Underwater snow on Earth could offer insight into Europa’s icy crust
In a new study, researchers studied two types of underwater snow found on Earth as an analog for understanding how Europa’s shell thickens from below. Frazil ice forms in supercooled water columns and floats upward to accrete onto the bottom of ice shelves, while congelation ice grows directly from under the ice shelf. Intriguingly, the researchers determined that ice formed by these processes retains just a fraction of the salt from the water from which it formed. Frazil ice retains just 0.1% of the ocean’s salinity and could be common on Europa, according to the study, suggesting that Europa’s ice shell could be orders of magnitude purer than previous estimates.