• Mars Study Yields Clues to Possible Cradle of Life

    From baalke@1:2320/100 to sci.space.news on Thu Oct 19 23:40:36 2017
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    https://www.jpl.nasa.gov/news/news.php?feature=6966

    Mars Study Yields Clues to Possible Cradle of Life
    Jet Propulsion Laboratory
    October 6, 2017

    Fast Facts:

    * A long-gone sea on southern Mars once held nearly 10 times as much water
    as all of North America's Great Lakes combined, a recent report estimates.

    * The report interprets data from NASA's Mars Reconnaissance Orbiter as evidence that hot springs pumped mineral-laden water directly into this ancient Martian sea.

    * Undersea hydrothermal conditions on Mars may have existed about 3.7
    billion years ago; undersea hydrothermal conditions on Earth at about
    that same time are a strong candidate for where and when life on Earth
    began.

    * The report adds an important type of wet ancient Martian environment
    to the diversity indicated by previous findings of evidence for rivers,
    lakes, deltas, seas, groundwater and hot springs.

    The discovery of evidence for ancient sea-floor hydrothermal deposits
    on Mars identifies an area on the planet that may offer clues about the
    origin of life on Earth.

    A recent international report examines observations by NASA's Mars Reconnaissance
    Orbiter (MRO) of massive deposits in a basin on southern Mars. The authors interpret the data as evidence that these deposits were formed by heated
    water from a volcanically active part of the planet's crust entering the bottom of a large sea long ago.

    "Even if we never find evidence that there's been life on Mars, this site
    can tell us about the type of environment where life may have begun on
    Earth," said Paul Niles of NASA's Johnson Space Center, Houston. "Volcanic activity combined with standing water provided conditions that were likely similar to conditions that existed on Earth at about the same time --
    when early life was evolving here."

    Mars today has neither standing water nor volcanic activity. Researchers estimate an age of about 3.7 billion years for the Martian deposits attributed to seafloor hydrothermal activity. Undersea hydrothermal conditions on
    Earth at about that same time are a strong candidate for where and when
    life on Earth began. Earth still has such conditions, where many forms
    of life thrive on chemical energy extracted from rocks, without sunlight.
    But due to Earth's active crust, our planet holds little direct geological evidence preserved from the time when life began. The possibility of undersea hydrothermal activity inside icy moons such as Europa at Jupiter and Enceladus at Saturn feeds interest in them as destinations in the quest to find extraterrestrial life.

    Observations by MRO's Compact Reconnaissance Spectrometer for Mars (CRISM) provided the data for identifying minerals in massive deposits within
    Mars' Eridania basin, which lies in a region with some of the Red Planet's most ancient exposed crust.

    "This site gives us a compelling story for a deep, long-lived sea and
    a deep-sea hydrothermal environment," Niles said. "It is evocative of
    the deep-sea hydrothermal environments on Earth, similar to environments
    where life might be found on other worlds -- life that doesn't need a
    nice atmosphere or temperate surface, but just rocks, heat and water."

    Niles co-authored the recent report in the journal Nature Communications
    with lead author Joseph Michalski, who began the analysis while at the
    Natural History Museum, London, andco-authors at the Planetary Science Institute in Tucson, Arizona, and the Natural History Museum.

    The researchers estimate the ancient Eridania sea held about 50,000 cubic miles (210,000 cubic kilometers) of water. That is as much as all other
    lakes and seas on ancient Mars combined and about nine times more than
    the combined volume of all of North America's Great Lakes. The mix of
    minerals identified from the spectrometer data, including serpentine,
    talc and carbonate, and the shape and texture of the thick bedrock layers,
    led to identifying possible seafloor hydrothermal deposits. The area has
    lava flows that post-date the disappearance of the sea. The researchers
    cite these as evidence that this is an area of Mars' crust with a volcanic susceptibility that also could have produced effects earlier, when the
    sea was present.

    The new work adds to the diversity of types of wet environments for which evidence exists on Mars, including rivers, lakes, deltas, seas, hot springs, groundwater, and volcanic eruptions beneath ice.

    "Ancient, deep-water hydrothermal deposits in Eridania basin represent
    a new category of astrobiological target on Mars," the report states.
    It also says, "Eridania seafloor deposits are not only of interest for
    Mars exploration, they represent a window into early Earth." That is because the earliest evidence of life on Earth comes from seafloor deposits of
    similar origin and age, but the geological record of those early-Earth environments is poorly preserved.

    The Johns Hopkins University Applied Physics Laboratory, Laurel, Maryland, built and operates CRISM, one of six instruments with which MRO has been examining Mars since 2006. NASA's Jet Propulsion Laboratory, a division
    of Caltech in Pasadena, California, manages the project for the NASA Science Mission Directorate in Washington. Lockheed Martin Space Systems of Denver built the orbiter and supports its operations. For more about MRO, visit:

    https://mars.nasa.gov/mro

    News Media Contact
    Guy Webster
    Jet Propulsion Laboratory, Pasadena, Calif.
    818-354-6278
    guy.webster@jpl.nasa.gov

    Jenny Knotts
    Johnson Space Center, Houston
    281-483-5111
    Norma.j.knotts@nasa.gov

    Laurie Cantillo / Dwayne Brown
    NASA Headquarters, Washington
    202-358-1077 / 202-358-1726
    laura.l.cantillo@nasa.gov / dwayne.c.brown@nasa.gov

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