An artist’s impression of what ancient Mars oceans may have looked like, based on gelogical data. Beafore and after comprassion of Mars surface ancient and today.
Mars may have had a denser atmosphere and higher surface temperatures, allowing vast amounts of liquid water on its surface, possibly including a large ocean that may have covered one-third of the planet. Although the Martian surface is now cold and dry, there is plenty of evidence suggesting that rivers, lakes and seas covered the Red Planet billions of years ago.