Title: NASA’s Juno Mission Detects Salts and Organics on Jupiter’s Moon Ganymede
Subtitle: New findings shed light on the moon’s briny past and composition
Date: October 30, 2023
NASA’s Juno mission has made a groundbreaking discovery on Jupiter’s largest moon, Ganymede. Data collected by the Jovian InfraRed Auroral Mapper (JIRAM) spectrometer aboard the spacecraft reveals the presence of mineral salts and organic compounds on the moon’s surface. These findings, published in the journal Nature Astronomy, provide crucial insights into Ganymede’s origin and composition.
Ganymede, larger than the planet Mercury, has always fascinated scientists due to its massive hidden ocean of water beneath its icy crust. Previous observations by NASA’s Galileo spacecraft and the Hubble Space Telescope, along with the European Southern Observatory’s Very Large Telescope, hinted at the existence of salts and organics. However, the low spatial resolution of those observations limited any definitive conclusions.
On June 7, 2021, NASA’s Juno spacecraft made a close flyby of Ganymede, flying closer to the moon than any other spacecraft in over two decades. The flyby provided an opportunity for the JIRAM instrument to capture infrared images and spectra of the moon’s surface, revealing the chemical fingerprints of various materials.
The JIRAM data achieved an unprecedented spatial resolution for infrared spectroscopy, allowing scientists to detect and analyze non-water-ice materials with high accuracy. The presence of hydrated sodium chloride, ammonium chloride, sodium bicarbonate, and possibly aliphatic aldehydes was detected, offering vital clues about Ganymede’s formation.
According to Federico Tosi, a Juno co-investigator from Italy’s National Institute for Astrophysics in Rome, the presence of ammoniated salts suggests that Ganymede may have accumulated materials cold enough to condense ammonia during its formation. The carbonate salts found could be remnants of carbon dioxide-rich ices.
It is noteworthy that the JIRAM instrument’s coverage of Ganymede during the flyby focused on latitudes protected by the moon’s magnetic field, shielding them from the adverse effects of Jupiter’s intense radiation. These protected areas exhibited the greatest abundance of salts and organics, suggesting the presence of a deep ocean brine that reached the moon’s surface.
Ganymede is not the sole target of Juno’s exploration. The mission has also observed Jupiter’s moon Europa, another celestial body believed to harbor an ocean beneath its icy exterior. In the coming months, Juno will conduct a close flyby of Io, another of Jupiter’s moons known for its volcanic activity.
With these new findings, scientists hope to gain a deeper understanding of Ganymede’s origins, its internal processes, and the possibility of habitability. NASA’s Juno mission continues to unravel the mysteries of our solar system’s largest planet and its fascinating moons.
Reference:
“Salts and organics on Ganymede’s surface observed by the JIRAM spectrometer onboard Juno” by Federico Tosi, et al., Nature Astronomy, October 30, 2023.
NASA’s Jet Propulsion Laboratory (JPL), managed by Caltech in Pasadena, California, oversees the Juno mission. The project is part of NASA’s New Frontiers Program, managed at Marshall Space Flight Center in Alabama. The Jovian InfraRed Auroral Mapper was funded by the Italian Space Agency, and the spacecraft was built and operated by Lockheed Martin Space in Denver.