Martian Gullies Not Made By Water After All?

THE Mars Global Surveyor, back in 2000, detected gullies that some scientists believed were created by liquid water flowing on the surface in the recent history of the planet (for ‘recent’, read ‘last million years’). Gwendolyn Bart, a graduate student in planetary sciences at the University of Arizona, thinks that they may in fact be due to landslides caused by wind and asteroid strikes, having found evidence that the thoroughly water-free Lunar landscape has similar features.