How Mars could have been warm and wet enough to form ancient valleys

Washington – Researchers have said that much like the Grand Canyon, Nanedi Valles snakes across the Martian surface suggesting that liquid water once crossed the landscape.

The researchers said that the presence of molecular hydrogen, in addition to carbon dioxide and water, could have created a greenhouse effect on Mars 3.8 billion years ago that pushed temperatures high enough to allow for liquid water.

The team includes Ramses M. Ramirez, a doctoral student working with James Kasting, Evan Pugh Professor of Geosciences, Penn State used a model to show that an atmosphere with sufficient carbon dioxide, water and hydrogen could have made the surface temperatures of Mars warm to above freezing.

Those above-freezing temperatures would allow liquid water to flow across the Martian surface over 3.8 billion years ago and form the ancient valley networks, such as Nanedi Valles, much the way sections of the Grand Canyon snake across the western United States today.

Ramirez said that the findings are exciting because explaining how early Mars could have been warm and wet enough to form the ancient valleys had scientists scratching their heads for the past 30 years.

Ramirez and post-doctoral researcher Ravi Kopparapu co-developed a one-dimensional climate model to demonstrate the possibility that the gas levels from volcanic activity could have created enough hydrogen and carbon dioxide to form a greenhouse and raise temperatures sufficiently to allow for liquid water.

Once they developed the model, Ramirez ran the model using new hydrogen absorption data and used it to recreate the conditions on early Mars, a time when the sun was about 30 percent less bright than it is today.

The study has been published in the journal Nature Geoscience.