Martian gullies that some scientists believe were recently carved by liquid water might instead be the result of landslides triggered by wind and meteor impacts, scientists say.
The idea is based on new findings that the Moon, where no liquid water has been found, contains gullies similar to those found on Mars.
Gwendolyn Bart, a graduate student in planetary sciences at the University of Arizona, presented her findings last week at the 37th Lunar and Planetary Science Conference in Houston.
Many scientists think Mars was a planet once drenched in water, at least for periods of time: its surface contains canyons larger than any found on Earth. NASA’s Mars rover Opportunity has found BB-like spheres and layered deposits of sandstone that many scientists believe could have only formed under conditions in which large bodies of water existed at or near the Martian surface for long periods of time.
But these findings only confirm the presence of Martian water in the ancient past. Whether liquid water ever exists on the planet now is a subject of debate among scientists.
In 2000, NASA scientists announced that the Mars Global Surveyor, or MGS, satellite had detected gullies apparently formed from water trickling up from just below the surface. Based on the images, some scientists concluded that liquid water flowed on Mars’ surface in the recent past, sometime within the last million years, and that liquid water might still exist on the planet in subsurface reservoirs.
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