Scientists may have found signs that salt water exists on Mars, which would be one of the biggest clues yet that life possibly exists on the planet. At a NASA news conference on Thursday, they announced the discovery of dozens of slopes across the planet's southern hemisphere. When Mars gets warm, the slopes appear in the form of dark streaks that expand downhill, then the streaks disappear during the cold season, when water presumably freezes up. They believe the streaks signify a salty, syrupy-like water running on or below the planet's surface, and have counted as many as 1,000 possible streams flowing down from the planet's Newton Crater and into a basin. "If we confirm that it is a salty water, then we have the best idea yet about where to go to try to find extant life on Mars,” said the lead author of the study.