Jupiter's moon may have balance for life

Wednesday, May 18, 2016 - 10:34 StudyHall.Rocks

Europa could have balance of chemical energy necessary for life.

Image: NASA.

A generation ago, Jupiter was a mere curiosity, a stunning gas giant looming in distant space. But now, in one of a series of revelations about the planet, researchers are probing the habitability of its moon Europa.

    In a newly published study, NASA scientists conclude that the ocean of Europa could have the balance of chemical energy necessary for life, even if the moon lacks volcanic hydrothermal activity, according to a space agency news release.
    NASA scientists have focused on Europa as a promising place to search for signs of life. A planned mission will attempt to survey the moon.
    But scientists are already studying whether Europa has the materials and chemical energy that could support biology. Research released May 17 in Geophysical Research Letters compared “Europa's potential for producing hydrogen and oxygen with that of Earth, through processes that do not directly involve volcanism," the NASA news release explained.
   On Earth, hydrothermal vents release hot and mineral-rich fluids from the seafloor. (See: The Smithsonian Museum of Natural History website.)
     The balance of hydrogen and oxygen is a key indicator of the energy available for life, the news release added. On both worlds, the study found oxygen production is about 10 times higher than hydrogen production.
    Scientists at NASA's Jet Propulsion Laboratory in Pasadena, California, examined how much hydrogen “could potentially be produced in Europa's ocean as seawater reacts with rock in a process called serpentinization,” the news release said. The space agency defines serpentinization as a process in which “water percolates into spaces between mineral grains and reacts with the rock to form new minerals, releasing hydrogen.”
     The study, led by Steve Vance, a planetary scientist at NASA, mentions scientific interest in icy worlds, including Jupiter’s moons Europa, Callisto and Ganymede, Saturn's moons Enceladus and Titan, and probably Neptune's moon Triton.
    “Today, each of these worlds may contain the ingredients for life, the fluxes of chemical energy, water and raw materials that make up cellular material and drive biogeochemistry,” the paper says.
     The authors point out that “pressures and temperatures common to the water-rock interfaces in known and putative ocean-bearing icy worlds, past and present, are outside the ‘terrestrial planet habitable zone’ range in which life grows on Earth. High hydrostatic pressures … and depression of fluid freezing points by compounds such as ammonia must be considered when addressing life's adaptability. In Europa and Enceladus, Earth-like sea floor pressures … and modest temperature conditions make them prime candidates in the search for extant life.”
     Read the paper on the Geophysical Research Letters website.

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