Scientists May Have Just Found 'Table Salt' in Subsurface Ocean of Jupiter's Icy Moon Europa

Table salt, or sodium chloride is a seemingly unremarkable substance which is ubiquitous in our everyday lives.

Now a team of scientists has identified the compound on Europa—Jupiter's fourth largest moon—and one of the most promising candidates in the search for signs of extraterrestrial life in our own solar system.

In light of their findings, the team from Caltech and NASA's Jet Propulsion Laboratory, suggest that Europa's subsurface ocean may be much more similar to Earth's than previously thought, according to a study published in the journal Science Advances.

The evidence for a subsurface ocean on Europa first began to emerge when scientists analyzed data collected by the Voyager and Galileo spacecrafts. Now, the consensus is that the moon is completely covered by a layer of salty liquid water perhaps ten times as deep as the Earth's ocean.

The subsurface body of water—which is encased in an icy shell—is thought to be billions of years old and may contain as much as three times the volume of all the liquid water on Earth.

Scientists suggested that due to the nature of the relatively young icy shell, any salts on the surface of Europa must have originated from the underground ocean.

The data collected by Galileo of Europa's surface indicated the presence of a salt known as magnesium sulfate, thus researchers initially thought that this is what the ocean below contained.

But now, using observations conducted by the Hubble Space Telescope, the authors of the latest study identified the chemical signature of table salt in an area of Europa's surface known as Tara Regio, which is yellowish in color.

"We've had the capacity to do this analysis with the Hubble Space Telescope for the past 20 years. It's just that nobody thought to look," Mike Brown, a co-author of the study and planetary scientists at Caltech, said in a statement.

The authors warn that their results do not provide concrete evidence that the sodium chloride they detected actually comes from the subsurface ocean.

Nevertheless, the finding has the potential to transform our understanding of the composition of Europa's ocean, opening up the possibility that it is chemically similar to the Earth's.

"Magnesium sulfate would simply have leached into the ocean from rocks on the ocean floor, but sodium chloride may indicate that the ocean floor is hydrothermally active," Samantha Trumbo, lead author of the paper from Caltech, said in a statement. "That would mean Europa is a more geologically interesting planetary body than previously believed."

Tara Regio is the yellowish area to the left of center in this Galileo image of Europa’s surface. This region is the area researchers identified an abundance of sodium chloride. NASA/JPL/University of Arizona