The lunar surface of Europa can glow in the dark thanks to Jupiter’s radiation

The moon Europa, one of 79 orbiting Jupiter, is a frozen world that hosts an ocean beneath its surface, which may even contain some kind of life. As it orbits the largest gas giant in the Solar System, this moon receives electrons and other particles that bathe it with highly energized radiation, which can glow in the dark. Therefore, new research by scientists at NASA’s Jet Propulsion Laboratory (JPL) has detailed what the glow would look like and what it can reveal about the moon’s composition.

In other observations, scientists had previously assumed that Europa’s surface would consist of a mixture of ice and common salts, such as sodium chloride – table salt – and magnesium sulfate, Epsom salt, which can be used. in the bathrooms. Thus, the study, with scientists led by physicist Murthy Gudipati, suggests that radiation from Jupiter’s magnetic field could cause Europa’s surface to glow due to chemical reactions with ice. “These charged high-energy particles, including electrons, interact with the salt and ice-rich surface, which results in physical and chemical processes,” explain the authors.

For the study it was necessary to imitate the conditions of the moon. Therefore, during the experiments, the team cooled the ice to about -173.15 ° C, so the ice was exposed to pulses of electronic radiation. Scientists noticed that the ice emitted a glow, the intensity of which depended on the substances present in the water. “Europa’s ice analogs emit the characteristic spectral signatures in the visible region when exposed to high-energy electron radiation,” state the authors.

In this, they found that sodium chloride and carbonate are compounds capable of reducing ice glare, while epsomite increases it. For Fred Bateman, co-author of the study, “seeing sodium chloride shimmer less was ‘aha!’ which changed the course of research “- this is because, initially, the goal was to verify how organic material under the moon’s ocean interacts with radiation emissions, and the researchers were surprised when they realized that the brightness varied depending on the composition of the ice.

At first glance, a moon shining in the dark may not seem like that much; after all, our moon shines by reflecting the sunlight. However, Europa’s brightness is caused by a very different mechanism, which is capable of illuminating it even on the side that does not receive sunlight. “If Europe did not have this radiation, it would look like our Moon – dark on the side that is in shadow,” explains Gudipati, lead author of the study.

Europa’s surface will be better observed by the Europa Clipper mission, which is expected to launch in the mid-2020s, and the mission scientists are analyzing the authors’ results to find out if the brightness could be detected by the spacecraft’s scientific instruments. If Europa Clipper’s systems can observe brightness and analyze the spectrum, we can get new information about that moon’s ice composition. Additionally, the techniques can also aid in the analysis of other Jovian moons.

The results of the study were published in the journal Nature Astronomy.

Source: ScienceAlert, NASA