The dark material coating some of the geologic features of Jupiter's moon Europa could be sea salt, according to NASA laboratory experiments. The sea salt could be from a subsurface ocean, darkened from exposure to radiation. The potential for a subsurface ocean is an important consideration in determining if the icy moon could support life.
"We have many questions about Europa, the most important and most difficult to answer being is there life? Research like this is important because it focuses on questions we can definitively answer, like whether or not Europa is inhabitable," said Curt Niebur, an Outer Planets Program scientist at NASA Headquarters in Washington, according to a press release. "Once we have those answers, we can tackle the bigger question about life in the ocean beneath Europa's ice shell."
"We call it our 'Europa in a can,'" Hand said, according to the press release. "The lab setup mimics conditions on Europa's surface in terms of temperature, pressure and radiation exposure. The spectra of these materials can then be compared to those collected by spacecraft and telescopes."
"This work tells us the chemical signature of radiation-baked sodium chloride is a compelling match to spacecraft data for Europa's mystery material," Hand said, according to the press release.
Additionally, the longer the samples were exposed to radiation, the darker the resulting color. Hand thinks scientists could use this type of color variation to help determine the ages of geologic features and material ejected from any plumes that might exist on Europa.
