New findings: Juno detects salts and organic compounds on Ganymede’s surface

Juno Opens up Salts and Organic Compounds on Ganymede’s Surface
Jupiter’s largest moon, Ganymede, has long been a source of fascination for planetary scientists and astrobiologists. It is believed to have a massive ocean beneath its icy surface, making it a potentially habitable location in the solar system. Over the years, various missions and telescopes have observed Ganymede and its surface features, hinting at the presence of mineral salts and organic compounds. However, the low spatial resolution of these observations made it difficult to confirm their existence definitively.
Fortunately, NASA’s Juno mission, during its flyby of Ganymede in June 2021, was equipped with the Jovian Infrared Auroral Mapper (JIRAM) spectrometer, which provided high-resolution spectroscopic observations of the moon’s surface. This breakthrough allowed scientists to directly detect and analyze spectral features of non-water-ice materials on Ganymede, including hydrated sodium chloride, ammonium chloride, sodium bicarbonate, and possibly even aliphatic aldehyde.
These findings provide valuable insights into Ganymede’s formation and the composition of its early surface. The presence of ammoniated salts suggests that Ganymede may have accumulated materials cold enough to condense ammonia during its formation. The carbonate salts could be remnants of carbon dioxide-rich ices. By studying these compounds and salts, scientists can gain a deeper understanding of Ganymede’s origins and the origins of Jupiter’s system of large icy moons, including Callisto and Europa.
Interestingly, the salts and organic compounds appear to be localized in areas protected by Ganymede’s magnetic field. Jupiter’s immense magnetic field creates energetic electron and heavy ion bombardment on its surrounding moons, which can negatively affect these compounds. The observations from Juno’s flyby showed that the greatest abundance of salts and organics was found in the dark and bright terrains at latitudes shielded by the magnetic field. This suggests that the salts and organics are remnants of a deep ocean brine that reached the surface of Ganymede.
Understanding the makeup of Ganymede and other icy moons is important for assessing their habitability. Each of these moons is believed to have large subsurface oceans, making them potentially habitable locations in the solar system. Juno’s ongoing mission around Jupiter will continue to provide detailed observations of these moons, allowing scientists to further investigate their characteristics and habitability. Additionally, upcoming missions such as ESA’s JUICE and NASA’s Europa Clipper will focus exclusively on studying the icy moons and their unique features.
In conclusion, Juno’s recent flyby of Ganymede has provided groundbreaking insights into the presence of mineral salts and organic compounds on the moon’s surface. These discoveries shed light on Ganymede’s formation and the composition of its early days. By studying these compounds, scientists can gain a better understanding of the origins of Ganymede and Jupiter’s system of large icy moons. This knowledge is important for assessing the potential habitability of these moons and their subsurface oceans.