How Enceladus' ocean spray becomes chemically diverse ice grains
Saturn's icy moon Enceladus hides a global ocean beneath its frozen surface. From fractures near its south pole, material from this ocean is ejected into space as a plume of water vapor and ice particles. These particles offer scientists a rare opportunity to investigate an extraterrestrial ocean without drilling through kilometers of ice.
The ocean beneath Saturn's moon Enceladus is revealed to be chemically diverse, with ice grains ejected from its subsurface ocean exhibiting strikingly different compositions. An international research team, including scientists from the Earth-Life Science Institute (ELSI) at the Institute of Science Tokyo, found that these ice grains, observed by the Cassini spacecraft's Cosmic Dust Analyzer, are enriched in various salts such as sodium chloride, carbonates, phosphates, and potassium chloride.
The team discovered that the diversity in ice grain composition arises from the varying cooling rates during the freezing process of ocean droplets. When droplets around 200 micrometers across freeze slowly, at approximately 10 K per minute or less, salts become spatially separated, resulting in different chemical compositions in the resulting ice grains.
This finding challenges previous assumptions about the rapid freezing of seawater spray near Enceladus and suggests that droplets may travel more slowly through the subsurface vent system before reaching the surface.
Brief written by urgent.news from Phys.org's own syndicated text. Machine-written — may contain errors; check the original before relying on it.
