Considered the largest moon in the solar system, Ganymede is believed to contain a liquid ocean 100 miles beneath its ice-crusted surface, which could potentially have conditions suitable for aquatic alien life.
Researchers utilized both new and archival datasets from NASA‘s Hubble Space Telescope to make the discovery of water vapor in the moon’s thin atmosphere. However, the water likely derives from ice vaporizing off of the moon’s surface, not the subterranean ocean.
The discovery expands scientists’ knowledge of Ganymede’s atmospheric contents, which previously only consisted of oxygen.
“So far only the molecular oxygen had been observed,” Lorenz Roth of the KTH Royal Institute of Technology in Stockholm, Sweden, who led the team who discovered the water vapor, told NASA. “This is produced when charged particles erode the ice surface. The water vapor that we measured now originates from ice sublimation caused by the thermal escape of water vapor from warm icy regions.”
The findings fuel anticipation for the European Space Agency‘s upcoming mission, JUICE (Jupiter Icy Moons Explorer). Scheduled for launch in 2022 and arrival at Jupiter in 2029, JUICE will make detailed observations of Jupiter and three of its largest moons over the span of at least three years.
“Our results can provide the JUICE instrument teams with valuable information that may be used to refine their observation plans to optimize the use of the spacecraft,” added Roth.