The Scariest Ghost Worlds In Our Solar System

Mars The most thoroughly studied dead world in the solar system is also the clearest surviving record of a planet that once held water and lost it. It is the fourth planet from the Sun, roughly half the diameter of Earth, named by the Romans after their god of war for the color of its surface. That color comes from iron oxide, rust, coating a landscape of frozen desert and ice-capped poles. The conditions today are among the most hostile reachable by spacecraft. Average temperatures sit near minus 60 degrees Celsius, the atmosphere is less than one percent the density of Earth's, and liquid water cannot survive on the surface for more than moments before it freezes or boils away.