NASA's Juno spacecraft has made a significant discovery on Ganymede, Jupiter's largest moon, indicating the presence of salts and organic compounds on its surface. This finding adds to the growing evidence that Ganymede possesses a subsurface ocean beneath its icy crust.
The revelation came during a close flyby of Ganymede in June 2021 when Juno utilized its Jovian InfraRed Auroral Mapper (JIRAM) spectrometer to analyze the moon's surface chemistry and interactions. Ganymede, with its vast ocean hidden beneath its icy exterior, has been a target of scientific interest for years.
The JIRAM instrument achieved an unprecedented level of spatial resolution, providing clear data on the composition of Ganymede's surface. Among the discoveries were hydrated sodium chloride, ammonium chloride, sodium bicarbonate, and possibly aliphatic aldehydes, which are organic compounds.
What makes this discovery particularly intriguing is that Ganymede's neighbor, Jupiter, boasts an immensely strong magnetic field that should, in theory, make it challenging for organic compounds and salts to exist on its moon's surface. However, the region around Ganymede's equator appears to be adequately shielded from Jupiter's harsh magnetic field, allowing these compounds to persist.
Scientists speculate that these findings could suggest the existence of hydrothermal activity deep beneath Ganymede's icy surface or interactions between its subsurface ocean and the planet's interior rocks.