal emissivity of the surface observed by the Visible and Infrared Thermal Imaging Spectrometer on the European Space Agency's Venus Express spacecraft to identify compositional differences in lava flows at three hotspots. The anomalies are interpreted as a lack of surface weathering. We estimate the flows to be younger than 2.5 million years and probably much younger, about 250,000 years or less, indicating that Venus is actively resurfacing.
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Affiliation(s)
- Suzanne E Smrekar
- Jet Propulsion Laboratory, Mail Stop 183-501, 4800 Oak Grove Drive, Pasadena, CA 91109, USA.
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Erard S, Drossart P, Piccioni G. Multivariate analysis of Visible and Infrared Thermal Imaging Spectrometer (VIRTIS) Venus Express nightside and limb observations. ACTA ACUST UNITED AC 2009. [DOI: 10.1029/2008je003116] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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