Mars is too cold for liquid water these days, but scientists are constantly debating if oceans covered the Red Planet billions of years ago. A new study from France suggests that Mars was once a "watery world."
James Wray, an assistant professor in the School of Earth and Atmospheric Sciences, studies Mars as part of Georgia Tech's Planetary Surface Geology Group. He and his peers are searching for life in the universe or conditions that could support life.
"The evidence for rivers, lakes, and groundwater on ancient Mars is now indisputable, but whether there were even larger water bodies (seas or oceans) has been debated for decades now. This study shifts the debate back toward "yes," but does not resolve the issue. The paper provides a very important new constraint: the radar signature of Mars's northern hemisphere is consistent with a widespread sedimentary (not volcanic) deposit, which is either porous or saturated with ice. The authors favor a porous sedimentary deposit, but recent orbital images have shown ice to be more widespread across the northern hemisphere than expected (http://hirise.lpl.arizona.edu/HiBlog/tag/water/).
Also, there are ways to deposit porous sediments that don't require an ocean. The inferred sedimentary deposit's apparent restriction to some of the lowest terrains on Mars is tantalizing, but there are multiple processes (including winds) that could have deposited sediments at low elevations. Hopefully this work will motivate further studies of Mars's northern plains. Some day we would love to drill there!"
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