MSGID: 1:317/3 627201db   
   PID: hpt/lnx 1.9.0-cur 2019-01-08   
   TID: hpt/lnx 1.9.0-cur 2019-01-08   
    Experiments measure freezing point of extraterrestrial oceans to aid   
   search for life    
      
     Date:   
         May 3, 2022   
     Source:   
         University of Washington   
     Summary:   
         A planetary scientist worked with engineers to measure the physical   
         limits for a liquid when salty water is at very high pressure. The   
         results suggest where to look for extraterrestrial life in the ice-   
         covered oceans of Jupiter's moon Europa and Saturn's moon Titan.   
      
      
      
   FULL STORY   
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   Researchers from the University of Washington and the University   
   of California, Berkeley have conducted experiments that measured the   
   physical limits for the existence of liquid water in icy extraterrestrial   
   worlds. This blend of geoscience and engineering was done to aid in the   
   search for extraterrestrial life and the upcoming robotic exploration   
   of oceans on moons of other planets.   
      
      
   ==========================================================================   
   The results were recently published in Cell Reports Physical Sciences.   
      
   "The more a liquid is stable, the more promising it is for habitability,"   
   said co-corresponding author Baptiste Journaux, an acting assistant   
   professor of Earth and space sciences at the UW. "Our results show that   
   the cold, salty, high-pressure liquids found in the deep ocean of other   
   planets' moons can remain liquid to much cooler temperature than they   
   would at lower pressures.   
      
   This extends the range of possible habitats on icy moons, and will   
   allow us to pinpoint where we should look for biosignatures, or signs   
   of life."  Jupiter and Saturn's icy moons -- including Europa, Ganymede   
   and Titan -- are leading candidates within our solar system for hosting   
   extraterrestrial life.   
      
   These ice-encrusted moons are thought to harbor enormous liquid oceans,   
   up to several dozen times the volume of oceans on Earth.   
      
   "Despite its designation as the 'blue marble,' Earth is remarkably dry   
   when compared to these worlds," Journaux said.   
      
   The oceans on these moons may contain various types of salts and are   
   expected to range from about 100 miles deep, on Europa, to more than   
   400 miles deep, on Titan.   
      
      
      
   ==========================================================================   
   "We know that water supports life, but the major part of the oceans   
   on these moons are likely below zero degrees Celsius and at pressures   
   higher than anything experienced on Earth," Journaux said. "We needed   
   to know how cold an ocean can get before entirely freezing, including   
   in its deepest abyss."  The study focused on eutectics, or the lowest   
   temperature that a salty solution can remain liquid before entirely   
   freezing. Salt and water are one example - - salty water remains liquid   
   below the freezing temperature of pure water, one of the reasons people   
   sprinkle salt on roads in winter to avoid the formation of ice.   
      
   The experiments used UC Berkeley equipment originally designed for the   
   future cryopreservation of organs for medical applications and for food   
   storage. For this research, however, the authors used it to simulate   
   the conditions thought to exist on other planets' moons.   
      
   Journaux, a planetary scientist and expert on the physics of water and   
   minerals, worked with UC Berkeley engineers to test solutions of five   
   different salts at pressures up to 3,000 times atmospheric pressure,   
   or 300 megapascals - - about three times the pressure in Earth's deepest   
   ocean trench.   
      
   "Knowing the lowest temperature possible for salty water to remain a   
   liquid at high pressures is integral to understanding how extraterrestrial   
   life could exist and thrive in the deep oceans of these icy ocean worlds,"   
   said co- corresponding author Matthew Powell-Palm, who did the work as   
   a postdoctoral researcher at UC Berkeley, also co-founder and CEO of   
   the cryopreservation company BioChoric, Inc.   
      
   Journaux recently started working with NASA's Dragonfly mission team,   
   which will send a rotorcraft in 2027 to Saturn's largest moon, Titan. NASA   
   also is leading the Europa Clipper mission in 2024 to explore Europa, one   
   of the many moons orbiting Jupiter. Meanwhile, the European Space Agency   
   in 2023 will send its JUICE spacecraft, or Jupiter Icy Moons Explorer, to   
   explore three of Jupiter's largest moons: Ganymede, Callisto and Europa.   
      
   "The new data obtained from this study may help further researchers'   
   understanding of the complex geological processes observed in these icy   
   ocean worlds," Journaux said.   
      
   Other authors are Boris Rubinsky, Brooke Chang, Anthony Consiglio,   
   Drew Lilley and Ravi Prasher, all at UC Berkeley. The study was funded   
   by the National Science Foundation and NASA.   
      
      
   ==========================================================================   
   Story Source: Materials provided by University_of_Washington. Original   
   written by Hannah Hickey. Note: Content may be edited for style and   
   length.   
      
      
   ==========================================================================   
   Related Multimedia:   
       * Europa   
   ==========================================================================   
   Journal Reference:   
      1. Brooke Chang, Anthony N. Consiglio, Drew Lilley, Ravi Prasher, Boris   
         Rubinsky, Baptiste Journaux, Matthew J. Powell-Palm. On the   
         pressure dependence of salty aqueous eutectics. Cell Reports   
         Physical Science, 2022; 100856 DOI: 10.1016/j.xcrp.2022.100856   
   ==========================================================================   
      
   Link to news story:   
   https://www.sciencedaily.com/releases/2022/05/220503190146.htm   
      
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