Curiosity rover finds carbon deposits on Mars - more evidence of water on surface / Signs of Liquid Water Under Martian Surface Boost Possibility of Life / Evidence of hot water that's essential to life points to Mars' habitable past / Rocks collected on Mars hold key to water and perhaps life on the planet: Researchers urge bringing them back to Earth / Scientists find evidence of liquid water deep underneath the Martian surface / New study suggests ocean of water lies beneath Mars's surface / Water frost on Mars: On the top of immense volcanoes, a briefly icy landscape