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  1. A Possible Solution to “Faint Young Sun Paradox” in Primordial Asteroid Impacts


    SwRI scientists created a new model for impact-generated outgassing on the early Earth. A large impact creates a transient high temperature atmosphere. Within a thousand years, the atmosphere condenses, while deep-seated, impact-generated melt spreads across the surface. The model shows how pools of lava could release gases and create a greenhouse effect that warmed the planet.  Image credit: Simone Marchi (SwRI), Benjamin Black (City College of New York)
    SwRI scientists created a new model for impact-generated outgassing on the early Earth. A large impact creates a transient high temperature atmosphere. Within a thousand years, the atmosphere condenses, while deep-seated, impact-generated melt spreads across the surface. The model shows how pools of lava could release gases and create a greenhouse effect that warmed the planet.

    In the first billion years of Earth’s history, the planet was bombarded by primordial asteroids, while a faint Sun provided much less heat. A Southwest Research Institute-led team posits that this tumultuous beginning may have ultimately fostered life on Earth, particularly in terms of sustaining liquid water.

    “The early impacts caused temporary, localized destruction and hostile conditions for life. But at the same time, they had a long-term beneficial effect in stabilizing surface temperatures and delivering key elements for life as we know it,” said Dr. Simone Marchi, a senior research scientist at SwRI’s Planetary Science Directorate in ...

    Source: [Southwest Research Institute]

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  1. Watching ‘Jumping Genes’ in Action


    A bacterial colony showing individual cells undergoing transposable element events, resulting in blue fluorescence. Images are shown at (a) t = 0, (b) t = 40 min, and (c) t = 60 min, with arrows indicating newly occurring events in each image. Image courtesy of T.E. Kuhlman, University of Illinois at Urbana-Champaign, reproduced with permission from Proceedings of the National Academy of Sciences USA. Image credit: None
    A bacterial colony showing individual cells undergoing transposable element events, resulting in blue fluorescence. Images are shown at (a) t = 0, (b) t = 40 min, and (c) t = 60 min, with arrows indicating newly occurring events in each image. Image courtesy of T.E. Kuhlman, University of Illinois at Urbana-Champaign, reproduced with permission from Proceedings of the National Academy of Sciences USA.

    “Jumping genes” are ubiquitous. Every domain of life hosts these sequences of DNA that can “jump” from one position to another along a chromosome; in fact, nearly half the human genome is made up of jumping genes. Depending on their specific excision and insertion points, jumping genes can interrupt or trigger gene expression, driving genetic mutation and contributing to cell diversification. Since their discovery in the 1940s, researchers have been able to study the behavior of these jumping genes, generally known as transposons or transposable elements (TE), primarily through indirect methods that infer individual activity from bulk results. However, such ...

    Source: [University of Illinois at Urbana-Champaign]

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  1. Chiral Molecule Detected in Interstellar Space


    Propylene oxide was detected, primarily with the NSF's Green Bank Telescope, near the center of our Galaxy in Sagittarius (Sgr) B2, a massive star-forming region. Credit: B. Saxton, NRAO/AUI/NSF from data provided by N.E. Kassim, Naval Research Laboratory Image credit:
    Propylene oxide was detected, primarily with the NSF's Green Bank Telescope, near the center of our Galaxy in Sagittarius (Sgr) B2, a massive star-forming region. Credit: B. Saxton, NRAO/AUI/NSF from data provided by N.E. Kassim, Naval Research Laboratory

    A team of scientists using highly sensitive radio telescopes have discovered the first complex organic chiral molecule in interstellar space. The molecule, propylene oxide (CH3CHOCH2), was found near the center of our Galaxy in an enormous star-forming cloud of dust and gas known as Sagittarius B2 (Sgr B2).

    The research was undertaken primarily with the National Science Foundation’s Green Bank Telescope (GBT) in West Virginia as part of the Prebiotic Interstellar Molecular Survey. Additional supporting observations were taken with the Parkes radio telescope in Australia.

    “This is the first molecule detected in interstellar space that has the ...

    Source: [National Radio Astronomy Observatory]

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  1. Postdoctoral Fellowship Opportunity with NASA’s Nexus for Exoplanet System Science (NExSS)


    Image credit: None

    The NASA Postdoctoral Program (NPP) offers U.S. and international scientists the opportunity to conduct important research while contributing to NASA’s scientific goals. Applications are now being accepted for postdoctoral fellows to engage in research with NASA’s Nexus for Exoplanet System Science (NExSS) advisors.

    NExSS is a NASA research coordination network dedicated to the study of planetary habitability. The goals of NExSS are to investigate the diversity of exoplanets and to learn how their history, geology, and climate interact to create the conditions for life (https://nexss.info/). NExSS investigators also strive to put planets into an architectural ...

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  1. Pre-Workshop Activities for Exoplanet Biosignatures Workshop Without Walls


    Image credit: None

    The pre-workshop online activities for the NExSS Exoplanet Biosignatures Workshop Without Walls will commence on June 13! We are pleased to let you know that 3 pairs of meetings will be timed to engage participants across the globe.

    These pre-workshop activities will be community work sessions to review the State of the Science of remotely detectable biosignatures. The results will be summarized at the 3-day in-person workshop in July, where they will facilitate discussions for Advancing the Science and Technology for exoplanet biosignatures.

    State of the Science Review
    The length of each meeting will be 75 minutes.

    Meeting 1: Topic ...

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  1. Joint NASA-NSF Ideas Lab on the Origins of Life


    Image credit: None

    The Astrobiology Program of NASA’s Science Mission Directorate (SMD) is joining with the Directorate for Biological Sciences (BIO) and the Directorate of Geosciences (GEO) of the National Science Foundation to sponsor an “Ideas Lab” activity on the Origins of Life.

    Scientific Background

    Most theories of the origin and early evolution of life focus on one of two different models. “Metabolism first” approaches generally focus on non-biological sources for the reactions of metabolism and rarely discuss in detail how bio-polymers (proteins or poly-nucleotides) arose to catalyze them. “RNA World” models assume that metabolic ribozymes existed but never describe how or ...

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  1. Earth’s ancient atmosphere was half as thick as it is today


    The idea that the young Earth had a thicker atmosphere turns out to be wrong. New research from the University of Washington uses bubbles trapped in 2.7 billion-year-old rocks to show that air at that time exerted, at most, half the pressure of today’s atmosphere. Read the full article from The University of Washington.

    The study, “Earth’s air pressure 2.7 billion years ago constrained to less than half of modern levels,” was published in the journal Nature: Geoscience. The research was supported by the Exobiology and Evolutionary Biology and NASA Astrobiology Institute elements of the ...

    Source: [University of Washington]

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  1. Below the Chemocline in a Meromictic Lake


    Mahoney Lake in British Columbia. Image credit: W. P. Gilhooly III
    Mahoney Lake in British Columbia.

    Metagenomic sequencing has provided new information about understudied populations of microorganisms that inhabit Mahoney Lake in British Columbia at depths where light does not reach. Mahoney Lake is an extreme meromictic system, meaning that the lake contains layers of water that do not mix. There is a great deal of information concerning microorganisms that live in sunlit portions of Mahoney Lake, and similar anoxic systems that contain high levels of sulfate and sulfide in the water column. However, less is known about communities living at depths below the photic zone.

    The new study provides insight into the the types of ...

    Source: [Frontiers in Microbiology]

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  1. Early Career Seminar: Chemical Gardens, Chimneys, and Fuel Cells: Simulating Prebiotic Chemistry in Hydrothermal Vents on Ocean Worlds


    Image credit: None

    On Wednesday, June 1, 2016 at 11AM PDT, Laura Barge, NASA Jet Propulsion Laboratory, will be presenting the next early career seminar, Early Career Seminar: Chemical Gardens, Chimneys, and Fuel Cells: Simulating Prebiotic Chemistry in Hydrothermal Vents on Ocean Worlds.

    Abstract: Planetary water-rock interfaces generate energy in the form of redox, pH, and thermal gradients, particularly in hydrothermal systems where the reducing, heated vent fluid feeds back into the more oxidizing ocean. Alkaline vents produced by serpentinization have been proposed as a possible location for the emergence of life on the early Earth due to various factors, including the mineral ...

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  1. Genetic Studies of a Hyperthermophilic Archaeon


    Lead author, Changyi Zhang, collecting samples in September 2014 at a hot spring in Yellowstone National Park. Image credit: Zhang et a. (2016)/University of Illinois at Urbana-Champaign
    Lead author, Changyi Zhang, collecting samples in September 2014 at a hot spring in Yellowstone National Park.

    Scientists from Carl R. Woese Institute for Genomic Biology have identified a new genetic marker (the apt gene) in a species of archaea named Sulfolobus islandicus. S. islandicus is a hyperthermophilic member of the phylum Crenarchaeota, and can be found in environments like volcanic springs with temperatures up to 91°C. Currently, S. islandicus is rapidly developing as a model for studying archaeal biology as well as linking novel biology to evolutionary ecology using functional population genomics.

    Previously, only one similar genetic marker (the pyrEF gene) was known for Sulfolobus species. However, the majority of Sulfolobus mutants that have been ...

    Source: [Applied and Environmental Microbiology]

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  1. New Insight into Microbial Communities in Anoxic Sediments


    Scanning electron micrographs of anaerobic Fe(II)-oxidizing cultures. From: Schadler et al. (2009) Formation of Cell-Iron-Mineral Aggregates by Phototrophic and Nitrate-Reducing Anaerobic Fe(II)-Oxidizing Bacteria, Geomicrobiology Journal.  Image credit: Reprinted by permission of Taylor & Francis LLC, (http://www.tandfonline.com)
    Scanning electron micrographs of anaerobic Fe(II)-oxidizing cultures. From: Schadler et al. (2009) Formation of Cell-Iron-Mineral Aggregates by Phototrophic and Nitrate-Reducing Anaerobic Fe(II)-Oxidizing Bacteria, Geomicrobiology Journal.

    A new study provides insight into a well-recognized chemolithotrophic pathway that can be used by microorganisms inhabiting anoxic sediments. Researchers used an enrichment culture of chemolithoautotrophic organisms from freshwater sediments (dubbed Culture KS) as a model system to study the pathway: nitrate-dependent ferrous iron [Fe(II)] oxidation (NDFO).

    Previous efforts to isolate the organism responsible for the oxidation of iron [Fe(II)] in Culture KS had proven unsuccessful. In the new study, researchers used metagenomic analysis to better understand the roles of different bacteria in Culture KS. Using this method, they were able to identify the primary Fe(II)-oxidizer ...

    Source: [Applied Environmental Microbiology]

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  1. Workforce Trends in Geosciences Infographic


    The colored rings signify the different sectors where geoscientists work. The wedges, in turn, represent the fields where geoscientists are employed and include different examples of occupations. Where the wedges intersect with the rings indicates that those fields are included in those sectors.
Image credit: Illustrator: Kathleen Cantner. Content: Heather Houlton & Abigail Seadler
 Image credit:
    The colored rings signify the different sectors where geoscientists work. The wedges, in turn, represent the fields where geoscientists are employed and include different examples of occupations. Where the wedges intersect with the rings indicates that those fields are included in those sectors. Image credit: Illustrator: Kathleen Cantner. Content: Heather Houlton & Abigail Seadler

    The American Geosciences Institute (AGI) developed an infographic as a part of their Preparing Our Workforce (POW) Initiative to help students entering the workforce redefine what it means to have a career in geoscience. Having a successful geoscience career is not solely about mastering the technical fields of study. Students must seamlessly integrate their interests and competencies to build a professional portfolio that bolsters their career. Recognizing the importance of emphasizing the transferability of skills across different fields is imperative to students’ employability as geoscientists.

    Read more >

    Source: [American Geosciences Institute ]

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  1. The Universal Structure of Human Lexical Semantics


    A new study explores how properties of organization and cognition in the human brain could be universal. Researchers focused on semantics, or ‘meaning expressed through language,’ and developed an empirical measure of how semantics might reflect cultural, historical, and environmental backgrounds. The results highlight a universal structure underlying the sampled vocabulary across different language groups and largely independent of geography or environment.

    Schematic of a bipartite semantic network constructed through translation (first layer to second layer) and back-translation (second layer to third layer) for MOON and SUN in two American languages: Coast Tsimshian (red) and Lakhota (blue). Image credit: Youn et al. (2016)
    Schematic of a bipartite semantic network constructed through translation (first layer to second layer) and back-translation (second layer to third layer) for MOON and SUN in two American languages: Coast Tsimshian (red) and Lakhota (blue).

    Source: [PNAS]

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  1. Stromatolites, it’s a Matter of Scale


    In situ macro and mesostructure of Barstow Formation tufa. Image credit: Ibarra and Corsetti Image credit:
    In situ macro and mesostructure of Barstow Formation tufa. Image credit: Ibarra and Corsetti

    The processes that govern the formation of stromatolites—structures that may represent macroscopic manifestation of microbial processes and a clear target for astrobiological investigation—occur at various scales (local versus regional), yet determining their relative importance remains a challenge, particularly for ancient deposits and/or if similar deposits are discovered elsewhere in the Solar System.

    A new paper builds upon the traditional multiscale level approach of investigation (micro-, meso-, macro-, mega-) by including a lateral comparative investigational component of fine- to large-scale features to determine the relative significance of local and/or nonlocal controls on stromatolite morphology, and in the ...

    Source: [Astrobiology]

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  1. An Inner Edge for Habitable Planets around Low-Mass Stars


    Our sun has a temperature of about 5800K. For stars cooler than our sun (M dwarfs at 3000-4000K) the habitable zone is closer in. For hotter stars (A dwarfs at 10,000K) the region is much farther out.  Image credit: NASA
    Our sun has a temperature of about 5800K. For stars cooler than our sun (M dwarfs at 3000-4000K) the habitable zone is closer in. For hotter stars (A dwarfs at 10,000K) the region is much farther out.

    Researchers have provided new estimates for the inner edge of the habitable zone for synchronously rotating terrestrial planets around late-K and M-dwarf stars. Using a 3-D Earth-analog global climate model (GCM), the team has shed new light on the relationship between the rotational rates of planets and habitability around these types of stars. The results indicate that rotation rates for planets at the inner edge of the habitable zone become faster and that the inner edge is farther away from the host star than indicated in previous GCM studies.

    The paper, “The inner edge of the habitable zone for synchronously ...

    Source: [Earth and Planetary Astrophysics]

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