The yellow part of the watery moon of Jupiter? It's table salt, according to NASA

In the future, perhaps the rarest dish will be the salt of another world this is a possibility now that Caltech's planetary scientists and the Jet Propulsion Laboratory (JPL) of the NASA in Pasadena, California, announced their latest discovery: The common table salt on the surface of Europa, one of Jupiter's moons, exists.

"The discovery suggests that Europe's salt-water ocean could chemically resemble Earth's oceans more than previously thought, challenging decades of assumptions about the composition of these waters, "NASA said in a press release.

Well known as sodium chloride, the compound is a crucial part of the sea salt commonly found in the ocean. Sea salt also contains elements such as calcium, potassium and magnesium, but these generally consist of about 0.1% of the salt or less.

The scientists made the decision after studying the research acquired by NASA's Voyager and Galileo spacecraft. While browsing through the data obtained from the moon flyovers, originally discovered by the Italian astronomer Galileo Galilei in 1610, they discovered a visible yellow color on some parts of the moon's surface.

The Galileo spacecraft, launched in 1989 and entered the orbit of Jupiter in 1995, was equipped with an infrared spectrometer. The probe discovered that the entire moon appeared to be a giant ocean covered with an ice shell. From a geological point of view, the ice shell is still considered young. NASA thinks this means that everything in the hull is probably representative of what is underneath.

"People traditionally assumed that all the interesting spectroscopy is in the infrared on planetary surfaces, because it is there that most molecules researched by scientists have their basic characteristics," said Mike Brown, Richard and Barbara Rosenberg, professor of planetary astronomy. to Caltech and co-author of the Science Advances document describing the discovery.

Using the spectrometer to break down the wavelengths of Europa's striking light, the probe discovered ice-water and a substance that appeared to be magnesium sulfate salts, similar to the salts in the water. Epsom used for healing purposes on Earth. But that turned out to be a mistake. Data collected later from the high-end W.M. Keck observatory on the dormant Maunakea volcano in Hawaii showed that key fingerprints contained in magnesium had not been left on Europa.

NASA scientists have started experiments to determine the yellow substance. JPL scientist Kevin Hand sent the ocean salts across the ring with conditions similar to those in Europe, radiating them to the point of radically transforming them. Their colors have changed, on the one hand. Sodium chloride, in particular, has turned yellow.

"Sodium chloride is a bit like invisible ink on the Europa surface." Before the irradiation, one can not know it, but after irradiation, the color you is obvious, "explains Hand.

NASA then confirmed Hand's discovery directly at the source with the Hubble Space Telescope. In a region of the surface called Tara Regio, NASA was able to confirm the same yellow that corresponds precisely to the salt irradiated in Hand's laboratory.

"We've had the ability to do this analysis with the Hubble Space Telescope for 20 years," said Brown. "It's just that no one has thought of looking."

Like many discoveries on Europa, including the possibility of underwater geysers, this discovery only raises more and more questions about the moon.

"Magnesium sulphate would have simply infiltrated into the ocean rocks from the bottom of the ocean, but sodium chloride could indicate that the ocean floor is hydrothermally active," said Samantha. Trumbo, graduate student of Caltech, lead author of the article. "This would mean that Europa is a planetary body more geologically interesting than previously thought."

Source: JPL