New Map Suggests Mars Once Humid

November 24, 2009 1:51 p.m. EST

West Palm Beach, FL (AHN) - A new detailed computer-generated map of Mars released Monday shows what scientists believe was a vast ocean in the planet's north region, and valleys around the equator, suggesting a once-humid, rainy climate.

The map, constructed based on topographic data collected by NASA satellites, also shows the extensive network of valleys and just how much more complex they were than originally estimated. Northern Illinois University geography professor Wei Luo said the valleys on Mars were created by the same process as most of the valleys on Earth, precipitation-fed runoff erosion.

Debate has been brewing over how the ancient Martian valley networks were created ever since NASA's Mariner 9 space probed discovered them in 1971. Some argued that the valleys formed from water erosion, suggesting humidity and rainfall. Others said they formed through ground water sapping erosion, meaning cold and dry conditions.

The full report can be found in the Journal of Geophysical Research.