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   PID: hpt/lnx 1.9.0-cur 2019-01-08   
   TID: hpt/lnx 1.9.0-cur 2019-01-08   
    Jupiter's moon Europa may have had a slow evolution    
      
     Date:   
         June 17, 2023   
     Source:   
         Arizona State University   
     Summary:   
         Europa may have a metamorphic origin for the ocean. While some   
         scientists speculated this, a research team shows that if Europa   
         indeed formed from hydrated rocks (i.e., rocks have hydrogen and   
         oxygen), then enough of Europa's interior should get hot enough to   
         release water directly from the hydrated rocks to form the ocean   
         and ice shell.   
      
      
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   FULL STORY   
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   Jupiter's moon, Europa, is slightly smaller than Earth's Moon and is   
   one of the most promising places to search for alien life.   
      
   Amid the Jovian system, Europa is of particular interest to scientists   
   because of the strong evidence for nutrients, water and energy to   
   potentially provide a habitable environment for some form of life beyond   
   Earth. In addition, Europa is believed to be made up into four layers   
   (from surface to center): an ice shell, salt water ocean, rocky mantle,   
   and metallic core.   
      
   Like Earth, Europa's ocean touches the rocky seafloor, which may allow   
   for rock-water chemistry favorable for life. Some scientists also believe   
   that the seafloor may host volcanoes, which can provide more energy and   
   nutrients for a potential biosphere.   
      
   ASU scientists Kevin Trinh, Carver Bierson and Joe O'Rourke of the School   
   of Earth and Space Exploration investigated the consequences of Europa   
   forming with low initial temperatures, using computer code that Trinh   
   wrote. Their findings have been recently published in Science Advances.   
      
   Hydrated rocks may be a key ingredient Europa may have a metamorphic   
   origin for the ocean. While some scientists speculated this, Trinh and   
   his team show that if Europa indeed formed from hydrated rocks (i.e.,   
   rocks have hydrogen and oxygen), then enough of Europa's interior should   
   get hot enough to release water directly from the hydrated rocks to form   
   the ocean and ice shell.   
      
   "The origin of Europa's ocean is important because the moon's potential to   
   support life ultimately depends on the chemical ingredients and physical   
   conditions during the ocean formation process," said Kevin Trinh,   
   graduate associate at ASU's School Of Earth and Space Exploration.   
      
   Metallic core formation requires high temperatures Many scientists   
   studying this icy moon assumed that Europa formed with a metallic core   
   during or shortly after accretion. This ASU study contradicts that   
   prediction, instead arguing that Europa may not have started forming its   
   metallic core until billions of years after accretion (if it happened   
   at all).   
      
   "For most worlds in the solar system we tend to think of their internal   
   structure as being set shortly after they finish forming. This work   
   is very exciting because it reframes Europa as a world whose interior   
   has been slowly evolving over its whole lifetime. This opens doors for   
   future research to understand how these changes might be observed in   
   the Europa we see today," said Carver Bierson, postdoctoral research   
   scholar at ASU's School Of Earth and Space Exploration.   
      
   The existence of a metallic core is deeply tied to Europa's internal heat,   
   which may also be used to drive seafloor volcanism and contribute to a   
   habitable seafloor environment. However, it is unclear whether Europa   
   generated enough heat to form such a core. Trinh's code calculates how   
   heat is generated and distributed throughout a moon, which uses the same   
   governing equations that many geodynamicists used for decades. The team's   
   novel result, however, comes from challenging the assumptions common to   
   Europa modeling: A small moon like Europa could form as a cold mixture   
   of ice, rock, and metal.   
      
   However, all of these processes require a hot interior. A small moon   
   like Europa (~1% of Earth's mass) may not have enough energy to trigger   
   or sustain Earth-like processes -- metallic core formation, seafloor   
   volcanism, and ongoing rock-water geochemistry -- which implies that   
   Europa's habitable potential is uncertain. The exact time at which Europa   
   formed determines how much heat is available from the radioactive decay   
   of a short-lived isotope of aluminum. Tidal heating (from gravitational   
   interactions with Jupiter and other moons) also governs how quickly   
   Europa's interior separates into distinct layers.   
      
   Europa's seafloor may be cool, hydrated, and experience limited (if   
   any) seafloor volcanism This study implies that there may be limited   
   hydrothermal activity and seafloor volcanism at Europa, which may hinder   
   habitability. However, confident predictions require more data.   
      
   "Europa is not just a wet, baby Earth. It is its own special world,   
   full of mysteries to unravel," said Joseph O'Rourke, Assistant Professor   
   at ASU's School of Earth and Space Exploration. In October 2024, NASA   
   plans to launch a spacecraft called Europa Clipper, which should arrive   
   at Europa in April 2030.   
      
   With the recent work by Trinh, Bierson and O'Rourke, scientists will   
   be better equipped to interpret incoming data from Europa Clipper,   
   whose main objective is to evaluate Jupiter's icy moon Europa for the   
   potential conditions to host life.   
      
       * RELATED_TOPICS   
             o Space_&_Time   
                   # Jupiter # Moon # Solar_System # Astronomy #   
                   Space_Exploration # Asteroids,_Comets_and_Meteors #   
                   NASA # Pluto   
       * RELATED_TERMS   
             o Mars_Exploration_Rover o Gas_giant o   
             Planetary_nebula o Nuclear_fusion o Hydrogen o   
             Cosmic_microwave_background_radiation o Phoenix_(spacecraft)   
             o Planetary_habitability   
      
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   Story Source: Materials provided by Arizona_State_University. Note:   
   Content may be edited for style and length.   
      
      
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   Journal Reference:   
      1. Kevin T. Trinh, Carver J. Bierson, Joseph G. O'Rourke. Slow   
      evolution of   
         Europa's interior: metamorphic ocean origin, delayed metallic core   
         formation, and limited seafloor volcanism. Science Advances, 2023;   
         9 (24) DOI: 10.1126/sciadv.adf3955   
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   Link to news story:   
   https://www.sciencedaily.com/releases/2023/06/230617004432.htm   
      
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