Planetary bodies differ from one another in their composition, but most of those in the Solar System have solid surfaces  Unless the core of such a planetary body generates enough heat to cause volcanic action, the surface of the body will not be renewed for millions of years  Any planetary body with a solid surface whose surface is not renewed for millions of years becomes heavily pockmarked by meteorite craters, just like the Earth' s Moon
Some old planetary bodies in the Solar System, such as Europa, a very cold moon belonging to Jupiter, have solid icy surfaces with very few meteorite craters
Some planetary bodies whose cores generate enough heat to cause volcanic action do not have solid icy surfaces.