Rover Finds Martian Rivers Flowed Longer Than Thought

(CN) – New research challenges perceptions of Mars' climate history with findings that broad, fierce rivers may have flowed across the Red Planet as recently as 1 billion years ago.

In studying images taken by the Mars rover, among others, researchers found the gullies and trenches carved by these rivers were twice as wide as rivers on Earth and showed evidence of high-volume water movement which was either constant or cyclical with the planet’s arid and wet seasons.

The research, published Wednesday in the journal Science Advances, challenges the generally understood timeline of water on Mars.

Previously, scientists believed most of the water on Mars had migrated to the polar ice caps by 3.6 billion years ago, with the planet going from a wet to dry surface as the atmosphere thinned. But the team that conducted Wednesday’s study point out topographic evidence shows high-volume rivers were flowing on Mars a billion years ago, driven by a precipitation cycle and not short-term runoff from asteroid impacts.

Using image data of well-preserved paleo-river channels, alluvial fans and deltas across Mars, and calculating the intensity of river runoff using multiple methods including an analysis of the size of the river channels, researchers estimate that 3 to 20 kilograms per square meter of water ran along these channels each day.

If the dates for these massive rivers are correct, the findings could suggest that Mars' late-stage atmosphere disappeared faster than previously calculated, or that there were other drivers of precipitation under low-atmosphere conditions.

The paper’s authors acknowledge the problem that their findings hold for climate modeling of Mars, and encourage re-thinking the conventional wisdom.

“Our results globalize and intensify the challenge set to climate modelers by Mars Science Laboratory rover results of explaining late-stage river-forming climates on Mars,” the researchers wrote.

Study authors include Edwin Kite and David Mayer of the University of Chicago, Sharon Wilson of the Smithsonian’s Center for Earth and Planetary Studies, Joel Davis of the Natural History Museum in London, Antoine Lucas of Institut de Physique du Globe de Paris, Centre National de la Recherche Scientifique in Paris, and Gaia Stucky de Quay of the University of Chicago and Imperial College London.

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