1st proof of water vapour on Jupiter's moon Ganymede found: NASA

Astronomers have uncovered evidence of water vapour in the atmosphere of Jupiter's moon Ganymede for the first time, NASA said. Researchers looked through the last two decades of data from the Hubble Space Telescope. Previous studies have shown that Ganymede may have more water than Earth, but as it is extremely cold, the water on the surface may be frozen.