Jupiter’s second moon, Europa, is believed to have an ocean beneath its surface made of water and ice, and it is hoped that extraterrestrial life may exist. A team of researchers who have investigated how the Europa Ice Sheet is formed is arguing that the Europa Ice Sheet may be formed by snow falling upwards.
The Europa Clipper, a probe used by NASA to investigate Europa, was announced to be completed in June 2022 and is scheduled to be launched in 2024. A team of researchers at the University of Texas at Austin, who is leading the development of a radar device for the Europa Clipper, turned to the mystery of how the Europa ice sheet was formed as they studied how to penetrate the ice sheet and probe the ocean beneath it.
Europa is a quarter of the size of the Earth, and the surface ice sheet is 15 to 25 km thick, and the sea below is believed to be 60 to 150 km deep. Studies so far suggest that the Europa sea is relatively close to Lake Vostok, an ice-bottom lake in Antarctica, in temperature, pressure, salinity and concentration.
The team inferred how the Europa ice sheet formed from the main way the Antarctic ice sheet formed. One of the main methods of forming the Antarctic ice sheet is condensation ice, a type of ice that grows on the surface of an existing ice sheet. Another major method is Frazil ice. It is a fine needle-like, plate-shaped ice formed by the surface layer of the sea level that has fallen to the freezing temperature. Since the ice density is smaller than that of the surrounding seawater, the formed ice crystals float upward in the sea and settle at the bottom of the ice sheet.
As a result of investigating these two methods, it is said that ice formation is common in places such as Europa, where the temperature gradient is low and there is little temperature change with depth. In other words, most of the Europa ice sheet was most likely formed by underwater snow rising upwards from the sea.
The salinity contained in condensed ice is regarding 10% of the surrounding seawater, but the concentration of salinity in the frozen ice is only 0.1%. Therefore, this study’s findings that the Europa ice sheet is usually composed of fixed ice suggests that the ice sheet salinity may be orders of magnitude lower than previous estimates. As ice sheet salinity affects ice sheet strength and structure, as well as observations made by radar devices, such information is important for future Europa exploration.
When the team explores Europa, they say they are interested in sea salinity and composition, as this is one of the factors that determine habitability or the types of life that can inhabit it. Related content this placecan be checked in