Mystery dark material on Jupiter's moon is sea salt: NASA

Washington: NASA scientists have revealed that the mysterious dark material on Jupiter's moon Europa is sea salt from a subsurface ocean, discoloured by exposure to radiation. The presence of sea salt on Europa's surface suggests the ocean is interacting with its rocky seafloor, an important consideration in determining whether the icy moon could support life.

For more than a decade, scientists have wondered about the nature of the dark material that coats long, linear fractures and other relatively young geological features on Europa's surface. Its association with young terrains suggests the material has erupted from within Europa.

"If it is just salt from the ocean below, that would be a simple and elegant solution for what the dark, mysterious material is," noted lead researcher Kevin Hand, planetary scientist at NASA's Jet Propulsion Laboratory in Pasadena, California.

One certainty is that Europa is bathed in radiation created by Jupiter's powerful magnetic field. Electrons and ions slam into the moon's surface with the intensity of a particle accelerator. Theories proposed to explain the nature of the dark material include this radiation as a likely part of the process that creates it.