SwRI and JPL study reveals liquid brine flows on airless worlds

Written by Copernical Team Wednesday, 23 October 2024 17:24

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Los Angeles CA (SPX) Oct 22, 2024

A collaborative effort between Southwest Research Institute (SwRI) and NASA's Jet Propulsion Laboratory (JPL) seeks to explain mysterious surface features observed on airless celestial bodies, such as the asteroids Vesta and Ceres, and Jupiter's moon Europa. These bodies, recently explored by NASA's Dawn mission and soon by the Europa Clipper mission, exhibit flow patterns that may result from l

SwRI and JPL study reveals liquid brine flows on airless worlds
by Clarence Oxford
Los Angeles CA (SPX) Oct 22, 2024

A collaborative effort between Southwest Research Institute (SwRI) and NASA's Jet Propulsion Laboratory (JPL) seeks to explain mysterious surface features observed on airless celestial bodies, such as the asteroids Vesta and Ceres, and Jupiter's moon Europa. These bodies, recently explored by NASA's Dawn mission and soon by the Europa Clipper mission, exhibit flow patterns that may result from liquid brines formed during meteoroid impacts.

A new study, published in *The Planetary Science Journal*, led by Dr. Michael J. Poston of SwRI, explores how the heat and pressure from an impact can melt subsurface ice on these airless bodies, creating short-lived liquid brines. These brines may flow long enough to form unique features, such as curved gullies and fan-shaped debris patterns, on crater walls.

"We wanted to investigate our previously proposed idea that ice underneath the surface of an airless world could be excavated and melted by an impact and then flow along the walls of the impact crater to form distinct surface features," said Dr. Jennifer Scully (JPL), project PI.

The team simulated the conditions experienced by ice on Vesta following a meteoroid impact. Using a test chamber at JPL, they rapidly decreased pressure over liquid samples to mimic the drop in pressure that occurs as the temporary atmosphere created by the impact dissipates. This rapid pressure change caused liquids to expand and eject material dramatically.

"Through our simulated impacts, we found that the pure water froze too quickly in a vacuum to effect meaningful change, but salt and water mixtures, or brines, stayed liquid and flowing for a minimum of one hour," said Poston. "This is sufficient for the brine to destabilize slopes on crater walls on rocky bodies, cause erosion and landslides, and potentially form other unique geological features found on icy moons."

These findings may help explain features on distant bodies, such as Europa's smooth plains, the distinct "spider" feature in its Manannan crater, and fan-shaped debris deposits on Mars. The research could also support the theory of subsurface water existing in seemingly inhospitable regions of the solar system.

"If the findings are consistent across these dry and airless or thin-atmosphere bodies, it demonstrates that water existed on these worlds in the recent past, indicating water might still be expelled from impacts," added Poston. "There may still be water out there to be found."

The study was funded by NASA's Discovery Data Analysis Program and is part of an ongoing project led by the Jet Propulsion Laboratory at the California Institute of Technology.