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Mars gullies likely not formed by liquid water

30 July 2016 Astronomy Now

New findings using data from NASA’s Mars Reconnaissance Orbiter show that gullies on modern Mars are likely not being formed by flowing liquid water. This new evidence will allow researchers to further narrow theories about how Martian gullies form, and reveal more details about Mars’ recent geologic processes.

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Gullies on Mars sculpted by dry ice rather than liquid water?

23 December 2015 Astronomy Now

Mars’ gullies may be formed by dry ice processes rather than flowing liquid water, as previously thought. This is the conclusion of a study conducted by two French scientists published in Nature Geoscience. They show that, during Martian late winter and spring, underneath the seasonal CO2 ice layer heated by the Sun, intense gas fluxes can induce gas-lubricated debris flows which look like water-sculpted gullies on Earth.

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Gully patterns document Martian climate cycles

29 January 2015 Astronomy Now

A new analysis of gullies carved into Martian impact craters suggests the Red Planet has undergone several ice ages in the last several million years. The driver of these climate swings is likely the planet’s wobbly axis tilt.