As an icy, ocean-filled satellite, Europa orbits Jupiter, and it keeps receiving vast waves of radiation.

These observations may also allow scientists to figure out the chemical make-up of the moon's sub-surface ocean - for example, its salinity - something that Murthy Gudipati, lead of author of the study and a principal scientist at NASA's Jet Propulsion Laboratory at the California Institute of Technology, said would be "important for potential habitability". As we don't completely understand the chemical composition of Europa's icy surface, what exactly these processes look like remains to be a mystery. "How that composition varies could give us clues about whether Europa harbors conditions suitable for life". It is also part of a group of four moons known as "Galilean Moons" Through earlier observations, scientists have concluded that the moon's surface could be composed of a mixture of ice and other commonly found salts on Earth, such as sodium chloride (table salt) and magnesium sulfate (Epsom salt).

NASA's Europa Clipper mission is slated for launch in the mid-2020s and aims to conduct a detailed survey of Europa, from the thin atmosphere to the subsurface ocean to the deep interior. It's possible that information gathered by the spacecraft could be matched with the measurements in the new research to identify the salty components on the moon's surface or narrow down what they might be.

JPL scientists used a spectrometer to compare the wavelengths of the emitted light from the moon to gain insights into the specific compounds within the ice responsible for each particular hue.

Visible glowing from the irradiated ice core in lit, dimmed, and dark conditions. When the energy-laded electrons penetrate through the surface, the molecules underneath are energized. When those molecules relax, they release energy as visible light. The study was based on a laboratory mock-up using an instrument called the Ice Chamber for Europa's High-Energy Electron and Radiation Environment Testing or ICE-HEART.

"There have historically been debates about the identities of some of these salts on the surface of Europa", said Bryana Henderson, JPL scientist and co-author on the study.

In news that is sure to delight every kid with stickers of stars and planets on their ceiling, planetary scientists have discovered that the night-side of Jupiter's moon Europa may glow in the dark. And the glow changed depending on the chemical makeup of the ice block. "But we never imagined that we would see what we ended up seeing". "When we tried new ice compositions, the glow looked different". And we all just stared at it for a while and then said, 'This is new, right?

On Europa, which is around the same size as Earth's moon, temperatures range from as high as about 140 Kelvin (about -210 degrees Fahrenheit) at the moon's equator to as low as about 50 Kelvin (-370 degrees Fahrenheit) in icy patches at the moon's poles.

This artist's illustration shows what Europa's nightside glow might look like. The study, thus, offers the peculiar possibility of a moon that continuously glows even on the side that faces away from the sun-its dark side or nightside.

"If Europa weren't under this radiation, it would look the way our moon looks to us - dark on the shadowed side".

The Clipper team is looking at the results of the new study, which was published online Monday (Nov. 9) in the journal Nature Astronomy, to determine if Europa's glow could be detectable by the spacecraft's instruments, NASA officials said in the same statement.

While visiting Europe in person may not be a novice, NASA already has a spacecraft in the works, the Europa Clipper mission, scheduled to start in 2024 and examine the moon as it orbits Jupiter.