A recent study done with the Hawaii Keck telescope looked at spectra from Jupiter’s famous icy moon Europa. Many scientists have speculated that the moon may harbor life in an ocean underneath its thick ice shell. Now, spectra are showing a magnesium sulfate compound on the surface of the ice. While it is though the sulfate component may have come from the volcanic moon Io, it is still speculated that the magnesium may be from salts within the ocean. Thus, there is hope there are similar salts in Europa’s ocean to what is in Earth’s ocean. Read more about this here.