NASA says that its Mars Curiosity rover has collected definitive proof that the planet could have once supported life.NASA scientists analyzed powder that Curiosity drilled out of a rock last month. They say the rock contains clay minerals needed for a watery environment. They also found traces of elements necessary to support life, including hydrogen, oxygen, and nitrogen.
Scientist John Grotzinger says the water that may have once been on Mars was harmless enough to drink.
Curiosity is not equipped to look for any microbes that may live on Mars today or fossils of those that are extinct.
Scientists believe Mars was once a warmer and moist environment before turning into a freezing dry desert.