Like Earth, Mars has an atmosphere, a hydrosphere, a cryosphere and a lithosphere. In other words, Mars has systems of air, water, ice, and geology that all interact to produce the Martian environment.

What is the evidence that Mars once had a hydrosphere?

The rover has found geological evidence that lakes of liquid water existed in the crater 3.5 billion years ago. "The lakes may have existed for hundreds of thousands of years," says John Grotzinger, a researcher at Caltech and chief scientist for the rover.

Was there ever water on Mars?

It is widely accepted that Mars had abundant water very early in its history, but all large areas of liquid water have since disappeared.