New images taken from NASA’s Mars Reconnaissance Orbiter show that huge lakes of melted ice may have once existed on ancient Mars. The lakes suggest a possible warm, wet period that may have occurred more recently than previously thought. Scientists hope to prove that these ancient lakes may have hosted life of some form.

Thus far, there is no firm evidence of any past or present Martian biology. But these new photos show winding channels that link several lake-like depressions in the Martian surface. NASA speculates that these channels could only have been caused by Martian lake water running between the depressions about 3 billion years ago. We already know that water once existed on Mars, based on the data collected from other satellites and the Mars rovers. Previous studies also suggest that Mars was warm and wet enough to support liquid lakes around 4 billion years ago. 

But this new evidence suggests that Mars could have sustained lakes even later. Nicholas Warner is a researcher who led the study at the Imperial College of London. As Warner explains, "Excitingly, our study now shows that this middle period in Mars' history was much more dynamic than we previously thought."

The research, detailed in the Jan. 4 issue of the science journal Geology, shows that the channels run between huge depressions in the Martian surface located near a 1,242-mile (2,000 km) gorge called Ares Vallis across the planet's equator. Previously, experts thought that the depressions were formed by a process called sublimation, when ice transitions directly into gas. Not so, now claim researchers. Scientists point out that similar channels can be seen on Earth in Alaska and Siberia, where permafrost melts to carve drainage channels that connect different lakes.

The details of the ancients lakes are still unknown. But scientists feel that the lakebeds could provide excellent targets for future probes to Mars. Microbial life may have been plentiful on a warm, wet Mars, and its evidence might be seen in these depressions. Scientists plan to use the Reconnaissance Orbiter to look for evidence of other primordial lake beds.