September 25, 2012
Water On Jupiter Moon Europa Not Always In A Liquid State
Lee Rannals for redOrbit.com - Your Universe Online
Researchers announced at the European Planetary Science Congress in Madrid on Tuesday that the liquid water found on one of Jupiter's moons may not always be in that state.
Europa is believed to be hosting a subsurface ocean of liquid water beneath, but a new study suggests that this water does not stay in this liquid state for longer than a few tens of thousands of years.
Astronomers believe the moon contains a water shell about 62 miles beneath a crust of solid ice. Europa is warmed enough to maintain its liquid state by heat produced as a by-product of gravitational pulling to-and-from Jupiter.
Pockets of liquid water could be found enticingly close to the surface, but the researchers report that this could be short-lived.
“A global water ocean may be present, but relatively deep below the surface — around 25 to 50km. There could be areas of liquid water at much shallower depths, say around 5km, but these would only exist for a few tens of thousands of years before migrating downwards,” said KlÃ¡ra KalousovÃ¡, from the University of Nantes and Charles University in Prague.
KalousovÃ¡ reached the conclusions by mathematically modeling mixtures of liquid water and solid ice under different conditions.
She found that due to density and viscosity differences, liquid water migrates rapidly downwards through partially molten ice, eventually reaching the subsurface ocean.
“As well as helping us to better understand Europa´s water cycle, this research could provide insight into icy moons that are geologically active, such as Enceladus, and worlds that have cycles connecting the interior with a surface," KalousovÃ¡ said.
Image 2 (below): This artist´s cutaway view shows our current understanding of Europa´s interior. Credit: NASA/JPL