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https://www.readbyqxmd.com/read/28742370/a-community-grows-around-the-geysering-world-of-enceladus
#1
Carolyn C Porco
The discovery by NASA's Cassini mission at Saturn in 2005 of a large plume of material erupting from the south polar terrain of Enceladus, sourced within a subsurface ocean of salty liquid water laced with organic compounds, has brought together scientists from a diverse range of disciplines over the last decade to evaluate this small moon's potential for extraterrestrial life. The collection of papers published today in Astrobiology, as the mission draws to a close, is the outcome of our most recent meeting at UC Berkeley in June 2016...
July 25, 2017: Astrobiology
https://www.readbyqxmd.com/read/28731819/the-close-up-imager-onboard-the-esa-exomars-rover-objectives-description-operations-and-science-validation-activities
#2
Jean-Luc Josset, Frances Westall, Beda A Hofmann, John Spray, Charles Cockell, Stephan Kempe, Andrew D Griffiths, Maria Cristina De Sanctis, Luigi Colangeli, Detlef Koschny, Karl Föllmi, Eric Verrecchia, Larryn Diamond, Marie Josset, Emmanuelle J Javaux, Francesca Esposito, Matthew Gunn, Audrey L Souchon-Leitner, Tomaso R R Bontognali, Oleg Korablev, Suren Erkman, Gerhard Paar, Stephan Ulamec, Frédéric Foucher, Philippe Martin, Antoine Verhaeghe, Mitko Tanevski, Jorge L Vago
The Close-Up Imager (CLUPI) onboard the ESA ExoMars Rover is a powerful high-resolution color camera specifically designed for close-up observations. Its accommodation on the movable drill allows multiple positioning. The science objectives of the instrument are geological characterization of rocks in terms of texture, structure, and color and the search for potential morphological biosignatures. We present the CLUPI science objectives, performance, and technical description, followed by a description of the instrument's planned operations strategy during the mission on Mars...
June 2017: Astrobiology
https://www.readbyqxmd.com/read/28731818/the-adron-rm-instrument-onboard-the-exomars-rover
#3
I G Mitrofanov, M L Litvak, S Y Nikiforov, I Jun, Y I Bobrovnitsky, D V Golovin, A S Grebennikov, F S Fedosov, A S Kozyrev, D I Lisov, A V Malakhov, M I Mokrousov, A B Sanin, V N Shvetsov, G N Timoshenko, T M Tomilina, V I Tret'yakov, A A Vostrukhin
This overview presents the physical principles, design, measurement capabilities, and summary of planned operations of the autonomous detector of radiation of neutrons onboard rover at Mars (ADRON-RM) on the surface of Mars. ADRON-RM is a Russian project selected for the joint European Space Agency-Roscosmos ExoMars 2020 landing mission. A compact passive neutron spectrometer, ADRON-RM, was designed to study the abundance and distribution of water and neutron absorption elements (such as Cl, Fe, and others) in the martian subsurface along the path of the ExoMars rover...
June 2017: Astrobiology
https://www.readbyqxmd.com/read/28731817/infrared-spectrometer-for-exomars-a-mast-mounted-instrument-for-the-rover
#4
Oleg I Korablev, Yurii Dobrolensky, Nadezhda Evdokimova, Anna A Fedorova, Ruslan O Kuzmin, Sergei N Mantsevich, Edward A Cloutis, John Carter, Francois Poulet, Jessica Flahaut, Andrew Griffiths, Matthew Gunn, Nicole Schmitz, Javier Martín-Torres, Maria-Paz Zorzano, Daniil S Rodionov, Jorge L Vago, Alexander V Stepanov, Andrei Yu Titov, Nikita A Vyazovetsky, Alexander Yu Trokhimovskiy, Alexander G Sapgir, Yurii K Kalinnikov, Yurii S Ivanov, Alexei A Shapkin, Andrei Yu Ivanov
ISEM (Infrared Spectrometer for ExoMars) is a pencil-beam infrared spectrometer that will measure reflected solar radiation in the near infrared range for context assessment of the surface mineralogy in the vicinity of the ExoMars rover. The instrument will be accommodated on the mast of the rover and will be operated together with the panoramic camera (PanCam), high-resolution camera (HRC). ISEM will study the mineralogical and petrographic composition of the martian surface in the vicinity of the rover, and in combination with the other remote sensing instruments, it will aid in the selection of potential targets for close-up investigations and drilling sites...
June 2017: Astrobiology
https://www.readbyqxmd.com/read/28727932/laboratory-studies-of-methane-and-its-relationship-to-prebiotic-chemistry
#5
Kensei Kobayashi, Wolf D Geppert, Nathalie Carrasco, Nils G Holm, Olivier Mousis, Maria Elisabetta Palumbo, J Hunter Waite, Naoki Watanabe, Lucy M Ziurys
To examine how prebiotic chemical evolution took place on Earth prior to the emergence of life, laboratory experiments have been conducted since the 1950s. Methane has been one of the key molecules in these investigations. In earlier studies, strongly reducing gas mixtures containing methane and ammonia were used to simulate possible reactions in the primitive atmosphere of Earth, producing amino acids and other organic compounds. Since Earth's early atmosphere is now considered to be less reducing, the contribution of extraterrestrial organics to chemical evolution has taken on an important role...
July 20, 2017: Astrobiology
https://www.readbyqxmd.com/read/28723229/the-formation-of-nucleobases-from-the-ultraviolet-photoirradiation-of-purine-in-simple-astrophysical-ice-analogues
#6
Christopher K Materese, Michel Nuevo, Scott A Sandford
Nucleobases are the informational subunits of RNA and DNA and are essential to all known forms of life. The nucleobases can be divided into two groups of molecules: the pyrimidine-based compounds that include uracil, cytosine, and thymine, and the purine-based compounds that include adenine and guanine. Previous work in our laboratory has demonstrated that uracil, cytosine, thymine, and other nonbiological, less common nucleobases can form abiotically from the UV photoirradiation of pyrimidine in simple astrophysical ice analogues containing combinations of H2O, NH3, and CH4...
July 19, 2017: Astrobiology
https://www.readbyqxmd.com/read/28708419/mechanisms-of-the-formation-of-adenine-guanine-and-their-analogues-in-uv-irradiated-mixed-nh3-h2o-molecular-ices-containing-purine
#7
Partha P Bera, Tamar Stein, Martin Head-Gordon, Timothy J Lee
We investigated the formation mechanisms of the nucleobases adenine and guanine and the nucleobase analogues hypoxanthine, xanthine, isoguanine, and 2,6-diaminopurine in a UV-irradiated mixed 10:1 H2O:NH3 ice seeded with precursor purine by using ab initio and density functional theory computations. Our quantum chemical investigations suggest that a multistep reaction mechanism involving purine cation, hydroxyl and amino radicals, together with water and ammonia, explains the experimentally obtained products in an independent study...
July 14, 2017: Astrobiology
https://www.readbyqxmd.com/read/28708412/digital-holographic-microscopy-a-method-for-detection-of-microorganisms-in-plume-samples-from-enceladus-and-other-icy-worlds
#8
Manuel Bedrossian, Chris Lindensmith, Jay L Nadeau
Detection of extant microbial life on Earth and elsewhere in the Solar System requires the ability to identify and enumerate micrometer-scale, essentially featureless cells. On Earth, bacteria are usually enumerated by culture plating or epifluorescence microscopy. Culture plates require long incubation times and can only count culturable strains, and epifluorescence microscopy requires extensive staining and concentration of the sample and instrumentation that is not readily miniaturized for space. Digital holographic microscopy (DHM) represents an alternative technique with no moving parts and higher throughput than traditional microscopy, making it potentially useful in space for detection of extant microorganisms provided that sufficient numbers of cells can be collected...
July 14, 2017: Astrobiology
https://www.readbyqxmd.com/read/28704064/nucleic-acid-extraction-from-synthetic-mars-analog-soils-for-in-situ-life-detection
#9
Angel Mojarro, Gary Ruvkun, Maria T Zuber, Christopher E Carr
Biological informational polymers such as nucleic acids have the potential to provide unambiguous evidence of life beyond Earth. To this end, we are developing an automated in situ life-detection instrument that integrates nucleic acid extraction and nanopore sequencing: the Search for Extra-Terrestrial Genomes (SETG) instrument. Our goal is to isolate and determine the sequence of nucleic acids from extant or preserved life on Mars, if, for example, there is common ancestry to life on Mars and Earth. As is true of metagenomic analysis of terrestrial environmental samples, the SETG instrument must isolate nucleic acids from crude samples and then determine the DNA sequence of the unknown nucleic acids...
July 13, 2017: Astrobiology
https://www.readbyqxmd.com/read/28702783/origins-of-life-research-a-bibliometric-approach
#10
Arsev Umur Aydinoglu, Zehra Taşkın
This study explores the collaborative nature and interdisciplinarity of the origin(s) of life (OoL) research community. Although OoL research is one of the oldest topics in philosophy, religion, and science; to date there has been no review of the field utilizing bibliometric measures. A dataset of 5647 publications that are tagged as OoL, astrobiology, exobiology, and prebiotic chemistry is analyzed. The most prolific authors (Raulin, Ehrenfreund, McKay, Cleaves, Cockell, Lazcano, etc.), most cited scholars and their articles (Miller 1953, Gilbert 1986, Chyba & Sagan 1992, Wȁchtershȁuser 1988, etc...
July 13, 2017: Origins of Life and Evolution of the Biosphere
https://www.readbyqxmd.com/read/28692303/searching-for-biosignatures-in-exoplanetary-impact-ejecta
#11
Gianni Cataldi, Alexis Brandeker, Philippe Thébault, Kelsi Singer, Engy Ahmed, Bernard L de Vries, Anna Neubeck, Göran Olofsson
With the number of confirmed rocky exoplanets increasing steadily, their characterization and the search for exoplanetary biospheres are becoming increasingly urgent issues in astrobiology. To date, most efforts have concentrated on the study of exoplanetary atmospheres. Instead, we aim to investigate the possibility of characterizing an exoplanet (in terms of habitability, geology, presence of life, etc.) by studying material ejected from the surface during an impact event. For a number of impact scenarios, we estimate the escaping mass and assess its subsequent collisional evolution in a circumstellar orbit, assuming a Sun-like host star...
July 10, 2017: Astrobiology
https://www.readbyqxmd.com/read/28682665/can-life-begin-on-enceladus-a-perspective-from-hydrothermal-chemistry
#12
David Deamer, Bruce Damer
Enceladus is a target of future missions designed to search for existing life or its precursors. Recent flybys of Enceladus by the Cassini probe have confirmed the existence of a long-lived global ocean laced with organic compounds and biologically available nitrogen. This immediately suggests the possibility that life could have begun and may still exist on Enceladus. Here we will compare the properties of two proposed sites for the origin of life on Earth-hydrothermal vents on the ocean floor and hydrothermal volcanic fields at the surface-and ask whether similar conditions could have fostered the origin of life on Enceladus...
July 6, 2017: Astrobiology
https://www.readbyqxmd.com/read/28665680/detecting-darwinism-from-molecules-in-the-enceladus-plumes-jupiter-s-moons-and-other-planetary-water-lagoons
#13
Steven A Benner
To the astrobiologist, Enceladus offers easy access to a potential subsurface biosphere via the intermediacy of a plume of water emerging directly into space. A direct question follows: If we were to collect a sample of this plume, what in that sample, through its presence or its absence, would suggest the presence and/or absence of life in this exotic locale? This question is, of course, relevant for life detection in any aqueous lagoon that we might be able to sample. This manuscript reviews physical chemical constraints that must be met by a genetic polymer for it to support Darwinism, a process believed to be required for a chemical system to generate properties that we value in biology...
June 30, 2017: Astrobiology
https://www.readbyqxmd.com/read/28658221/astrobiology-hunting-aliens
#14
Ramin Skibba
No abstract text is available yet for this article.
June 28, 2017: Nature
https://www.readbyqxmd.com/read/28607347/living-microorganisms-change-the-information-shannon-content-of-a-geophysical-system
#15
Fiona H M Tang, Federico Maggi
The detection of microbial colonization in geophysical systems is becoming of interest in various disciplines of Earth and planetary sciences, including microbial ecology, biogeochemistry, geomicrobiology, and astrobiology. Microorganisms are often observed to colonize mineral surfaces, modify the reactivity of minerals either through the attachment of their own biomass or the glueing of mineral particles with their mucilaginous metabolites, and alter both the physical and chemical components of a geophysical system...
June 12, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28593333/survival-and-adaptation-of-the-thermophilic-species-geobacillus-thermantarcticus-in-simulated-spatial-conditions
#16
Paola Di Donato, Ida Romano, Vincenza Mastascusa, Annarita Poli, Pierangelo Orlando, Mariagabriella Pugliese, Barbara Nicolaus
Astrobiology studies the origin and evolution of life on Earth and in the universe. According to the panspermia theory, life on Earth could have emerged from bacterial species transported by meteorites, that were able to adapt and proliferate on our planet. Therefore, the study of extremophiles, i.e. bacterial species able to live in extreme terrestrial environments, can be relevant to Astrobiology studies. In this work we described the ability of the thermophilic species Geobacillus thermantarcticus to survive after exposition to simulated spatial conditions including temperature's variation, desiccation, X-rays and UVC irradiation...
June 8, 2017: Origins of Life and Evolution of the Biosphere
https://www.readbyqxmd.com/read/28541174/enhancing-a-person-enhancing-a-civilization-a-research-program-at-the-intersection-of-bioethics-future-studies-and-astrobiology
#17
Milan M Ćirković
There are manifold intriguing issues located within largely unexplored borderlands of bioethics, future studies (including global risk analysis), and astrobiology. Human enhancement has for quite some time been among the foci of bioethical debates, but the same cannot be said about its global, transgenerational, and even cosmological consequences. In recent years, discussions of posthuman and, in general terms, postbiological civilization(s) have slowly gained a measure of academic respect, in parallel with the renewed interest in the entire field of future studies and the great strides made in understanding of the origin and evolution of life and intelligence in their widest, cosmic context...
July 2017: Cambridge Quarterly of Healthcare Ethics: CQ: the International Journal of Healthcare Ethics Committees
https://www.readbyqxmd.com/read/28537771/atmospheric-constraints-on-the-surface-uv-environment-of-mars-at-3-9%C3%A2-ga-relevant-to-prebiotic-chemistry
#18
Sukrit Ranjan, Robin Wordsworth, Dimitar D Sasselov
Recent findings suggest that Mars may have been a clement environment for the emergence of life and may even have compared favorably to Earth in this regard. These findings have revived interest in the hypothesis that prebiotically important molecules or even nascent life may have formed on Mars and been transferred to Earth. UV light plays a key role in prebiotic chemistry. Characterizing the early martian surface UV environment is key to understanding how Mars compares to Earth as a venue for prebiotic chemistry...
May 24, 2017: Astrobiology
https://www.readbyqxmd.com/read/28520475/kombucha-multimicrobial-community-under-simulated-spaceflight-and-martian-conditions
#19
O Podolich, I Zaets, O Kukharenko, I Orlovska, O Reva, L Khirunenko, M Sosnin, A Haidak, S Shpylova, E Rabbow, M Skoryk, M Kremenskoy, R Demets, N Kozyrovska, J-P de Vera
Kombucha microbial community (KMC) produces a cellulose-based biopolymer of industrial importance and a probiotic beverage. KMC-derived cellulose-based pellicle film is known as a highly adaptive microbial macrocolony-a stratified community of prokaryotes and eukaryotes. In the framework of the multipurpose international astrobiological project "BIOlogy and Mars Experiment (BIOMEX)," which aims to study the vitality of prokaryotic and eukaryotic organisms and the stability of selected biomarkers in low Earth orbit and in a Mars-like environment, a cellulose polymer structural integrity will be assessed as a biomarker and biotechnological nanomaterial...
May 2017: Astrobiology
https://www.readbyqxmd.com/read/28520474/survival-of-deinococcus-geothermalis-in-biofilms-under-desiccation-and-simulated-space-and-martian-conditions
#20
Jan Frösler, Corinna Panitz, Jost Wingender, Hans-Curt Flemming, Petra Rettberg
Biofilm formation represents a successful survival strategy for bacteria. In biofilms, cells are embedded in a matrix of extracellular polymeric substances (EPS). As they are often more stress-tolerant than single cells, biofilm cells might survive the conditions present in space and on Mars. To investigate this topic, the bacterium Deinococcus geothermalis was chosen as a model organism due to its tolerance toward desiccation and radiation. Biofilms cultivated on membranes and, for comparison, planktonically grown cells deposited on membranes were air-dried and exposed to individual stressors that included prolonged desiccation, extreme temperatures, vacuum, simulated martian atmosphere, and UV irradiation, and they were exposed to combinations of stressors that simulate space (desiccation + vacuum + UV) or martian (desiccation + Mars atmosphere + UV) conditions...
May 2017: Astrobiology
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