Heavily-cratered Callisto is only a little smaller than Ganymede and, like Europa, might be hiding a subterranean ocean.
Heavily-cratered Callisto is only a little smaller than Ganymede and, like Europa, might be hiding a subterranean ocean.
布满陨石坑的克利斯托星仅仅稍小于格尼梅德星，它可能与欧罗巴星相似,蕴藏着地下海洋。