Besides the earth, which planet has liquid water?

Its surface is covered with a layer of ice. The density of Europa shows that it has a water ice layer as thick as 100 km, some of which may be liquid. At present, it is generally believed that this layer of structure extends from the surface of Europa to the rock layer inside it. But from the photos sent back, the movement of those broken ice blocks is caused by liquid water or ice below the surface when the ice layer breaks.

The photo of Europa taken by NASA's Galileo Jupiter probe on1June 27, 996 shows the floating ice on Europa, which is similar to the polar ocean of the earth. This layer of ice is divided by dark bands of various shapes, and some fragments can be as wide as 30 kilometers. The material filled between the fragments may be a mixture of mud and ice or rock fragments, and some independent fragments are separated and moved to other locations. In June 2000, when Galileo Jupiter probe flew over Europa at an altitude of about 350 kilometers, it was also observed that Europa's magnetic field reversed every five and a half hours. From this phenomenon, we can think that there is some kind of conductive liquid (such as salt water) flowing inside Europa. The high reflectivity of Europa shows that the surface of Europa is still covered under the ice. According to the fact that the photo of its surface is very similar to the photo of ice on the earth's ocean, scientists speculate that there may be an ocean composed of liquid water on Europa, which means that there is a layer of liquid water under the ice shell on Europa's surface. The estimated depth may reach 90 km (the deepest part of the earth's ocean is only 1 1 km), and the heat necessary to maintain the liquid ocean is likely to come from the heat brought by tidal force.

If so, Europa will be the only place in the solar system with a lot of liquid water besides the earth. Based on this, scientists believe that there is the possibility of some life form inside Europa.