The extensive valley networks on the surface of Mars were probably created by running water billions of years ago, but the source of that water is unknown. Now, a team of Penn State and NASA researchers is using climate models to predict how greenhouse warming could be the source of the water.
"Everyone is looking for life on Mars, and if Mars was habitable early on as indicated by flowing water, then the chances of there being some sort of life there now goes up," said Natasha Batalha, graduate student in astronomy and astrophysics, Penn State. "Our work involves using models to best estimate what was happening on the surface of Mars 3.8 billion years ago."
Previous studies analyzing craters support the idea of flowing water on early Mars but still unknown is how surface warming occurred to melt that water and how much water was really there.
"If we compare some of these valleys on Mars to what we know on Earth, for example the Colorado River, then they look to be the same width," said James Kasting, Evan Pugh Professor of Geosciences, Penn State. "We know how much water it took to carve the Grand Canyon based on five to six million years of rainfall, which is estimated to be about three to six million feet (of rainfall)."
In 2014, Kasting's group proposed a climate model showing Mars warmed by a dense atmosphere of greenhouse gases, specifically carbon dioxide and hydrogen. In a recent issue of Icarus, they report that using a photochemical model, they determined the possibility that there was a high percentage of hydrogen in the atmosphere. According to Batalha and Kasting, photochemical models simulate different aspects of the atmosphere using mathematics to determine the chemicals and how they react. They also set limits that define what is happening at the surface and in the atmosphere.