Water vapour found in Ganymede’s atmosphere

 New Delhi: For the first time, astronomers have uncovered evidence of water vapor in the atmosphere of Ganymede, one of Jupiter’s moon.

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The water vapour likely forms when ice from the moon’s surface sublimates, that is, it turns from solid to gas. The findings were made using new and archived datasets from NASA’s Hubble Space Telescope.

Previous research had offered circumstantial evidence that Ganymede, the largest moon in the solar system, contains more water than all of the Earth’s oceans put together. However, temperatures there are so cold that the water on the surface is frozen solid.

Also, Ganymede’s ocean is thought to be 100 miles below the moon’s crust. This means that the water vapor discovered by Hubble is not likely to represent the evaporation of this ocean.

Ganymede’s surface temperature varies strongly throughout the day. Around noon, near the equator, it may become warm enough for the ice surface to release small amounts of water molecules.

The European Space Agency’s upcoming mission JUpiter ICy moons Explorer (JUICE) – planned for launch in 2022 – will be able to confirm these findings. It will reach Jupiter in 2029, where it will spend at least three years, making detailed observations of Jupiter and three of its largest moons. The planet has at least 79 moons. Read more here.