Mars Was Wet More Recently Than Previously Thought
September 15th, 2016, 6:00AMUsing data collected by NASA’s Mars Reconnaissance Orbiter, scientists have discovered that flowing water existed on Mars much more recently than previously thought. Scientists had already found evidence that Mars had a wet period about three to four billion years ago before most of the atmosphere was lost and the remaining water froze. New evidence from MRO’s HiRISE camera, however, shows craters and valleys that were likely lakes and streams that appeared a few hundred million years after that period. Teams at the University of Virginia, NASA, and the Smithsonian are now focused on how the climate on Mars would have warmed up enough during the interim period to liquify the planet’s water, suggesting one possibility is an extreme change in the planet’s tilt.