Jupiter’s icy moon Europa might give the phrase “Moonlight” a whole new meaning. A series of new experiments by NASA scientists suggest that the icy moon shines, even on its night side.
As Europa, the icy moon (consisting mainly of water ice and various salts) and filled with oceans, orbits the gaseous planet Jupiter, resisting a relentless blast of radiation. Jupiter hits the surface of Europa day and night with electrons and other particles, bathing it in high-energy radiation. And, as these particles hit the surface of the moon, They make Europe glow in the dark.
On Earth, when the Moon shines in our sky, what allows us to see it is because it reflects sunlight. This is so for most bodies in the solar system, but Jupiter’s moons are out of the ordinary by existing in a fiercely radioactive environment where they are constantly bombarded care a wide variety of subatomic particles of the gas giant.
To better understand the effects of this huge radiation on a moon like Europa, scientists created a laboratory mockup from the surface of Europa at a high-energy electron beam facility in Gaithersburg, Maryland, and used an instrument called the Ice Chamber for the Europa High-Energy Electron and Radiation Environment Testing (ICE-HEART).
So when the researchers simulated that interaction in the lab by firing electrons at samples of salty ice, the ice shone. The brightness of that glow depended on the type of salt in the ice, according to the researchers in their study published in the journal Nature Astronomy.