Upside down, underwater snow spotted on Jupiter’s Europa
It moves up instead of falling
On Earth we may know that snow falls from the sky, but on Jupiter’s icy moon, Europa, it appears to be moving in reverse. A new study by the University of Texas reveals that Europa’s icy crust may be composed in some parts of Frazil ice, a collection of loose, randomly oriented millimeter-sized ice crystals.
This kind of ice is also found under glaciers on Earth. Frazil ice holds only a small percentage of the salt found in normal glacier ice, leading scientists to suspect that Europa’s ice may be less salty than previously thought.
When we explore Europa, we care about the salinity and composition of the ocean because it will determine the likelihood of habitability or even what kind of life might already be living there.
According to the latest developments, there are two types of ice in Europe. One is ice that comes from the ice sheet itself at the surface. The other is Frazil ice, which forms in salty seawater and moves to the surface as flakes – following the opposite movement of snow on Earth – where it becomes trapped under the ice sheet.
Europa is one of the most interesting objects in the Solar System for astrobiologists, as it is covered by an ocean 150 km deep and covered with ice 25 km thick on the surface. It is 1/4 the size of Earth, yet because the ocean covers its entire surface, it has twice as much water as Earth. Launching in October 2024, NASA’s Europa Clipper mission will pass by Europa providing valuable information.
While regular ice contains 10% of seawater salt, Frazil ice contains just 0.1%. This affects the structure and strength of Europa’s icy crust, but may also have implications for how well Clipper’s radar will be able to penetrate the ice.
This research opens up new possibilities when thinking about ocean worlds and how they work. It sets the stage for how we can prepare for the ice analysis that the Europa Clipper will provide.
The research was published in Astrobiology
