Jupiter’s moon Europa has long been known as an ocean world, where evidence has continued to indicate that there is a global ocean of liquid water deep below the surface shell of ice. The environment is thought to be similar to ice-covered seas and oceans at the poles on Earth. But now there is also new evidence for lakes on Europa, which are inside the ice crust itself, between the surface and the ocean below. The lakes are thought to be about equal in volume to the Great Lakes in North America.
The data actually comes from a previous mission to Jupiter, Galileo, which provided scientists with decades worth of information to analyze about Jupiter and its moons.
With a deep ocean, Europa has become a prime candidate in the search for life elsewhere in the solar system. The question of habitability though, depends to some degree on how thick the ice shell is. If too thick, it would be difficult for organic nutrients and energy to be transferred between the surface and the ocean below. If thinner though, then it would be much easier, making life more plausible. The answer now seems to be a sort of compromise; the ice shell is thick in most places, but in some areas, known as “chaos terrain,” it is thinner, where it overlies the lakes.
According to Britney Schmidt, lead author of the paper and postdoctoral fellow at the Institute for Geophysics, University of Texas at Austin, “One opinion in the scientific community has been if the ice shell is thick, that’s bad for biology. That might mean the surface isn’t communicating with the underlying ocean. Now, we see evidence that it’s a thick ice shell that can mix vigorously and new evidence for giant shallow lakes. That could make Europa and its ocean more habitable.”