New Mars theory may hold water The Globe and Mail

A geologist says he may have figured out what caused mysterious gullies on Mars: water trickling from the melting of snow that had built up over thousands of years. His theory may help scientists figure out where to seek signs of life on the planet. The research suggests that even though Mars is now very cold, flowing water may have carved the gullies in the middle latitudes within the past 500,000 years.