The new findings are an independent line of evidence that hydrothermal activity is taking place in the subsurface ocean of Enceladus. Earlier results, published in March 2015, indicated hot water is interacting with rock beneath the sea of this distant moon. The new discoveries support that conclusion and add that the rock appears to be reacting chemically to produce the hydrogen.
Ganymede: Ganymede is both the largest moon of Jupiter, our Solar System's planetary behemoth, as well as the largest moon in our entire Solar system. Observations of Ganymede by the HST in 2015 suggested the existence of a subsurface saline ocean. This is because patterns in auroral belts and rocking of the magnetic field hinted at the presence of an ocean. It is estimated to be approximately 100 kilometers deep with a surface situated below a crust of 150 kilometers.
So, the next time you're planning a big fishing trip, make sure you know when the moon sets and rises for that day and plan around it. You will find your fishing experience a much more rewarding one for having that bit of knowledge. I promise!