A Son of the Rock

This picture (from Astronomy Picture of the Day 14/5/12) shows all the water of Jupiter’s moon Europa as if gathered into a ball and a similar depiction is done for Earth.

If you look at the sizes of the two spheres of water you can see Earth actually has comparatively little. It’s just spread over a large area (the oceans.) Europa has more water in total. A good place to look for extraterrestrial life then, perhaps.