Recently, researchers reported the discovery of two new types of salt ice. These new substances, which can only form at high pressures and low temperatures, could be i principal components of the icy surfaces of moons such as Europa and Ganymede.
The crystals that form in the salt water ice on earth they are quite simple: just two water molecules per sodium chloride. But these new substances, said hydrate, have a structure never seen in nature and contain much more water than salt. One of them contains 13 water molecules per sodium chloridewhile the second contains as many as 17.
“It’s rare these days to have breakthroughs in science,says astrobiologist and study author Baptiste Journaux.Water and salt are very well known in terrestrial conditions, but beyond that we are in the dark. And now we have these planetary objects that may contain compounds that we know well but in completely exotic environments.“
The special composition of the newly discovered type of ice could finally explain the famous red streaks that we see on the surface of some icy moons, including Europa. “It has the structure planetary scientists have been waiting for,” added Dr. Journaux.
According to the researchers, the extreme conditions that they managed to replicate in the laboratory could be commonplace on Jupiter’s satellites. They believe that a 10km ice surface can hide oceans, as well as a denser form of ice on the seabed.
An exciting prospect, which can be confirmed when the mission JUICE of the European Space Agency it will reach the icy moons of Jupiter.
The researchers’ study illustrates how the pressure to be the main driver of diversity in the crystalline structure of ice. “Pressure brings molecules closer together, changing their interactions,” Dr. Journaux explains. After observing the formation of the new hydrates, one of the two remained stable even after the pressure was released.
Scientists now plan to continue their research on the salty ice, in hopes of obtaining results to compare them with the chemistry of Jupiter’s satellites. Staying on topic, only some time ago it was discovered a new form of ice (without salt this time) never seen before.