When will we explore Jupiter's moon Europa?

Does Jupiter's ice moon Europa glow in the dark?

The researchers developed an instrument with which they could bombard chunks of ice with a Jupiter-like stream of electrons from a safe distance and track what was happening. When they aimed the electron beam at a frozen block of pure water, it started to glow. When they switched to sodium chloride ice, the light almost disappeared. At first the researchers thought that something had gone wrong and tried again - but the strong glow did not appear.

“That was the aha moment for us,” says Gudipati.

He and his team tested various salts that studies have shown could be stored on the surface of Europe. Some salts, such as carbonates, dimmed the glow; others, such as magnesium salts, increased it. And there was another insight: depending on the composition of the ice, the color of the glow also changed. Sodium chloride, for example, resulted in green light, adding sulfate salts made the mixture of light reddish. The results suggest that the composition of various salts influences a possible glow on the surface of the ice moon - which could help "to see Europe from a completely different perspective," says Gudipati.

Search for extraterrestrial life

The calculations by Gudipati and his team give rise to hope that the glow of the moon could be strong enough to be captured by the camera of the Europa Clipper space probe. But that is far from certain, warns Niebur - also because the camera in question is still being built.