An ocean may be hiding under the ice of Saturn's moon.

The diameter of Mimas is only 396 kilometers. It is covered with water ice and craters. Computer modeling has shown that the ice shell is too thin for the formation of the Herschel crater in its current form - only 30 kilometers. In addition, it turned out that Mimas can heat up enough to keep the ocean under the ice in a liquid state. Based on this, they suggested that the ocean of Mimas has been warming and expanding since the formation of the crater, and its ice shell has become thinner at that time.