Earth Sciences

Oxford University

Podcasts from the department of Earth Sciences.

পর্ব

  1. ২৭/০৪/২০১৭ ·  ভিডিও

    Curiosity’s Search for Ancient Habitable Environments at Gale Crater, Mars

    4th Annual Lobanov-Rostovsky Lecture in Planetary Geology delivered by Professor John Grotzinger, Caltech, USA The Mars Science Laboratory rover, Curiosity, touched down on the surface of Mars on August 5, 2012. Curiosity was built to search and explore for habitable environments and has a lifetime of at least one Mars year (~23 months), and drive capability of at least 20 km. The MSL science payload can assess ancient habitability which requires the detection of former water, as well as a source of energy to fuel microbial metabolism, and key elements such carbon, sulfur, nitrogen, and phosphorous. The search for complex organic molecules is an additional goal and our general approach applies some of the practices that have functioned well in exploration for hydrocarbons on Earth. The selection of the Gale Crater exploration region was based on the recognition that it contained multiple and diverse objectives, ranked with different priorities, and thus increasing the chances of success that one of these might provide the correct combination of environmental factors to define a potentially habitable paleoenvironment. Another important factor in exploration risk reduction included mapping the landing ellipse ahead of landing so that no matter where the rover touched down, our first drive would take us in the direction of a science target deemed to have the greatest value as weighed against longer term objectives, and the risk of mobility failure. Within 8 months of landing we were able to confirm full mission success. This was based on the discovery of fine-grained sedimentary rocks, inferred to represent an ancient lake. These Fe-Mg-rich smectitic mudstones preserve evidence of an aqueous paleoenvironment that would have been suited to support a Martian biosphere founded on chemolithoautotrophy and characterized by neutral pH, low salinity, and variable redox states of both iron and sulfur species. The environment likely had a minimum duration of hundreds to tens of thousands of years. In the past year simple chlorobenzene and chloroalkane molecules were confirmed to exist within the mudstone. These results highlight the biological viability of fluvial-lacustrine environments in the ancient history of Mars and the value of robots in geologic exploration.

    ১ঘঃ ৯মিঃ

  2. ২৭/০৪/২০১৭ ·  ভিডিও

    The Origins and Evolution of Exoplanet Atmospheres and Oceans

    3rd Annual Lobanov-Rostovsky Lecture in Planetary Geology delivered by Professor Raymond T Pierrehumbert. Atmospheres are dynamic entities, formed from the volatile substances that accrete when a planet is formed and later in its history, cooked out in the hot-high pressure interior of the planet, and exchanging with the interior through crustal processes (for planets which have a solid surface) or mixing into the deep interior (for fluid planets). Loss of atmosphere to space is also a major mechanism whereby the chemical composition of entire planets evolve. There is thus no distinct boundary between the disciplines of planetary geology and planetary atmospheres, and the dawning age of exoplanet discovery has made it even more essential to think across the boundaries of the two disciplines. The likely characteristics of known exoplanets greatly expand the range of substances that have to be thought of as atmospheric components, with many things thought of as “rocks and minerals” on Earth being atmospheric or cloud forming substances. There are planets hot enough to have permanent magma oceans which may give rise to rock vapor atmospheres, and others where clouds may be formed of enstatite or even sapphire (or more prosaically, corundum). Some of these atmospheres are supersonic and local; others may be global and subsonic. There is also a host of new problems to be thought about in connection with “gas midgets,” which are mostly fluid but small enough that they need not have a hydrogen dominated composition. In this lecture, I will provide a survey of the emerging field of integrated planetary science, and conclude with some thoughts on how to train the next generation of planetary scientists to deal with the leading-edge problems of the future.

    ৫৭ মিনিট

  3. ২২/০৫/২০১৫ ·  ভিডিও

    The Formation of Terrestrial Planets - the 2nd Lobanov-Rostovsky Lecture in Planetary Geology

    Prof Alessandro Morbidelli of the Observatoire de la Cote d'Azur in Nice gives the 2nd Lobanov-Rostovsky Lecture in Planetary Geology. He talks about the formation of planets in the universe. Morbidelli uses numerical modelling and geochemical and cosmochemical analyses to explain planetary formation within our solar system. He provides a growth history of the Earth, with reference to the specific elements found in the Earth mantle, as well as insight into the composition and timing of moon formation.

    ৫৬ মিনিট

  4. ০৬/১১/২০১৩ ·  ভিডিও

    Building Earth-like Planets: from gas and dust to ocean worlds.

    The first Lobanov-Rostovsky Lecture in Planetary Geology delivered by Professor Linda T. Elkins-Tanton.

    ৫১ মিনিট

  5. ১৬/০৪/২০১৩ ·  ভিডিও

    The Chelyabinsk Meteor

    In this talk Dr Ken Amor talks about the Chelyabinsk meteor, which entered Earths atmosphere over Russia on the 15th of February 2013.

    ১৪ মিনিট

  6. ৩০/০১/২০১৩ ·  ভিডিও

    Large Meteorite Impacts on Earth

    Ken Amor looks at the science of large meteorite impacts on Earth.

    ১২ মিনিট

  7. ০১/০৬/২০১১ ·  ভিডিও

    Ironing The Ocean - exploring the ocean iron and carbon cycles aboard the RRS discovery in the south atlantic

    Gideon Henderson, Professor of Earth Sciences and fellow of University College, gives a talk on his research on iron content in the atlantic ocean and its necessity for life in the ocean.

    ৪৬ মিনিট

  8. ২৫/১০/২০১০ ·  ভিডিও

    Rocking the Cradle...6,000 Years of Geological Impact in Greece

    From the 2010 Alumni Weekend. Phillip England talks about the history of Greece through its many earthquakes and seismic activity over the last 6000 years and shows how these events shaped the ancient world's history.

    ৫৯ মিনিট
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বিষয়ে

Podcasts from the department of Earth Sciences.

তথ্য

  • ক্রিয়েটর
    Oxford University
  • অ্যাকটিভ বছর
    ২০১১ - ২০১৭
  • পর্ব
    ৮
  • রেটিং
    পরিষ্কার করুন
  • কপিরাইট
    © Oxford University
  • ওয়েবসাইট দেখান
    Earth Sciences

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