Water on Mars was once widespread and long-lasting, providing environments with the potential to support life, a new study finds.
Previously, scientists had strong evidence that liquid water chemically altered the Red Planet’s crust at certain times and locations. Those locations hold the mineral traces of water and preserve in the rock the planet’s past organic chemistry, says Scott Murchie, co-author of the new paper published in the July 17 Nature.
Those locations are also “really important” because the rocks there could hold possible evidence of past life, says Murchie, of the Johns Hopkins University Applied Physics Laboratory in Laurel, Md.
Using the Compact Reconnaissance Imaging Spectrometer for Mars, or CRISM, and other instruments aboard NASA’s Mars Reconnaissance Orbiter, the team looked for specific types of phyllosilicates, or clay-like minerals, that can form only in the presence of water. The team suggests the water was present early in the solar system’s history, between 4.6 billion and 3.8 billion years ago, based on where in the planet’s rocky layers the minerals occur.
Scientists previously identified a few types of these minerals at about 100 sites, but the sensitivity of CRISM picked up a large variety of the phyllosilicates at thousands of locations across Mars’ southern highlands.
“Finding all these different water-based minerals at all these locations really blows the doors off Mars research,” says University of Paris’ Joseph Michalski, a Mars researcher who was not involved in the study. But, he adds, it all will take years of scientific study and debate to understand what these sites mean for the history of Mars, and whether these sites hosted life.